Japanese maple winter damage


Frequently Asked Questions

Do all Japanese maples need to grow in the shade?

How often should I water my Japanese maple?

Should I fertilize my new Japanese maple to get it off to a good start?

When is the best time to plant Japanese maples?

Do all Japanese maples lose their leaves?

What is a dwarf Japanese maple?

What is the most common cause of failure in growing Japanese maples?

Do all Japanese maples need to grow in the shade?

No! Many Acer palmatum cultivars are very happy in a sunny exposure. This includes the red dissectums (or lace leaf maples), as well as trees with wider, palmate lobes. In fact, the red leaved trees need a few hours of sunlight to maintain their red color. In the Sculpture Gardens at Wildwood, one sees many maples growing in full sun. Summer temperatures exceed 100 degrees.

We have found that Japanese maples with green lace leaves prefer partial shade during the afternoon. Cultivars of Acer shirasawanum and Acer japonicum also appreciate filtered sun.

Note: A young tree planted out in full sun will struggle and may not survive. If you wish to start the tree out in full sun, we recommend selecting a specimen that is at least 6 or 7 years old.

How often should I water my Japanese maple?

Roots of these trees need to remain evenly moist; and roots are not deep. Establish a regular watering routine. The frequency of watering depends on the temperature and how well your soil holds moisture. Of course mulching is very helpful. It can keep roots a bit warmer in winter and much cooler in the summer. During the summer it is preferable that leaves be dry by the time the sun reaches them.

Should I fertilize my new Japanese maple to get it off to a good start?

No. Thorough watering is the biggest help you can give your newly planted maple tree. Furthermore, maples are NOT heavy feeds. If the tree is planted in the landscape, it will not need fertilizer every year. Container grown trees benefit from one or two mild applications of fertilizer in the spring when all risk of frost is over.

When is the best time to plant Japanese maples?

Anytime! As long as you can be sure the tree will be properly watered, you may plant a container-grown maple tree (all our trees are container grown) any month of the year.

Do all Japanese maples lose their leaves?

Yes! Japanese maples are deciduous trees. During October and November maples provide a lovely show of fall color. Then in late November, or December, the leaves drop. Buds start to swell in February and March brings fresh new leaves—in colors that some say rival the show in autumn.

What is a dwarf Japanese maple?

In the winter, branches of maples are clearly visible without the distraction (albeit a lovely one) of leaves. Branching structure largely defines the category `dwarf’ maple.

At Wildwood Nursery we grow 60-70 maples (cultivars of Acer palmatum or Acer p.) that remain compact and small. In 12 years, some will only grow to about 4 ft. (e.g. Acer p. Corallinum, Tama hime, or Yuri hime ). Others, like Koto no ito, Olsen’s Frosted Strawberry or Shidava Gold, reach 8-9 ft. in 12 years.

There is some confusion among gardeners and garden enthusiasts when we use the term `dwarf.’ By way of comparison let’s look at maples in the `dissectum’ category. Although they are not actually dwarf trees, their branches arch out and down. See the image of Acer p. Orangeola with its branches beginning to weep. Their structure is often likened to an umbrella; and they grow wider than tall.

What is the most common cause of failure in growing Japanese maples?

Poor drainage. In questioning customers whose maple trees have not leafed out in the spring, we find that the soil around the roots was very wet and soggy. Plant your tree in soil that is well aerated and you will find these trees easy to grow.

Why are Japanese maples not dropping their leaves this year?

Over the last couple months, homeowners across the state have been calling the Infoline wondering why the leaves never fell from their Japanese maples this fall (Acer palmatum). Although this may seem like something to worry about, it’s a fairly common occurrence, and in most cases is nothing to worry about. The trees are simply exhibiting marcescence, the trait of holding on to dead plant tissue; in this case, leaves. When a tree prepares to shed its leaves, cells between the twig and leaf stem release enzymes that form an abscission layer which releases the leaf. Sometimes leaves form incomplete abscission layers, causing the leaves to stay attached to the branches. This is common for many species such as beeches and oaks.

The long, mild fall of 2017 may have contributed to the maple’s leaf retention. Even during an average fall, Japanese maples are often one of the last trees to change color. It just takes them much longer to prepare for winter than other tree species. The abnormally warm temperatures in the fall that lasted through October, may have caused many Japanese maples to never form the complete abscission layers necessary for the leaves to drop. Thus, when the cold weather finally came, the leaves were still attached to the trees.

Ultimately, you shouldn’t worry too much about those stubborn leaves. What the wind doesn’t remove will be pushed off by expanding buds in the spring.

This was your Question of the Week. Got questions? The Ask UNH Extension Infoline offers practical help finding answers for your home, yard, and garden questions. Call toll free at 1-877-398-4769, Monday to Friday, 9 a.m. to 2 p.m., or e-mail us at [email protected]


Warton’s Bill Blackledge is one of the county’s most popular and sought after gardeners. If it’s green and needs watering, Bill can tell you about it. He has been answering BBC Radio Lancashire listeners’ queries for over thirty years, which means he’s been there nearly as long as the transmitter!

His knowledge is encyclopedic. After training at the under the then Ministry of Agriculture, Bill spent over twenty years at the Department of Biological and Environmental Services at Lancaster University. Now, he’s a regular course tutor at Alston Hall, Longridge and Lancaster Adult College.

For three decades, Bill has travelled the county with fellow judges as a regional judge for North West in Bloom.

So, whatever the problem, we like to think Bill can sort it out… at least that’s the theory!

Zenab Hira asks…

I have an Acer – Bloodgood. It’s in a large pot, growing very well… the only thing is that it’s growing to one side, kind of leaning more to one side, it hasn’t spread evenly. What do I do to make it look fairly even all round without damaging it too much?

