- What’s Killing the Japanese Maples?
- When Do Tree Leaves Come Back in Spring?
- When Do Trees Leaf Out (By Region and Leaf Out Dates)
- What makes leaves sprout in the spring?
- No Leaves On Crepe Myrtle: Reasons For Crepe Myrtle Not Leafing Out
- My Crepe Myrtle Has No Leaves
- Leaves of Crepe Myrtle Not Growing on a Few Branches
- Q&A: Japanese Maple looks like it is dying
- Why did my Japanese Maple not leaf out this spring?
- Has my Japanese Maple completely died?
- Why Japanese Maple Won’t Leaf Out – Troubleshooting A Leafless Japanese Maple Tree
- Japanese Maples Not Leafing Out
- Reasons for Leaves Not Growing on Japanese Maples
What’s Killing the Japanese Maples?
November 21st, 2016
It’s pretty obvious what’s been killing our hemlocks (woolly adelgids), our ash trees (emerald ash borer), and our Douglas firs (needlecast disease).
A lot of Japanese maples have been mysteriously dying in the last 2 to 3 years.
What’s not as obvious is why so many Japanese maples have been struggling the past 2 to 3 years.
The trees I see are dying slow deaths. A few branches go leafless and die here and there until there’s nothing left after a few years.
A fungal, soil-borne disease called verticillium wilt is behind some of the demise, and so, too, is the erratic weather we’ve been having. But beyond that, there’s no single, blatant explanation for why so many of these beautiful specimens are biting the dust. Worse, there’s no quick and easy fix to make it stop.
Japanese-maple death has been going on to some degree for decades, but I started getting a lot more reports about 3 years ago. That coincided with the arrival of a January “polar vortex” – the fashionable term for a blast of sudden and brutal cold from the North.
I wrote off that trouble as an isolated winter-weather killing event.
But then another round of death and dying happened 2 years ago – this time what I suspected was related to a long string of unusually warm fall weather followed by a sudden temperature nosedive that zapped trees before they had a chance to prepare for cold.
That fall, Japanese maples never did put on their usual glorious red fall-foliage show. The leaves went straight from green (or in-season burgundy) to brown, and they failed to drop in mid-fall as they should’ve.
The fall before last, a sudden chill turned Japanese maple leaves brown before they had a chance to turn color.
This year, we didn’t have either of those. But we did have a relentlessly rainy May followed by a very dry summer in most areas. That’s potential double trouble for Japanese maples.
Japanese maples hate “wet feet,” so a combination of poor drainage and rain like we had in May can encourage a soil-borne fungal disease called phytophthora. This disease can kill trees branch by branch.
Japanese maples also hate drought conditions, and parched soil like so many of us had this summer can lead to leaf-margin browning, leaf curling and in bad enough cases, total leaf drop.
If all of that sounds like Acer palmatums might be a tad fussy, you’re right. I think Japanese maples are the finickiest of maples to grow, especially the lacy, thin-leafed “dissectum” types that also are especially beautiful.
I’ve concluded that getting them planted the right way and in a suitable spot, then giving them the right care is the difference between thriving and death.
Start by picking a part-shade spot that doesn’t get blasted by full afternoon sun. This limits heat and drought stress as well as the “bleaching” that excessive sunlight causes to the thin leaves. Burgundy ‘Bloodgood’ types look more washed-out brown to me in a hot late summer than burgundy.
If you’re going to plant in full sun, figure on having to water in hot, dry weather.
When siting, also look for a wind-protected spot, such as a courtyard or along the east side of a fence, building or evergreen windbreak. This keeps wind from drying the thin leaves and heads off the leaf tip burn that’s common from cold early-spring wind soon after the tender leaves first appear.
Good drainage is incredibly important in discouraging root-rot disease and encouraging good root growth that makes the tree less susceptible to drought stress.
Consider planting Japanese maples “high” in a mounded bed as Hampden Twp. gardener Hylton Hobday has done with this crape myrtle.
I’d always recommend working a couple of inches of compost or rotted leaves into the planting soil, but in lousy clay, I’d go so far as to “plant high.”
That means building a planting mound about 8 to 10 inches high and planting so that the top half of the root ball is above the surrounding grade. Make sure the whole rootball is covered with soil, but don’t pack it up against the trunk.
