When to prune trees?

Pruning Ash Trees: When And How To Prune Ash Trees

Ash trees are popular and attractive landscape trees. However, pruning ash trees is essential if you want healthy, vigorous specimens. Cutting back ash trees appropriately helps to establish a strong branch structure around a central leader. It can also reduce diseases and limit pest damage. Read on to learn how to prune ash trees.

Reasons for Pruning Ash Trees

Ash trees are handsome deciduous trees, native to North America. They offer attractive, rounded crowns in the growing season and beautiful autumn colors. The wood is hard but agile, and most baseball bats are made of ash.

Ash trees have an opposite branching structure. The opposing branch growth usually requires pruning to keep the tree balanced. In addition, the tree can be attacked by diseases and pests that can be controlled by pruning.

Cutting Back Ash Trees

Trimming your tree is not difficult, but it helps if you follow a few ash tree pruning tips.

When to Prune Ash Trees

When to prune ash trees depends in part on why you are making the particular pruning cut.

Unless you are pruning to remove dead and diseased branches, you should take care to prune in late winter, while the tree is still dormant. For example, if you must remove live branches to allow additional sunlight and air to circulate inside the tree crown, wait until winter to act.

Prune out broken, diseased, infected or dead ash tree branches whenever you spot them. The sooner you remove these branches, the less likely it is that decay-producing fungi will spread to other areas of the tree.

When you inspect the tree for problem branches, be sure to look at the underside of tree bark for an S-shaped pattern. This indicates the presence of the Emerald Ash wood-boring beetles, a pest that can quickly kill the tree.

If you notice defoliation of some branches, it may be a sign of anthracnose. Any signs of brown areas on leaves or cankers on the branches should be your call to start pruning back ash trees in the very near future. These pests weaken the tree and can create serious problems if not addressed quickly by trimming back ash trees.

How to Prune Ash Trees

Use a three-step trimming method to remove branches from an ash tree.

  • First, make a cut on the underside of the diseased or damaged branch. This cut should pass a quarter of the way through the branch about half a foot from the branch collar.
  • Next, cut off the branch completely, making the cut one inch past the initial cut. This cut should be made from the top side of the branch.
  • When you finish this cut, the branch will fall away. As a final step, remove the branch stump.

What’s The Best Time to Prune an Ash Tree?

Late October to early March.

Expert insight into the best time to prune an ash tree; the advantages of ash tree pruning, and how to avoid the risk of spreading disease and harming the tree.

The ash tree is native to the UK and is known for its slender, elegant appearance and its desire to grow in groups to form a shady, domed canopy. Ash trees can live to a ripe old age of 400 years and benefit greatly from regular coppicing which encourages their growth and extended lifespan.

An Essex Tree Surgeon you can trust Excellent & friendly service at superb rates

Why prune an ash tree?

Ash tree pruning is important to assist the tree in growing healthily. Only with the correct pruning methods will the ash tree develop a strong growth, and the process will also allow for the circulation of air and sunlight amongst the branches of the trees, which is effective in helping to reduce certain diseases.

The ash tree is, unfortunately, prone to disease, pests and borers which means that special attention is essential. Regular removal of diseased, broken or dead branches will keep the tree at its optimum health and pruning will aid central leader growth which will provide the tree with a strong core. Furthermore, pruning also prevents pests and other elements that can cause decay from infecting the tree as a whole.

Pruning an ash tree or in particular a group of ash trees will have a positive aesthetic effect on the landscape too, not to mention how it makes the tree safer. It is also an investment for the future, as good pruning early on in the tree’s life will result in a lessened need for pruning once the tree is mature.

So, all this considered, when is the best time to prune an ash tree?

When is the best time to prune an ash tree?

Whilst it really depends on the reason for pruning, ash trees are ideally trimmed back during the late dormant season, i.e. late in the winter before the new spring growth starts to appear. The dormant season for a tree runs from late October to early March.

Pruning a tree creates a wound, and these are best left for the shortest amount of time possible before the new growth starts and the healing process can begin.

If however you are seeking to remove broken, dead or diseased branches then this can be done at any time of the year and indeed should be done as soon as any hazardous branches are spotted. It is the removal of live branches for, to example, let light and air circulate, that must wait until winter.

The most common types of tree pruning for the ash tree are crown reduction, crown lifting and crown thinning.

Other Considerations

When you are looking for problem branches in your ash tree, be sure to be on the lookout for an S-shaped pattern. This indicates the presence of the Emerald Ash wood-boring beetle which is very serious as this creature has the ability to kill a tree. Additionally you should be aware of branches that are bare of leaves as this could be a sign of anthracnose. If you spot any brown areas on the leaves or cankers on the branches then you should instigate the pruning process as soon as possible, preferably taking urgent advice from a qualified tree surgeon.