Bill replies…

I am afraid Zenab that this quite often happens with Acers. You will suddenly find that one side of the plant is growing extremely well compared to the other section and I am afraid that if there are no shoots growing from the other section of the stem it is going to be very difficult to achieve an even spread.

Barbara asks…

I have a well-established Acer Atropurpureum but this year buds and new leaves are only appearing on about a third of the tree (near the outside). The branches at the centre and back of the tree are brittle and dead. The same thing has happened to my Ribes. Any thoughts?

Die back of Acers often occurs if the soil is very damp and waterlogged during the winter months and last year Barbara we did have above average rainfalls. You will need to cut out any dead shoots and I would also top dress your tree with a general base fertiliser such as Fish Blood and Bone Meal. I am however slightly worried when you say that the same problem is occurring with your Ribes (Flowering Current) and my immediate reaction is to whether your trees have been infected with the Honey Fungus soil borne disease, symptoms of which are a white fungal growth close to the bark near ground level and also shreds of black boot lace fungi around the roots and at the base of the bark along with amber toad stools appearing early autumn time. More information on this disease is available on the “Hedges” section of this website.

Lily Ghandi asks…

I had bought a foot tall Japanese Acer Sangokaku 2 weeks back and placed the pot in the house during daytime and at night time in the porch in order to protect it from frost. However, a few of its leaves started to wilt. I have fed it with Miracle Grow crystals diluted in water. Today when I moved the plant a clump of leaves fell off. I don’t know where I am going wrong as this is my first Acer plant. Please advise me on watering, feeding and position to place the pot in which I intend to grow.

Your Japanese Acer would be far better placed outdoors in a sheltered position Lily and I am sure that it is the contrasting temperatures which is causing your Acer to lose its leaves. You will need to keep an eye on the watering throughout the summer months and feed occasionally with a balanced liquid fertiliser. Hopefully your plant will start to grow both new shoots and leaves.

Eioleen O’Neill asks…

We have a 14yr old acer which has developed grey blotches on the main branches. Could you advise what they are as the tree has started to bloom and we are afraid to apply any sprays.

The growth Eioleen on your Acer tree is most probably lichen with also some algae growth which will not do any serious harm to your tree. This is a very common problem in the winter months especially in very damp and mild conditions and can also be troublesome if your tree is growing in a very shady spot in the garden. It is not necessary to spray during the growing season but when your tree is dormant during the winter period (December/January) it maybe worthwhile to spray the main trunk and branches with a tar oil winter wash which will kill lichen growth. My only concern with using a tar oil winter wash is that it will also kill off natural predators and if your tree is not completely dormant due to the recent mild winters the winter wash can damage the buds. I am afraid that the only other alternative is to gently brush off the lichen growth during the summer months.

Maria Ash asks…

We have recently moved and have a really lovely acer in our garden which is about 8ft tall we don’t know what kind it is but we have to move it, could you please advise us how wide and how deep approx we will need to dig do get a big enough rootball.

If at all possible Maria you would be far better waiting until the autumn time before transplanting your Acer Tree as the tree will then be dormant. If you cannot wait until autumn time I would suggest that you lift your tree as soon as possible before it is actively growing. As the tree is eight feet tall you will need to try and dig out a very large root ball and the chances of success will depend on the size of the root ball that you can physically remove. However if it is possible to get a small digger into your garden you will find that it will be much easier to lift out your tree and will ensure that you get a large root ball of soil. It is important to keep an eye on the watering of your tree during the summer months and you will need to stake your tree to give support until new roots are established.

Daniel Smith asks…

My mum has an Acer, in a large pot (not sure what kind but it seems to be out-growing it), could you please tell me when we can either re-pot it or move it, should it be at a certain time of year? Thank you.

If you are careful when re-potting you could re-pot your mother’s Acer now Daniel. However personally I find the best time for re-potting Acers is early Springtime before they have come into leaf. Acer prefer a slightly acid soil so you will need to use a ericaceus compost.

Heather Drewry asks…

I have an Acer, which is outside. I have been told it has Mealy Bugs on it. I have used Provado Ultimate Bug Killer twice but it hasn’t made any difference, if anything it seems worse. Is there anything else it could be instead? Or is there something else I could use to clear the problem up, as this plant has been with me for sometime and I don’t want to lose it.

Mealy Bug is problem pest Heather on a wide range of plants and you will find that in time Provado Ultimate Bug Killer will control the pest but what you do need to do is give your Acer a thorough spray with the insecticide and spray to run off. The time to spray is early morning or late evening – do not spray during the day or in the midday sun as this will cause scorching of the leaves. There are other insecticides which you can use such a Liquid Derris Plus – which is a natural insecticide – and also Spray Day Insecticide. The important factor is whichever product you use you need to give your Acer a thorough spray to disturb the aphids which are enclosed in a cocoon.

Sue Eaton asks…

My Acer and Magnolia Susan outdoors have a white glue-like substance on them with disc shaped creatures stuck to it. I looked up mealy bug and I’m not sure if it is this as they are outside. I blasted them off with the hosepipe and the white stuff like marshmallows was all stuck to the fence. These are not on the leaves but on the branches and trunks. What could it be please? My magnolia is 15 years old and never ailed a thing although we moved to this garden two years ago and I brought most of my shrubs with me. Please give me the benefit of your experience.

What you are going to have to do Sue is to spray your plant to run off with a systemic insecticide and the one I would use is Provado Ultimate Bug Killer which will kill scale insects and also mealy bug. I would spray your trees early morning or late evening and if it is a bad infestation you will probably need to spray more than once and as explained above you will need to spray to run off using a powerful jet.

Monica asks…

What tree can I plant in a tiny garden which grows no more that 12/15 ft high? Don’t like those narrow column trees; do love autumn colours though.