After planting, top the bed with 2 to 3 inches of organic mulch. Bark, shredded hardwood, wood chips or a combination of leaves and chipped branches are four good options. This holds down weeds, but more importantly, slows evaporation loss from the soil.
In a hot, dry summer, give Japanese maples a deep soaking once a week. For new or “newish” ones, twice a week is better.
All of this is aimed at keeping your Japanese-maple roots damp but never soggy.
Too much or too little water can be deadly by itself, but water extremes also are directly related to diseases – too much in the case of phytophthora and too little in the case of verticillium.
One thing not to do? Over-fertilize. Japanese maples are fairly light feeders, and they usually do fine with no supplemental fertilizer. You’ll actually make things worse if you try to fertilize a Japanese maple being stressed by something else (drought in particular). Only fertilize if a soil test tells you you’re lacking a specific nutrient.
Bugs occasionally are a factor. Microscopic nematodes, for example, can injure roots and make trees more vulnerable to verticillium wilt. That’s a very hard one to diagnose.
Scale is the most likely potential killer, and it’s much more obvious with the white, hard flecks you’ll see stuck to branches.
The bottom line is, a happy Japanese maple is a healthy Japanese maple. Or in other words, the more right things you can do, the less you’ll have to worry about a mysterious decline.
This entry was written on November 21st, 2016 by George and filed under George’s Current Ramblings and Readlings.
RSS 2.0 | Trackback.
When Do Tree Leaves Come Back in Spring?
There is nothing better than seeing trees flaunt fragrant flowers and green, glorious leaves in spring!
So, when will they sport their fresh new look?
While there’s no set date for all trees to break bud, we can use clues to predict when trees typically leaf out.
Find out when to expect spring tree sprout in your region and if you should be concerned about a late bloomer.
When Do Trees Leaf Out (By Region and Leaf Out Dates)
There are two ways trees know when trees wake up for spring. First, they respond to noticeably warmer days after a stretch of cold temperatures in winter. At the same time, they react to a change in light duration, when shorter nights and longer days of sun exposure, spur new growth and development.
At Davey, we use the Davey Nature Clock, a patent-pending software application that predicts bloom time and peak pest emergence. Utilizing weather data from over 400 locations across the nation, the Nature Clock helps to achieve more precise timing of pest management applications.
While the Davey Nature Clock’s predictions are specific for each year, species, and location, we can use it to generally predict when trees bloom.
Below learn when trees will typically leaf out and bloom in your area. And remember, if there’s unusual weather in your area, like a mild or severe winter, trees may bloom sooner or later than this.
- Leaf Out Dates in the Midwest: Expect tree bloom in the Midwest when warmer temperatures get on a steady schedule, around mid-April.
- Leaf Out Dates in the Northeast: Northeastern trees are adapted to take extra caution when it comes to spring bloom since it can be devastating for leaves to be shocked by a sudden freeze. Because of this, trees in the Northeast bloom late April to early May.
- Leaf Out Dates in the West: Western tree bloom can vary widely. From coastal California to mountainous Colorado, trees are exposed to a number of different climates. Expect western trees to bloom fully by early May.
- Leaf Out Dates in the South: Trees native to the South are well-adapted to the region’s warmer weather, so they don’t stay dormant for long. Trees in this region bloom as early as mid- March.
What if your tree is not growing leaves in spring?
If you’ve noticed trees around the neighborhood blooming while yours is barren, don’t panic! Just because spring is in full swing doesn’t mean your specific trees are ready to bloom or leaf out.
For example, some trees, like birch and willows, bloom early to lengthen their pre-summer food production time. On the other hand, trees, like oaks and elms, prolong their bud break to protect against sudden drops in spring temperatures early on.
As long as tree buds are green on the inside, they’re alive and well—just waiting for their time to sprout. If you don’t spot buds or the buds are shriveled or black, that could indicate it’s a problem.
What makes leaves sprout in the spring?
A spring sycamore with buds opened and flowers appearing. Credit: Albert Bridge, geograph.org.uk
If youre in the lower latitudes of Canada right now, take a look outside. Most trees are in the process of sprouting their 2011 crop of leaves. Only a few weeks ago, they appeared barren now there is an explosion of new life.
But how does this happen? As internationally acclaimed plant biologist (and Vice-Principal, Research at U of T Scarborough) Professor Malcolm Campbell explains in this interview, this bursting of buds is the result of a complex program designed by the trees over tens of thousands of years. It all depends on a number of factors occurring throughout the year and variation in one factor can change the timing of trees buds bursting in the spring.