Always be on the lookout for pests and disease.

Tree Preservation Orders

No tree work should be undertaken without first checking for the presence of a Tree Preservation Order (TPO). If there is one, then permission will be required for the works, and this can take up to eight weeks to materialise. Similarly, if the tree is situated in a conservation area, then again permission will be required for any works.

Pruning an ash tree can be dangerous. Ash trees grow to a considerable stature which means experience and expertise in working at height is crucial in order to undertake the task safely.

Using a qualified tree surgeon with the right certifications and adequate insurance is the wisest advice you can follow. They will advise on the most appropriate timing for your ash tree pruning and will also be able to identify any symptoms of disease or decay and then advise you on what action needs to be taken.

The importance of ash tree pruning expertise

No matter what species of tree you are looking to prune, you really should not proceed unless you possess a good understanding of tree biology. Improper pruning can lead to lasting damage and may even shorten the lifespan of the tree. Expert pruning on the other hand can lead to prolonged good tree health and structure and a much enhanced aesthetic appeal.

If you have an ash tree on your land that needs pruning, why not talk to T.H. Tree Services? As fully qualified and highly experienced tree surgeons, we are able to offer extensive knowhow when it comes to ash tree pruning. For a free, no-obligation quotation, give us a call on 01268 642814 or get in touch here.

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May 28, 2018 by Mrs J Easton on Tree Surgeon in Essex | T.H Tree Services | Reviews Fantastic service

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Hi Mrs Easton, thank you for leaving a lovely review. The team are really pleased they come across professional and friendly.

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Don’t Prune Your Ash Trees Until the Fall

Don’t prune your ash trees.

That’s the message to hear as we head into spring.

Even with the late-season cold weather, it’s now warm enough for the insects that kill ash trees, the Minneapolis Park and Recreation Board announced Thursday. Emerald ash borers, which have been found in Minneapolis, are normally active May through Labor Day.

People should stop pruning ash trees until the fall in order to minimize the risk of emerald ash borers. Residents should also avoid moving any part of an ash tree—including firewood and branches—while the beetles are active in order to avoid inadvertently moving them to uncontaminated areas.

Emerald ash borers have killed millions of ash trees in 13 states. About 20 percent of Minneapolis’ tree canopy is made up of ash trees. The Minnesota Department of Agriculture has issued a state quarantine on firewood, ash trees and ash tree products for Hennepin, Ramsey, Houston and Winona counties.

Click here for tips on how to identify whether you have an ash tree in your yard or to visit the Minnesota Department of Agriculture’s emerald ash borer Web page

DEAR NEIL: We have moved into a 50-year-old house that has a mature Arizona ash. It’s too wide for where it is. I’m afraid its branches will break in a storm. When can it be pruned?

Dear Reader: You can prune ash trees at pretty much any season, but winter is best because you can see the limb structure plainly. Don’t leave stubs as you make the cuts. Each cut should be flush with a remaining branch or with the trunk.

Because this is a mature tree, you may want to have a certified arborist do the work for you. I usually say that you shouldn’t cut anything that you can’t reach from the ground.

DEAR NEIL: We have had this bed of cast iron plants for about 10 years that have spread out far beyond where we planted them.When and how can I trim them back closer to the trunk?

Dear Reader: Aspidistras are expensive plants to buy and they’re relatively slow-growing as well. Yours have done really well. These plants have large and heavy root systems that can be dug with several leaves intact and replanted into new beds. If you don’t want the excess plants, find a friend who does. But don’t just cut them back and destroy them. If you have some utility scissors, you can easily trim away the browned tips. Leave a taper to keep them looking natural.

DEAR NEIL: Why would an old oleander not bloom this year for the first time in the 30 years that we have had it?

Dear Reader: That’s hard to know without a lot of additional facts. Many oleanders in Texas were hurt by last winter’s cold. That will cut into the flower production. If you pruned it during the winter, that would have the same effect. It also could be that adjacent trees have finally gotten large enough to shade it excessively. You can’t do much about it now, so just sit tight and see how it does next year.

DEAR NEIL: I cut down two mature crape myrtles that were making a mess over my car. But then sprouts came up everywhere that the crape myrtle roots had been. How can I kill them?

Dear Reader: If you continue to have sprouts emerging, apply a broadleafed weedkiller spray. There are several combination products, but a clue that you have a broadleafed weedkiller is if it contains 2,4-D. You may have to spray several times in the next year, but the sprouts will gradually die away.