If you require a plant for autumn colour Monica and your garden is sheltered I would choose one of the Acer Palmatum Cultivars. There are also the Magnolias and Stellata is reasonable dwarf variety. The deciduous tree Amelanchier Grandi Flora will again give you autumn colour and also Prunus Serrula.

Peter asks…

My japanese acer japonica leaves have shrivelled and withered it is a young tree in a pot… what can the cause be? It came out with a flourish but the leaves never looked right.

You will find Peter that all Japanese Acers do suffer badly from wind scorch damage and also the early morning sun can quite easily cause scorching and shrivelling of the leaves. Acers love to be grown in a slightly acid soil and I find they are far better situated in a sheltered dapple shady spot. With regard to your Acer I would situate it in a slightly shaded spot and I am sure that providing you do not over water it will produce new shoots. The biggest problem this year has been the adverse weather conditions which has caused havoc to a large number of plants.

Rosie asks…

My son has just moved into a rented house and there is a lovely red-leaved acer in a pot in the garden. It seems to be losing its leaves – are they deciduous (?) – and we’re not sure how to look after it! The pot is about 14/16 ins across and the acer is about 3ft tall. Help! As it belongs to the landlord we’re panicking!

There is no need for either yourself or your son to panic Rosie your red leafed Acer is deciduous and produces beautiful colours during the autumn time before shedding its leaves. With regard to ‘looking after’ your Acer. Acers love to be situated in a dappled/shady sheltered position and, in early springtime when it starts to come into leaf do ensure that it is protected from prevailing cold spring winds.

Ann asks…

Hi Bill I planted a young japanese acer (Katsura) in the spring and noticed a few days later that the leaves on the tips of the stems were turning brown and withered. Thinking it was settling into its new home, I left it alone. However all the leaves have now died but they have not dropped off in spite of recent heavy rain hitting the plant. Is it possible for an acer to be affected by Fireblight? If not your opinion would be appreciated. P.S Waterlogging has been ruled out, the land has good drainage and other young acid loving plants in the same area are thriving.

Japanese Acers need to be situated in a shady and sheltered position and I am sure that your Acer has suffered from wind scorch damage and the recent extreme weather conditions. I am however sure that when the weather improves your Acer will produce new leaves. Regarding fire blight your Acer will NOT have been affected by this disease.

Gareth Davies asks…

I’ve been keeping japanese acers for 2 years. Planting them in ericacious soil however this year 3 have died. Where am I going wrong and how can I keep and maintain them?

Japanese Acers lover to be grow in a neutral to slightly acid soil Gareth and for the best results Acers need to be situated in a sheltered and slightly shaded position and, the compost needs to be reasonably well drained, they can suffer from waterlogged conditions. One of the problems with using an ericacious soil is that the majority are one hundred per cent peat based which, makes them prone to waterlogging during wet conditions and what I tend to do Gareth is to use a mixture of an ericacious compost with a soil base compost with ten per cent of a sharp grit which assists in avoid waterlogging during the winter months.

Julie Quinn asks…

I have a small Acer tree Orange Dream and now that we are nearing winter, I have noticed the leaves are showing lighter patches and blotches on the leaves as well as curling and crisping. Can you tell me what is causing this and how I can get it back to good health for next season?

Your Acer Tree Julie is deciduous and what is happening to the leaves is natural senescing before they fall. There is nothing to worry about and next spring your Acer will again come into full leaf. If your tree is growing in a container it is important to protect the young leaves from prevailing winds – the leaves can quite easily suffer from burning and wind scorch, and Acers do prefer to grow in slightly dapple shade.

David Collins asks…

Is it normal for acers to shed leaves at this time of year and start producing new growth or is it due to the mild weather (October)?

Acers are deciduous trees David and will shed their leaves during the winter months. With regard to new growth now appearing this has been caused to this year’s unpredictable weather and the very mild autumn.

Kay McCourt asks…

I have an Acer Atropurpureum in a pot about 18″ dia. I have grown it from a small plant and it is about 1.5m tall and potbound. Can it live on in this pot? Should I transplant it ? Our garden soil is clay which is the reason I kept it in a pot. The leaves are looking dried up and have what looks like wind damage.

Acers love to be kept in a sheltered and dapple shady position Kay as this cuts down the chance of the leaves being damaged by wind scorch. With regard to your Acer you will need to add quite a lot of organic material to your soil, I am afraid Acers to not like being planted in heavy clay soil. An alternative to planting in clay soil would be to transplant your Acer into a larger container and there are on the market large wooden and terracotta containers available.

Andy Robertson asks…

I have a beautiful Acer which has been pot grown for over 12 years now. It is currently in a pot about 2 foot deep and 1.5 feet diameter. Over the last two years, despite careful watering, feeding and mulching, the edge of leaves become brown and dry within two months of the new season’s growth. First question, is there anything I can do to prevent this or is it pot bound? Secondly if I was to put it into the ground, when is best time to do it and what preparation would you suggest? I only have very limited space so the final size of the tree would be a consideration if I was to re-plant it into the garden. It’s currently about 5ft high with a 4 ft spread. I hope you can help.

I am afraid Andy that a lot will depend on which species of Acer you have in your garden as some will grow to a height of thirty to fifty feet or even taller. If your Acer is one of the Japanese varieties such as the Acer Palimatum this will only grow to approximately twelve feet high and with the Japanese varieties you will be able to repot into a larger container. It is important for you can find out which type Acer you have before transplanting into your garden. You mention browning of the leaf edges which, does occur frequently when Acers are just coming into leaf and the Japanese Maples in particular like to be situated in a dapple, shady position.

Rebecca MacFarlane asks…

One of my potted Acers turned black and died. On inspection, the soil in the pot is full of tiny jumping insects. Did these kill my tree? The insects can now be seen under the surface of the soil in my other pots how can I get rid of them before my other trees die?