What is it about the spring that makes the new growth of leaves on trees occur, year in and year out?
Its actually two things.
Even though were in the spring now, the whole program that youre observing was set up in the autumn.
As the days get shorter in the autumn and the temperatures decline, the tree sets itself up to go dormant and then in the same program sets itself up to burst bud in the spring. And of the two components I mentioned, day length and temperature, the one in the autumn thats most important is day length.
That functions as a signal for the plant to begin to shut down. Actually, to put it another way, its night length thats important. As the nights get longer, the plant perceives the lengthening night or the shortening day and embarks on a program to shut down.
That said, even plants in tropical zones or in lower latitudes will still shut down in the winter months, even though the day length may not decrease as dramatically as what we experience in Canada. And they do that by perceiving other cues. Decreasing temperature is one cue. Water availability is also important. Take a look at forests that exist close to the Equator they use signals that are derived from water availability. So in late August and early September in the northern hemisphere, when precipitation rates drop, that can function as a cue and have the tree shut down and enter that dormant state.
When the trees make that dormant bud, that hardened bud we see through the winter months that protects the growing tissues underneath from the foul weather, they are set up to grow again in the spring and to make sure they interpret the cues during the winter so that they dont grow again in the spring at the wrong time.
Why is there variation in when the leaves sprout from year to year? My wife noted in 2010 that all the leaves had come in on May 1. This year, its mid-May and the trees are not fully in bloom yet. Why?
Let me provide a bit of background first.
The program that is set up is contingent on having whats called a cold requirement. That is, having a minimum number of days of cold temperature. After this critical number of cold days has passed and, provided the plants are warmed to an adequate temperature, they will burst buds in the spring. Both factors are essential.
This explains why trees from lower, warmer latitudes dont do well in cold climates. What will happen in cold climates is that their need for cold temperature or reduced water will be fulfilled very rapidly and you can imagine that you might have a very warm day in January and what will happen is that those trees will burst bud and then well have a cold snap after that and it will kill them.
Weve seen this before, even in Canada, for trees at lower latitudes, especially those running along the Canada-US border. In the 1930s, the trees had their minimum requirement for cold days fulfilled and the temperature rose relatively early in the spring. The trees burst bud and they were making leaves and then there was a cold snap and we had a catastrophic loss of trees due to fulfilling the cold requirement, having a warm time and then having a late spring frost again.
So, to answer your question, in 2010 the buds may have burst two weeks earlier than this year because the autumn of 2009 was cold enough for the trees. So, once the night length got longer, the trees went into their dormant program, and then the tree was able to fulfill its cold days requirement and then there were enough warm days to allow the tree to say, OK, timing is right, I can burst bud again.
And what happened this year to make them burst bud later?
There could have been a warmer autumn last year. Warm autumns can mess the plants up. As I recall, it was a warm autumn last year. This is one of the things that people are worried about with global climate change if we have warmer autumns, that cue wont be there to tell the tree to go dormant in the autumn and they wont have the necessary combination of day length and temperature to properly shut them down.
This is what could have happened this year. The other cue is that we didnt have sufficiently long enough numbers of warm days on the spring side to bring them out of dormancy. So their cold requirement might have been met during the winter, but now we havent had enough warm days in a row to bring them out of dormancy. So, everything is delayed. Remember, trees wont do anything until they get their cues.
Is it possible for trees to adapt to what we expect to be the vastly different climate conditions global warming will bring about?
It is true that trees can adapt and have adjusted to pretty significant climate changes in the past.
For example, during the last period of glaciation, we had many of the tree species familiar here in southern Canada pushed down into southwest California and the Florida panhandle, as the ice sheet pushed from north. That took 10,000 to 15,000 years. Herein lies the problem today while it is true that over long geological time scales plants and animals can adapt, if youre talking about a tree that doesnt have the capacity to pick up and move long distances, then climate change that takes place over a very compressed time scale can make it very difficult for the tree to contend with.
U of T is doing a lot of research in understanding life systems of trees and plants, isnt it?
Yes, weve made some important discoveries. One is by U of T professors Peter McCourt, Darrell Desveaux and Nick Provart of Cells and Systems Biology and a former U of T professor, Sean Cutler. This group has reached an understanding, at a very detailed level, of the mechanism that perceives hormones that tell the plant OK, now its time to shut down.
My own lab has been working on understanding all the genes that are expressed in response to cues like that but weve been focused on a different cue not temperature but water availability. To put it more simply, were working to understand the molecular pathways that control the plant processes that we see change around us, like the leaves dropping and then growing again.
Its interesting how this work, in the study of trees and plants, sounds similar to work done on human health.
Absolutely. The tools were using to investigate personalized medicine or translational genomics, which are so important to humans, are the same tools being used to understand and protect forest and crop health.
Procrastinators get more efficient with holiday shopping as deadlines closes in Provided by University of Toronto Citation: What makes leaves sprout in the spring? (2011, May 17) retrieved 1 February 2020 from https://phys.org/news/2011-05-what-makes-leaves-sprout-in.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
No Leaves On Crepe Myrtle: Reasons For Crepe Myrtle Not Leafing Out
Crepe myrtles are lovely trees that take center stage when they are in full bloom. But what causes a lack of leaves on crepe myrtle trees? Find out about why crepe myrtles may be late leafing out or fail to leaf out at all in this article.
My Crepe Myrtle Has No Leaves
Crepe myrtles are one of the last plants to leaf out in spring. In fact, many gardeners worry that there is something seriously wrong when the only problem is that the tree’s time just hasn’t arrived. The time of year varies with the climate. If you don’t see leaves by mid spring, check the branches for tiny leaf buds. If the tree has healthy buds, you’ll soon have leaves.
Is a crepe myrtle tree appropriate for your climate zone? Crepe myrtles are suitable for temperatures in U.S. Department of Agriculture plant hardiness zones 6 or 7 through 9, depending on the cultivar. When winter temperatures are too cold or when you have a freeze too late in the year, leaf buds can suffer injury. In areas that have no freezing temperatures in winter, the tree doesn’t receive the expected signal that winter has come and gone. Crepe myrtles need freezing temperatures followed by warm weather so that it will know when to break dormancy.
If your crepe myrtle is not leafing out, check the buds. Remove a leaf bud and cut it in half. If it is green on the outside but brown on the inside, it has suffered cold damage from late freezes.
Buds that are brown all the way through have been dead a long time. This indicates a chronic problem that may have affected the tree for years. Scrape off some of the bark near the dead buds. If the wood under the bark is green, the branch is still alive. If you find dead wood, the best treatment is to cut the branch back to the point where the wood is healthy. Always make cuts just above a bud or side branch.
Crepe myrtles make lovely street trees, so we often plant them in the space between the road and the sidewalk. Unfortunately, trees planted in this location suffer a lot of stress that can inhibit crepe myrtle leaf growth. Stress factors for crepe myrtles used as street trees include heat, drought, soil compaction and environmental pollution such as salt spray and car exhaust. Frequent watering can reduce the amount of stress on the tree. You should also remove root suckers and weeds in the immediate area to prevent competition for nutrients and moisture.
Leaves of Crepe Myrtle Not Growing on a Few Branches
If only a few branches are failing to leaf out, the problem is likely a disease. Diseases that cause leaf bud failure in crepe myrtles are rare, but they are sometimes affected by verticillium wilt.
Treatment for verticillium wilt is to cut back the branches to a point where the wood is healthy. Always cut just above a bud or side branch. If most of the branch is affected, remove the entire branch without leaving a stub. Many people feel that pruning tools should be cleaned with a household disinfectant or bleach between cuts when dealing with diseases; however, recent studies show that unless the plant has oozing wounds, disinfecting is not necessary, and disinfectants are likely to damage your tools.
Q&A: Japanese Maple looks like it is dying
Q. I think my Japanese maple is dying.
The height of the tree is approximately four metres and it started out with deep purple palm-shaped leaves. In the beginning of spring, when new leaves came out, some of the tips of the branches did not produce any leaves. After May, I noticed leaves started to dry and fall off. Now it looks like all the leaves are drying out. I think the tree is dying. I tried watering and feeding the tree some Miracle-Gro to revive it, but there is no change in its condition. Please advise how I can save this tree. Brampton, Ont.