I passed your question on to an eminent Entomologist at Lancaster University and he has stated:

“If these tiny jumping insects are springtails as I strongly suspect (not being able to think of anything else which would be tiny and jump, at least not without a fuller description) they are most unlikely to have been responsible for the death of the plant as they feed on fungal hyphae in the soil.”

Following the above comments it is difficult to pinpoint what has caused your Acer to die back Rebecca – it could be waterlogging of the soil which quite often happens if you use a peat base compost.

Michelle Aston asks…

I have an acer the stems are covered in what looks like mini legless woodlice! They are different sizes and slightly different colours. Apart from this it seems healthy?

It looks Michelle as though your Acer has been infected with a scale insect and I would spray the stems with an insecticide spray and the one I would recommend is Provado Ultimate Bug Killer. You will need to spray early morning or late evening – try to avoid spraying in direct sunlight which can cause leaf scorch.

Karl Green asks…

How do I stop squirrels eating the new buds on my acer pseudoplatanus?

I am afraid that there is not easy answer to your question Karl. N matter how you try to protect your trees the squirrel will find a way of getting to the new buds and I am afraid the only way to protect your trees is by trapping the squirrels and I would contact the Pest Control Department within your Local Authority regarding traps and how to disperse of the squirrels. I am afraid that you are not allowed to set squirrels free in the countryside.

Sheila Revel asks…

I have a four year old acer which is covered in black fly. I have never had this before and it is affecting the new growth of leaves. Why has problem suddenly occurred?

Black Fly has been a problem this year Sheila and I am afraid that you are going to have to spray with an insecticide to control the problem. If you require an organic insecticide I would use Organic Pest Control or another natural insecticide product is Bio Liquid Derris Plus. Do not spray in direct sunlight – I would advise spraying early morning or late evening.

Robert Blackwood asks…

I have Japanese Acer, it’s about 5 yrs old. Has been doing well but last season developed an orange fungus on one of branches. This I cut out but now is at base of plant and one root is covered. My local garden nursery suggested applying surgical spirit to the affected area. This worked briefly but has come back with a vengeance. Is this fungi scale? From RHS description I read it does not appear to be. No mention of orange. The next problem is the wood then dies. It’s a small beautiful tree and I would hate it to die. Also what is best feed for Acer? Thank you

It is difficult to pinpoint exactly what the fungal disease can be Robert but one of the most common diseases, which attacks a wide range of shrubs, is the Honey Fungus (Armillaria) and the symptoms are a white fungal growth appears near the bark at ground level, and on the roots are strands of fungi which are black and are similar to boot laces, and in the Autumn time amber coloured toad stools appear around the base. The other disease which caused die back of branches is Coral Spot where you will find raised pink spots on the branches. You can also get die back of the branches if your Acer is growing in very badly drained soil. With regard to feeding your plant I would use a general base fertiliser sprinkled around the base of the Acer in early Springtime – Fish Blood and Bone Meal or GrowMore are good established products to use. With your infected Acer you will need to cut out any diseased branches and stems.

Does a Late Spring Frost or Snowfall Damage Trees?

When the spring season arrives, everything should feel bright, warm and fresh! That is until winter elements interrupt and delight us with one last freeze (just when we thought we were in the clear).

An untimely temperature dip isn’t just a shock for us. Our trees notice, too.

When typical spring temperatures turn frigid, some trees may experience frost damage. One of our blog readers, Kathy from Ohio, reached out about her beech tree. She asked, “My leaf buds got frosted this spring and died. We had very early temperatures in the 70s then it got seasonably cold. Can the tree be saved?”

Keep reading to learn the answer to Kathy’s question and care tips for trees affected by a sudden freeze.

Will a late spring frost or snowfall hurt my tree?

Frost damage affects all trees in some way. The good news is that for most trees it’s only a small setback, and they can fully recover with your help.

How does a late spring frost damage trees?

Any drastic change in weather can stress out trees, especially if they weren’t ready for it! That’s why if your tree put out new growth as spring arrived, those blooms or shoots could be damaged when temperatures suddenly drop.

Many trees can sprout again later in the season after this disruption. However, flower and fruit trees are particularly vulnerable to frost and may not be able to produce new flowers or fruit for the current year.

How does frost damage affect my specific type of tree?

In general, frost damage will turn the new growth brown a few days after the freeze. Here’s a closer look at how some trees react:

  • Japanese maples damaged by a late frost may have shriveled, black or brown leaves. Those leaves may fall off and eventually regrow (albeit a bit weaker the second time). If your Japanese maple had only buds when hit by frost, they should be OK.
  • Maple tree frost damage causes leaf edges to turn brown or crinkle, but the tree stays strong for the most part. Maples should have no problem with a second sprout when temperatures level out. Similarly, if maple leaves were still just buds, the tree should be fine.
  • Redbud frost damage makes leaves turn brown and wilt. As long as the trees are healthy, they should be able to sprout a new canopy. If the buds were hit hard by frost or snow, they may not bloom.
  • Lilac freeze damage isn’t too common. Lilacs handle cold climates better than most flowering trees, so at worst, you may see a little browning.
  • Magnolia tree frost damage causes broken stems and wilted, blackened leaves. But, with a little care, the tree should be able to replenish its canopy. If flower buds were hit after they began to show color, bloom will likely be reduced. Some buds may still flower (although not as brilliantly) while others might drop pets and look lackluster..

Can you help trees damaged by frost?

Getting back to Kathy’s question, frost-damaged trees can often be saved with some special attention.

Here’s what to do:

  • Trees on the edge of their climatic range are usually more vulnerable to late season frosts. Always plant the right tree in the right place!
  • Check your forecast to track upcoming temperature drops. You can get ahead of it by watering your tree the night before or covering your tree with a breathable material, like burlap, if it is small enough.
  • Once there’s no risk of another freeze, keep the tree stocked with water for the rest of the growing season. Deeply water your tree once a week should do the trick.
  • Mulch your tree to lock in soil moisture. A ring of mulch that’s 2-to-4-inches deep will also provide nutrients for the tree’s new leaves.
  • Prune out any dead stems. Here’s how to tell which ones aren’t making a comeback.

We recently suffered a severe hard freeze after our trees had already leafed out! Will the trees recover on their own, or is there something I can do to help? The leaves are brown and shriveled on all my small ornamental trees and most all shrubs. Please HELP!!!

The first few spring-like days of the year always get me excited. I eagerly anticipate the first blooms of the season
peeking out to brighten the drab winter landscape. But as I gear up for the coming gardening season, I have learned to keep a watchful eye on the weather. In order to clean out the old and bring in the new season, the weather can make some dramatic changes in a very short period of time and so it is a good idea to be prepared.

If your garden is subjected to some unseasonably warm temperatures that have caused some early blooming or leafing
out of your landscape plants and then freezing weather is predicted, you need to jump into action. It’s time to break out the frost blankets, add a couple inches of mulch, move container plants to a garage or enclosed area and make sure everything that needs water is well hydrated several hours before freezing temperatures occur.

Even with all these precautions, there will be times when the frost will still damage the plants.

If you see shriveling, browning or blackening in the leaves or stems of your plants, that is a sign of damage from freezing. There is very little that you can do now except wait as recovery has more to do with the plant and how it
handles the extent of the damage. Healthy trees and shrubs should produce additional growth within a few weeks. For
perennials, as long as roots and crown were not harmed, they will also show signs of new growth in a few weeks. You can check for pliable branches, but wait at least 1 or 2 months after the plant should have come out of dormancy before making a determination whether the roots are dead and you remove it. Pruning will not revive a damaged plant.

The plant will repair itself so wait until new growth appears, and that will guide you where to prune. At that time trim away dead and damaged branches, and to enhance the natural look of the plant.

Japanese Maple Winter Dieback – Symptoms Of Japanese Maple Winter Damage

Winter isn’t always kind to trees and shrubs and it is entirely possible, if you live in a region with a cold winter, that you’ll see Japanese maple winter damage. Don’t despair though. Many times the trees can pull through just fine. Read on for information on Japanese maple winter dieback and what you can do to prevent it.

About Japanese Maple Winter Damage

Heavy snow is often the culprit when your slender maple tree suffers broken branches, but winter damage of Japanese maple can be caused by various aspects of the cold season.

Often, when the sun is warm in winter, cells in the maple tree thaw during the day, only to refreeze again at night. As they refreeze, they can burst and ultimately die. Japanese maple winter dieback can also be caused by drying winds, scalding sun or frozen soil.

One of the most obvious signs of winter damage of Japanese maple are broken branches, and these often result from heavy loads of ice or snow. But they are not the only possible problems.

You may see other types of Japanese maple winter damage, including buds and stems that are killed by the cold temperatures. A tree may also suffer frozen roots if it is growing in a container above the ground.

Your Japanese maple may have sunscald of its foliage. The leaves turn brown after they are scalded by bright sunshine in cold weather. Sunscald can also crack open the bark when the temperatures plunge after sunset. Tree bark sometimes splits vertically at the point where the roots meet the stem. This results from cold temperatures near the soil surface and kills the roots and, eventually, the entire tree.

Winter Protection for Japanese Maples

Can you protect that beloved Japanese maple from winter storms? The answer is yes.

If you have container plants, winter protection for Japanese maple can be as simple as moving the containers into the garage or porch when icy weather or a heavy snowfall is expected. Potted plant roots freeze much faster than plants in the ground.

Applying a thick layer of mulch – up to 4 inches – over the root area of the tree protects the roots from winter damage. Watering well before winter freeze is also a good way to help the tree survive the cold. That kind of winter protection for Japanese maples will work for any plant in the cold season.

You can provide extra protection for Japanese maples by wrapping them carefully in burlap. This protects them from heavy snowfall and frigid winds.

How To Identify Ash And Maple Trees In Winter

During Canadian winters it might be difficult to tell the difference between ash and maple trees when their leaves are gone. You can identify them by observing the structure, twigs, buds, and bark of the trees.


Both ash and maple trees have “opposite branching,” opposed to “alternate branching,” in which the side branches stagger and alternate throughout the branch. Opposite branching trees have branches growing directly opposite each other. The twigs grow in the same pattern on the branches.


Ash trees have robust twigs to support dense clusters of leaflets. Maple trees have individual leaves supported by delicate twigs. A tree with opposite growing branches and big, fat twigs is likely an ash. Trees with opposite growing branches and thin, delicate twigs are probably maples.

Bark and buds

This is another clue to identifying the bark and maple trees. If you know the bark of a particular ash or maple tree, you might be able to use its cracks, fissures, and colours to spot the tree type in wintertime.

  • Ash – White Ash has soft bark that develops diamond-shaped fissures as it gets older. Its brown buds grow inside a leaf scar shaped like the letter C. Green Ash bark is also soft, but the fissures of mature trees are shallower than those on white ash trees. Green ash buds grow from a D-shaped leaf scar. Black ash has bark with very shallow furrows and darker buds.
  • Maple – Red Maple trees have smooth, gray bark that breaks into irregular fissures as the tree ages. Strips of bark often begin to detach from either end and curl outward. The red maple has red winter buds. Silver maples have dense bud clusters. The young bark of a sugar maple often has a mosaic of cracks that look like glazed pottery. As it ages, vertical fissures that have horizontal cracks begin to develop. Thick plates of the bark may also begin peeling on one edge. Sugar maple buds have layers of tiny scales. The striped maple has bright green bark that has vertical white stripes when young and darker, reddish-brown bark and black vertical lines as it matures.

Rather than looking for “maple trees for sale” signs or guessing which tree is which, contact Caledon Treeland at 905-880-1828 and let us help you determine which trees are on your land and which you’d like to purchase.