A. Japanese maples have several growing conditions, which should be met in order for them to grow well.
They require moist, well-drained soil high in organic matter, and protection from sweeping winds and late spring frosts. Dappled shade is ideal for these trees, as too much sun can scorch the leaves. The young foliage is highly sensitive to cold, and if leaves come out early, growth can be lost due to frost. In the case of your tree, perhaps the leaves were affected by frost, which may have cause them to dry and drop off. Very often you can lose a year’s growth when this happens, but very rarely is there a loss of the tree. Your tree may also be in too much bright light, and this would also dry-out the leaves. Continue providing supplemental moisture to your tree and if you have not already done so, mulch could be placed around it, which would help to conserve water. In the fall, before the onset of winter, give your tree plenty of water to prepare it for the months ahead. I hope that this information is of help to you, and that you will enjoy the beauty of your Japanese maple for many years.
Zone 5 director
Master Gardeners of Ontario.
|To find more articles on our website that deal with Japanese maples, simply type the word japanese into the search box in the top right corner of this screen and hit the ENTER key on your keyboard (or click the magnifying glass icon) to get a list of articles.|
Japanese maples (Acer palmatum) grow quite well in our climate here in Ontario. The most important thing is to select a sheltered planting site that is out of the severest northwest winter winds. They grow well in any well-drained soil, like full sun to almost full shade, and will do best with protection from the hot mid-day sun. However, it sounds as if your young tree experienced some form of trauma, which could either be, lack of water in the pot or winter damage due to lack of protection over the winter.
In order to avoid winter damage ensure the tree is well wrapped with burlap over the winter months for at least the first three years in the garden. Continuous watering until freeze-up will help to guard against water loss in winter. An extra heavy layer of mulch will also help to protect the root system from any freeze/thaw cycles during the coldest months.
It appears that you have replanted the tree recently so continue to water every day or so and mulch the entire area with a two-inch layer of organic mulch (compost, wood chips or bark) to ensure water retention, to keep the roots cool and deter weed competition.
Once established, Japanese maples may be lightly fertilized only in the early spring (April) with 4-12-8 fertilizer or 15-30-15 water soluble mixture. Major structural trimming may be done during the winter or before the new leaves unfurl in spring. Lighter pruning can be accomplished any time in June after the first major flush of growth begins or in the early fall.
Hopefully your tree will survive.
For more information please read this Master Gardener Factsheet:
Why did my Japanese Maple not leaf out this spring?
In 2012 or so I “rescued” a Japanese Maple sapling that had been thrown into the woods along with several other trees still in their plastic containers by an unscrupulous developer who discarded leftover landscaping following completion of a subdivision. Although it was barely alive, I planted my “rescue maple” and nursed it tenderly. It practically doubled in size over the next four years, from about three feet tall to almost six feet now, although it is still very much a sapling. It has been robust and fully leaved each year since. But last fall the tree didn’t lose its leaves in the fall. And this spring it never leafed out. A few of last fall’s leaves are still gray and curled on the branches. When I researched the internet about the problem several weeks ago, several suggestions ranged from lack of water to a parasitic infestation, but I have not had to manually water this tree since its first year and close inspection shows no borer activity or other evidence of infestation that I could recognize. The tree is not dead, as there is robust leaf activity at the base of the trunk on the ground. There is some evidence of deer rutting on the trunk, but nothing that girdles the tree completely. The tree is near to, but not within, the drip line of a black walnut, so I don’t think the maple’s malaise is from black walnut toxin. I have a baby fig tree a lot closer to a black walnut and it leafed out beautifully this spring. I live in Owings Mills on two acres of largely undisturbed land in a home that was constructed in 1862. When the USGS needed a soil sample in the vicinity of Soldiers Delight (I live on the northeast corner of Deer Park and Lyons Mill roads), they chose my property since my land is largely the way it was 150 years ago. When I bought the house in 2001, a Bing cherry tree was in the location of the Japanese maple, but after my first year here the cherry stopped producing and eventually died, as did a pear and two apple trees on the property. I surmised at the time that the fruit trees were all planted when the house was built in 1862 and had simply reached the end of their lifespans, and I still believe that to be the case. The Japanese maple gets strong morning light and dappled sunlight the rest of the day from a pair of giant oak trees that grace my front yard, one of which is in contention to be the third largest white oak in Maryland. My yard was certified as a Baywise garden in 2015, so there are no pesticides or fertilizers that could be impacting the Japanese maple. I work at home if anyone would like to stop by and take a look at this remarkable piece of property. I am attaching some photos of my little acer. If you can call me or email with any suggestions of how to rescue my “rescue maple” from the brink of whatever is afflicting it, I would most appreciate your help. Thank you! .