On November 25, 2016 / Tips

Fall & Winter Care of your Maple Trees

A sapling just before fall dormancy. Wait until leaves are off before planting.

Planting: Fall is a good time to plant saplings (maples or other native species), but it should be done after the sapling goes into dormancy, exhibited by losing its leaves. Fall planting should only be done with containerized stock. Bare root stock will have a much lower survival rate when planted in the fall.
After planting the dormant sapling, remove the summer’s dead twigs and place a thin layer of mulch around the base of the tree. Only water the tree if the soil or root ball appears to be dry. Do not soak or fertilize the sapling.

Remember, Fall is too late to fertilize your trees or new saplings. They are going to “sleep” for the winter months and should not be encouraged to grow at this time by fertilizing or over-watering.

Mulch: Check around the base of the tree. If there is no mulch, add a thin layer of mulch (leaves, wood chips, or other mulch from your local retail nursery) to protect the tree and reduce evaporation. Do not “volcano” the mulch into a pile around the base, this will encourage rotting at the base of the tree.

Pruning: Once the leaves are off, indicating the tree is dormant, prune the tree to make sure there is only one leader (not 2 or 3) and remove unwanted side branches. Remove any dead branches.

Sugar Maples Beat the Cold

Illustration by Adelaide Tyrol

I want to know the secrets of the sugar maples in our woods. I want to know how they survive the winter, naked except for their thin robes of grooved bark. I want to know how they survive the winter when the earth turns to stone and the wind drives needles of ice and snow. And I want to know how next spring’s sensitive new buds, encased in a coif of soft brown scales, survive more than three months of on-again, off-again sub-zero weather.

Like a sweater, bark is our maples’ first line of defense against the cold. Bark consists of two distinct groups of cells: those alive (the inner bark) and those not (the outer bark). The secondary phloem, conduit for transporting the maple’s food, is synonymous with inner bark. Each year, as our maples adds a new growth ring, a foamy layer of old phloem is pushed to the outside. These cells die. The foam hardens into fatty, waxy substances filled with capsules of air and becomes the bark we see that is exposed to the weather. This outer bark provides limited protection from sudden changes in temperature.

But not much. A tree, after all, is not heated from within, and since trees are more than 60 percent water, avoiding internal ice damage is a maple’s biggest winter challenge. How do they do it? The answer is that they rely on water’s ability to supercool.

At -36.6 degrees Fahrenheit, ice will form spontaneously in pure, distilled water. As long as there are no dust particles to serve as nuclei for ice crystals, pure water will remain ice-free until that very low temperature. Our northern trees make a point of keeping their internal water as pure as possible, and hence they can reach -36.6 degrees before freezing. In fact, the northern ranges of sugar maple, American beech, and yellow birch correspond roughly with the isotherm that indicates a winter minimum temperature of -40 degrees Fahrenheit. Beech actually endures a low of -42, sugar maple -45, and yellow birch -49.

These slight differences in cold tolerance are attributed to the antifreeze properties of the respective trees’ intracellular sugars. A hike up Mount Washington or Mount Mansfield quickly confirms this, as first beech and then sugar maple cease to grow. Yellow birch, the hardiest of the three, grows all the way up into the lower end of the spruce and fir zone, an ambassador from another realm.

But pure water and antifreeze aren’t the only tricks up our maples’ sleeves. In August, maples produce abscisic acid, a growth-inhibiting hormone that also increases the permeability of their cell membranes. With the first light frosts of September, the trees’ living cells begin to release water into the empty spaces between cells. When a hard freeze hits, ice crystals will form in these intercellular spaces, while the unfrozen water inside the cells’ cytoplasm continues to migrate toward the frozen water outside the cell wall. As more water leaves, the living cells shrivel like a deflated balloon, further increasing the concentration of dissolved solids within the cell walls. And the higher the concentration of dissolved solids, the lower the freezing point.

Ice crystals sometimes rupture the outer, stiff cell wall, indenting but not puncturing the inner, elastic plasma membrane. If the bottom should fall out of the mercury, however, and temperatures drop below the maple’s -45 degree threshold, as often happens on the cutting edge of the tree’s northern range, ice will form inside the cells. When the plasma membrane ruptures, the cell dies. When too many cells die, the tree dies.

Acid rain is making it more difficult for some trees to withstand cold because acidity strips calcium from the soil and calcium is essential for the proper functioning of cell membranes. Studies on red spruce have found a reduced cold hardiness among trees growing on calcium-depleted soils and among trees whose needles are exposed to acidic fog and clouds throughout the winter.

Some northern trees go one step further and nearly freeze-dry their cells by removing almost all their cellular water until huge crystalline masses of ice crowd the intercellular spaces. The paper birch and red osier dogwood that pepper our wetlands can survive submersion in liquid nitrogen at -321 degrees Fahrenheit and still recover upon thawing.

With the unlocking of spring, intercellular ice melts, water is sucked back into the maples’ cells (and, perhaps, into a waiting sap bucket) and normal metabolic processes resume. At this point, surprisingly, the trees have lost their cold hardiness, and even a minor spring freeze can damage them. Trees that withstood twenty five below in January can be severely damaged at twenty five above in May.

Ted Levin is a naturalist and freelance writer living in Thetford Center, VT.

Michael J. McGroarty
Perry, Ohio Copyright 2011

Should you, do you need to, provide winter protection for Japanese Maples?

Japanese maples planted in the ground usually do not need to be covered.

It depends, but you have to be really careful that you don’t do more harm than good in your effort to protect your plants from the cold. So first, let me explain a little about climates and growing conditions. I’m in northern Ohio, zone 5. It gets cold here. Bitter cold at times, wind blowing, blizzard like conditions. During the winter it’s not unusual for us to see temperatures as low as 15 degrees F. some winters we have days and days of single digit temperatures and possibly a few days around zero or below.

That’s cold.

In this climate I grow Japanese maples and a lot of them. How do I protect them during the winter? For the most part I make little or no effort to protect my Japanese maples against our blustery winter conditions. All of my Japanese maples are planted in the ground and at this time none of them are in containers setting on top of the ground. That’s a really important factor. All plants are almost always happier, and safer when planted in the ground. Providing of course, the soil is acceptable and well drained. Very few plants like soil that is wet and heavy and for Japanese maples wet heavy soil is about the worst thing that you can do to them.

So . . . with that said, are your conditions similar? Is there any reason for you to provide additional protection for your tree or trees? If you are in warmer zone than my zone 5, you should have even less to be concerned about than I do. However, if you still feel that you need to provide extra protection, there are a few things you should know about protecting plants for the winter.


Wrapping plants in burlap will help to keep the wind off them. How much it helps is really debatable and I’ve never wrapped anything in burlap. Some people who have evergreen hedges etc. near the road where they can get splashed with road salt often wrap them in burlap, and at best I’ll say that it can’t do any harm and might help a little. You just have to keep in mind that once it gets cold the burlap will not stop the cold at all, but it will break the wind and help to keep the foliage of the plant from getting dehydrated.

Plants in containers need winter protection.

Here in the north, especially in my little town of Perry and Madison Ohio, we have dozens and dozens of large whoesale nurseries who grow millions upon millions of plants in plastic containers above ground. The potting soil that they use is usually a mix of hardwood bark mulch or pine bark mulch. That growing mix dries out easily! Once of the major concerns for these nurseries when they over winter their plants is keeping the plants moist enough. Even when plants are dormant for the winter, it is essential that the roots receive an adequate amount of water, but at the same time not too much water. They have to be moist, but they cannot be soaking wet.

All of these very experienced wholesale growers use the same techniques and same strategies when it comes to getting their container grown plants safely through the winter. Because they know that they have to cover for the winter the majority of these plants are grown in hoop houses that are completely uncovered during the growing season, the summer, spring and fall months. These “hoop houses” as they are called are not greenhouses. They have no heat, no glass, and they are not covered with clear plastic. Come winter, usually around but not before Thanksgiving they start covering these houses with white plastic. It’s called over wintering film and they use white because the white film actually reflects the rays from the sun.

Read that last sentence again.

They don’t cover their plants to keep them warm. They don’t want them warm. They want them dormant and they want them to stay dormant. So they use white plastic so the temperatures inside the hoop house remain as constant as possible. Does it freeze in there? Yes, absolutely it freezes inside of these hoop houses. The soil in the pots freezes rock hard and the containers freeze to the ground. But once frozen the white plastic keeps things frozen. The worst case scenario is to have the plants freezing, thawing out, heating up then re-freezing. That would be fatal for the plants.

So if you intend to cover your Japanese maples for the winter, keep this in mind.

Use white plastic not clear plastic.

The only time a nursery uses clear plastic is if they are covering a house that is going to be used as greenhouse that is going to be heated day and night. In that case they cover with two layers of clear plastic and then with a little blower they blow a layer of air between the two sheets of plastic. This layer of air is the insulation. But in this scenario the plants are kept nice and warm and they are not dormant. They are actively growing. But that would not be good for Japanese maples because they need to go dormant for the winter. They, like all other deciduous plants need to rest. Winter is when they rest and recharge their batteries for the upcoming spring season.

So in short. White plastic is used to over winter dormant plants and clear plastic is used for growing plants in a greenhouse type of situation.

The lower the over wintering structure the better.

If you decide to build some kind of a structure over your Japanese maples for the winter the lower the structure the better. Yes, wholesale growers use rather high structures. Hoop houses tall enough that you can walk through. The reason that they build their hoop houses so high is because throughout the growing season they have to be able to walk under those hoops as they care for their plants. However, because their structures are high that leaves a lot of air space between the plants and the top of the hoop house. That air pulls moisture from the plants and they have to water at least every two to three weeks, even during the winter. If you don’t water, or can’t water because the water lines are all frozen, the plants will die.

You can and should eliminate all of those issues by building your over wintering structures as low to the ground as possible. Keep in mind that the ground is naturally warm and actually gives off heat during the winter. The closer to the ground you build your structure the more you benefit from that ground heat. That also means less dead air space above the plants and a more effcient use of the moisture inside your structure.

Another trick that I’ve used is to build the structure using two by four lumber and make it flat on top, then pull the white plastic over that. Weight the plastic down on the edges with soil by digging a shallow trench around the structure. By placing soil over the ends of the plastic in the shallow trenches you can pull the plastic really tight, which is very important because if the plastic can move, it will start flapping, tear and blow off.

Of course with a structure that is flat on top puddles of water develop on top of the structure, but then I just take a pitch fork and poke holes in the plastic where the puddles are. The water in puddles drains into the structure, raising the overall humidity inside which is good for your Japanese maples and other plants.

You can also build a low structure using PVC pipe bent in a hoop slipped over top of re-bar that is driven into the ground. However, keep in mind that PVC pipe, or a low flat structure will not hold up to a snow load, so you should install some vertical braces and or keep the snow pushed off the top of the structure. You’d be amazed at some of the structures that I’ve seen come crashing down under snow load. Even large, commercial hoop houses made of steel pipe can and will come down under snow load. It’s usually a combination of crazy winter weather that contributes to these crashes. Snow, freezing rain, more snow, then rain. Things that cause the snow to not slide off of the plastic.

With a flat structure there is no sliding that will take place. You have to be out there with your push broom removing some of that weight. I learned this the hard way. Woke up one morning in early November to the most beautiful, clinging snowfall I’d ever seen. The snow came down so fast that we had 24″ of snow and no electricity before we even got out of bed. By that time my flat structure over my grafted Japanese maples was already down. Fortunately only one end collapsed and it happened to be the end where there were no plants.