Has my Japanese Maple completely died?
Hot Network Questions
- Does the homotopy category of spaces admit a weak generating set?
- Can I publicly release plagiarised source codes someone gave me?
- Assigned to a buggy, failing project days before it is due
- Real rootedness of a polynomial
- Can I be charged for murder if I throw peanuts at someone who has a severe peanut allergy and they die as a result of that?
- What does ‘$ mean in bash?
- Can I delay my turn to the end of a round, by not rolling for initiative?
- What would be a legit sounding medical term for Spontaneous Human Combustion?
- Demystifying Seirawan-Kasparov 1983 king and pawn endgame
- GPU struggles only in the primary PCIe slot. Is this a motherboard issue?
- Purpose of ‘bore’ on spoke nipples – why are spoke nipples not threaded through their entire length?
- How can merging two sorted arrays of N items require at least 2N – 1 comparisons in every case?
- How to tell potential players to pick up their game
- Is it considered bad practice to use company name as part of an SSID?
- How to eliminate rows and columns of matrices?
- Given fluids expand non-linearly how were physicists able to make a linear temperature scale?
- What is a good way to find some other western friends in a foreign city?
- How do I handle a “fake” co-author?
- Match Exec failing to execute anything
- Walk home one step at a time
- Can the Actor feat allow a character to effectively speak a language they don’t know?
- Regional idioms for sunshower?
- What should a pilot flying IFR in IMC and on final, do if the vacuum system fails?
- “Work in a power plant”, “work on a power plant” or “work at a power plant”?
more hot questions
Last week I wrote about spring leaf-out. Yes, I realize that plants vary in terms of when they decide to welcome spring, but why are my beloved Japanese maples taking so long?
I didn’t include death among the reasons why plants fail to leaf-out.
How do you know if a tree or shrub didn’t make it through the winter? It’s still May. No leaves yet on the linden or the locusts. But they’re always slow. The rest of my maple trees have leafed out. Why are only the Japanese maples still just sitting there?
OK, there are some signs of life. A few buds have opened. A few leaves have sprouted on the lower trunk.
According to the experts, these are positive indicators. So, what to do now?
Slow leaf-out signals that a tree is under duress. Water it well, sing it a soothing lullaby, then think back on whether the tree might have been traumatized by a bout of unusually cold or windy weather.
Buds exposed to high winds can be killed. If the buds on your tree are brown and crispy looking, they may have suffered wind damage.
If the damage is limited to part of the branches, you can encourage regrowth by pruning the dead limbs and stems. This way the tree’s roots will send nutrients and water only to the healthy portion of the tree instead of wasting valuable resources on a hopeless cause.
How do you know for sure which tissue is alive and which is dead?
This is easier than it sounds.
Green is good. A traumatized tree can survive if the ratio of green to black is high. Look for a greenish tinge on the bark. On stems and branches that appear lifeless, scrape the bark with your fingernail. If there’s green tissue below the bark, the tree is alive and just needs time.
The same test can be done with leaf buds. Cut into a brown bud. If it just falls off, forget about it. A healthy bud will fight back.
This is also true of a healthy twig. Snap off stem ends. If you feel no resistance, move up the stem until you do feel resistance and see green tissue inside.
If the only part of the tree that seems likely to leaf-out is the lower trunk, it is possible to make a new tree out of the old one by pruning the canopy to a single branch that will become the new central leader. It will form a new canopy … eventually.
This is not advisable if what’s sickening the tree is an actual sickness, as opposed to an external factor such as inadequate sun or water or too much cold or wind.
The most common illness to afflict Japanese maples is verticillium wilt. It’s best to remove the tree so as not to encourage the illness to spread to other innocent victims.
Otherwise, be patient. If the tree is still recalcitrant in early June, you’ve definitely got trouble. Until then, hold tight and think positive. One thing I’ve learned over decades of gardening is that plants behave mysteriously most of the time, especially after a long, hard winter.
Given the fact that we experienced a “bomb cyclone” just a few weeks ago — this is the name weather people gave the triple whammy of snow, rain and high winds that ravaged the state in April — maybe it’s not so surprising that a marginally hardy Japanese maple would be reluctant to expose tender new growth to another one.