It was lesson learned. The two by fours that I used for legs were nailed to the top, not bolted. That allowed them to fold under. But what I really needed was a few verticle four by fours supporting the center of the structure and it would not have come down.

Should I Wrap Trees for Winter Protection?

Wintertime brings out the rawest version of our trees. They’re bare. They’re exposed. And they must survive in harsh, dry air amidst bitter cold temperatures.

So, do they need any help from us to stay warm? Damian in Chicago asked, “Do I need to cover my Japanese maple tree in winter?”

No matter what type of tree you have, here’s when you should step in and protect your tree from winter’s most extreme elements.

What You Need to Know About Wrapping Trees for Winter

If you have a new tree, a tree with thin bark, or an arborvitae, you should wrap it before Jack Frost arrives in town.

Do trees need winter protection? What about evergreens?

Young trees, or trees of any age with thin bark, benefit from winter protection. Why, you ask?

Well, whenever the sun peeks out on a chilly winter day, it warms the tree’s bark. Then, the tissue below the bark perks up. But as soon as the sun disappears behind a building or cloud, the bark temperature quickly drops, which may kill the tissue and can leave the bark cracked and dry.

That, my friends, is what we call sunscald. But if you wrap your delicate trees, you help protect them from it!

A similar scare can happen to evergreens in winter. Their needles soak up the sunlight on warm winter days, but as soon it gets cool again, the foliage can dry out and turn from fresh green to stale brown.

What’s the best tree wrap for winter? Is it burlap?

It depends on what kind of tree you have.

Take Damien’s Japanese maple, for example. It’s a tree that loses its leaves in the fall and has thin bark, so the best way to protect it is by wrapping the trunk in a plastic tree guard.

The same goes for any thin-barked tree, like maple, poplar, aspen, sycamore or linden. Ditto for any newly-planted tree that loses its leaves. Wrap the trunk from the base up to the lowest branches to help protect it from sunscald.

But if you have an arborvitae or evergreen with one of the below issues, wrap it with burlap instead.

Wrap burlap around your evergreen if it’s…

  • Weak for any reason.
  • Fully exposed to heavy wind.
  • Dehydrated and didn’t get much water this fall.
  • Newly planted.

How do I use tree wrap to wrap trees, like arborvitae, with burlap?

There are two ways to safeguard your evergreen tree with burlap. Not only will it help keep the cold air out, but it may also stop deer from eating it!

Option one:

  1. Loosely wrap burlap all the way around the tree, from the lowest branches to slightly above the highest peak.
  2. Pin the burlap temporarily, cut from the spool and remove pins.
  3. To secure, use twine to tie the top, middle and bottom of the tree.

Option two:

  1. Grab three wooden stakes that are slightly taller than the tree.
  2. Place one stake in front, one on the side of the tree that gets the most wind, and the final one on either side of the tree. You want to form a triangle.
  3. Stretch a few pieces of burlap across the stakes and secure with staples.
  4. When you’re done, you’ll have what looks like a protective fence around your tree.

Tips For Winterizing Japanese Maple Trees

As winter approaches your maples are losing their leaves, going dormant and preparing for winter. Typically maples can handle down to -15° F without much trouble, but when Japanese maples are young they may need some protection. The harsh effects from wind and ice are the two most important factors to keep in mind when protecting your trees. Here are some tips to consider for winterizing your maple if you live where there are particularly severe winter conditions.

1) Choose sites out of the wind as much as possible. You can minimize weather problems by picking a good planting site with stable temperatures. Planting near buildings helps stabilize temps – but look out for snow drop from roofs!

2) Do not fertilize into late summer. Make the last feeding of the season at least two months before you expect the first frost. Go light and use low amounts of nitrogen to limit damage to new growth.

3) Water heavily just prior to freeze-up. If autumn rains have been insufficient, give your plants a deep soaking to supply water to the entire root system before the ground freezes. Deep soaking will help to guard against water loss in winter.

4) Mulch to insulate the roots with a 3-4 inch-deep pile of mulch built around the base of the tree. Place the mulch 6 inches away from the trunk. Extend the mulch spread 2 to 3 feet beyond the drip line, (the tree’s outermost branch). Make the mulch ring with dead leaves, bark, wood chips or compost. This keeps freeze damage to a minimum.

5) Wrap Japanese maples with burlap (if you experience heavy snows or prevailing winter winds) for at least the first three years. Snow falling in the colder climates can both protect and endanger plants. A good snow cover will insulate the soil similar to a mulch. However snow accumulating on Japanese maple branches will weigh them down, risking breakage.

To properly wrap your tree begin by preparing the smaller branches and twigs before they freeze and become brittle and prone to breakage. Tie one end of a rope around the base of the tree and encircle the crown of the tree with the rope from the bottom up, reaching as high as possible. Tighten the rope, pushing the branches close together. Cover the Japanese maple with a sheet of burlap from the top down. Fasten the burlap wrap with rope or heavy-duty duct tape. Alternatively, slip a burlap sack over the roped crown. Since your trees are small, it would be best to use a stake to help support the burlap. If your trees are in more exposed locations, wrap every year.

6) Leave potted maples outside until the temperature regularly drops to below 30° F, then protect by bringing them inside to a cold garage or under a porch close to the house. If any maples leaf out before the spring, put them under a grow light; but be careful when transferring them back outside because the leaves have to be eased into full-strength sun and weather.

7) Water only when they are almost completely dry. Maples do not need much water in the winter since they are dormant. There can be the tendency to overwater your maples in the winter and this can lead to root rot problems.

Winterizing your trees in cold climates can help ensure your tree’s survival through a harsh winter as well as help your tree get off to a great start in the spring.

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