I should mention that many people assume they can’t grow Japanese maples unless they’re willing to store them in the garage over the winter. If you want the kind of Japanese maple that has lacy to almost thread-like leaves, then the winter storage routine is still de rigeuer. I know lots of fanatical gardeners who dig up all their Japanese maples in the fall and pot them up, and a few who just leave them in their containers all the time, moving them about on a whim using hand carts.
Because I, too, tend to treat my plants like furniture, this idea appeals to me. If I had more space in my garage and a stronger back I would do this. The plants I bring in, and literally treat like so many sofas and coffee tables, are mostly tropical varieties.
Unlike the potted specimens I overwinter in my house, Japanese maples prefer a cooler winter habitat because they, unlike tropical trees, must have a dormant period. This is when they drop their leaves and hunker down. I lost two brush cherry topiaries over the winter because I refused to let them have their annual winter rest and instead placed them in a sunny window and watered them. They just wore out. Their leaves turned brown and began falling off until it was too late to save them. Lesson learned.
My Japanese maples have endured more than a dozen winters outdoors. The trick is picking the right variety. The hardiest of the species, Emperor, has large, dark red leaves that turn fiery crimson in fall. Most of us associate Japanese maples with a more finely cut leaf, but this trait is associated with a tender temperament, unfortunately.
I grow Acer palmatum “Bloodgood.” To my eye it’s the prettiest of the clan that is also hardy to Zone 5. My trees grow in a fairly sheltered part of my garden, away from harsh winds.
I prune them heavily to encourage a horizontal habit. They want to grow to 15 feet, but I keep them to less than 5 feet tall.
Over-pruning can kill a tree. It’s critical that you leave enough of the tree alone to keep the ratio of root to canopy in balance. The rule of thumb is never remove more than a third of the plant’s top growth.
I’ve killed trees by overdoing it and worried that this was the cause of this spring’s slow leaf-out. A better bet, though, is that bomb cyclone.
Why Japanese Maple Won’t Leaf Out – Troubleshooting A Leafless Japanese Maple Tree
Few trees are more charming than Japanese maples with their deeply cut, starry leaves. If your Japanese maple won’t leaf out, it’s very disappointing. Leafless Japanese maple are stressed trees, and you’ll need to track down the cause. Read on for more information about the possible reasons you see no leaves on Japanese maples in your garden.
Japanese Maples Not Leafing Out
Trees not leafing out when they’re supposed to almost certainly cause alarm in homeowners. When this happens to trees prized for their foliage, like Japanese maples, it can be especially heart wrenching. If winter has come and gone, you look to your Japanese maples to start producing their beautiful leaves. If, instead, you see no leaves on Japanese maples in spring or early summer, it is clear that something is amiss.
If your winter was particularly brutal, that might explain your leafless Japanese maples. Colder than normal winter temperatures or bitterly cold winter winds can
cause die back and winter burn. This can mean that your Japanese maple won’t leaf out.
Your best course is to prune out dead or damaged branches. But be careful because some branches and shoots look dead but aren’t. Do a scratch test to look for green tissue. When trimming back, prune to a live bud or a branch union.
Reasons for Leaves Not Growing on Japanese Maples
If you see only leafless Japanese maple in your garden when other trees are in full leaf, check to see what the leaf buds look like. If the buds do not seem to be processing at all, you’ll have to consider the worst possibility: Verticillium wilt.
The nutrients that leaves produce during the summer are stored in the roots. In spring, the nutrients rise into the tree via sap. If your tree has a problem getting the nutrients back up to the branches, the problem could be Verticillium wilt, an infection in the xylem layer that blocks sap.
Prune out a branch to see if Verticillium wilt is the cause of your Japanese maples not leafing out. If you see a ring of dark on cross section of the branch, it is likely this fungal disease.
Unfortunately, you cannot save a tree with Verticillium. Remove it and plant only trees resistant to the fungus.
Water stress can also be a reason for leaves not growing on Japanese maples. Remember that these trees need water not just in summer, but in dry springs and falls as well.
Another reason for leaves not growing on Japanese maples can be root related. Girdled roots can cause leafless Japanese maples. Your tree’s best chance is for you to cut some of the roots, then be sure it gets enough water.