DEAR NEIL: We have property that had high water on it in June. Nutria swam up to three bald cypress trees and peeled the bark off their trunks for about a 12-inch swath. The trees still look fine. Is there anything I can put on the exposed trunks or will they heal on their own?

Dear Reader: Pruning sealant would actually slow healing down. You could hire a certified arborist to look at the trees and give you advice. If they’re not browning by now, after all of this hot and dry weather, I would hope that they will pull through. Perhaps the damage wasn’t as deep as you might have imagined.

Email questions for Neil Sperry at [email protected] Questions cannot be answered individually.

Do I need to change the irrigation for my Shamel Ash trees?

This does likely have something to do with watering, but there are several issues here. When watering, it is better to give the water all at one time, ideally over a period of ½ hour, and make sure it soaks in well. Then let it dry for a time before watering again. The time will depend on environmental factors, such as temperature, precipitation, and cloudiness. Making a shallow trench around the trees will keep the water where it should be, and help keep precipitation in place.

Mulch with a layer of organic matter to a depth of between 2 and 4 inches. This will conserve soil moisture, keep the soil temperature more even, and add organic matter as soil microbes work it in. Keep it away from the trunk, though, in a 6″ diameter circle.

Those trees are on the larger end of those that are regularly transplanted. On trees this size, the first 2-3 years are often spent rebuilding the root system, which was severely damaged during transplanting. What you should do is make it as easy as possible for the tree, by watering properly, fertilizing very lightly, or with an organic fertilizer high in phosphorus, mulching, and even cutting back crowded top growth (which is possibly pulling more energy than is well sustainable.

From your picture, the trees look OK. Again, water more, in the style described above, fertilize, and mulch. Also, that wall will be very reflective, so that may have some affect on the leaves drying. If you can cover it with something less reflecting that will be beneficial. In any case, plan on at least a couple years before any major growth above ground.

Arizona Ash Tree Care And Diseases

Arizona Ash trees do very well in the Arizona climate and there are in excess of 65 species in the state. Read on to learn more about how you can care for these msagnificent trees and treat any diseases they may encounter.

Species Of Ash Tree

Here are come of the most common and popular Arizona Ash Trees together with their latin names you cna find in the state of Arizona.

  • Singleleaf ash – Fraxinus anomala
  • Shamel ash – Fraxinus uhdei (aka. ‘tropical ash’)
  • Raywood ash – Fraxinus oxycarpa
  • Littleleaf ash – Fraxinus greggii
  • Green ash – Fraxinus pennsylvanca (aka. ‘water ash’ or ‘swamp ash’)
  • Goodding ash – Fraxinus gooddingii
  • Fragrant ash – Fraxinus cuspidate
  • Fantex ash – Fraxinus velutina (aka. ‘Rio Grande ash’)
  • Chihuahua ash – Fraxinus papillosa
  • Arizona ash – Fraxinus velutina (aka. ‘modesto ash’ or ‘velvet ash’)

Characteristics Of Ash Trees

The ash tree is a deciduous tree, meaning they shed leaves at the end of the growing season with the majority of ash trees drop tehri leaves within about 2 weeks of the end of the growing season. They generally produce seedlings throughout the entire year or once a year in large numbers.

Most ash tree species will quickly grow, resulting in having fast shaded areas. When trees grow quickly, it often results in surface roots. Ash tree roots tend to grow near the surface, making them tolerant to rocky soils and alkaline soils. Basically, you should expect to require trimming ever few years to keep ash tree’s healthy with a good branch structure. If trimming is ignored, it can cause weak growth and breakage. This is bad for multiple tree trunks, because they will eventually fall and could cause damage. Instead, establishing a single central trunk during the tree’s youth is best.

Prior to planting your new ash tree, there are things to consider. First, you want to ensure your yard is large enough to contain it, because ash trees grow quick, and large. The majority of ash trees mature at 40ft to 50ft, but there are species that get over 80ft high, and they all have round, full canopy’s.


Like various plants, the Arizona ash tree is open to diseases that include, cankering, fungal infections of differing kinds and mildew as well as rust diseases, webworms, leaf scorch, crpenter worms, mites and borers, not to mention verticillium wilt, a soil born fungus. Trees that are planted and still growing that endure a poor environmental condition have a higher vulnerability to problems like these, making it significant to ensure fertilizing and watering are done adequately to keep the tree’s defense up.

Maintenance Of Ash Trees

Well kep ash trees provide an outstanding addition to your Arizona landscape. However, if you allow your ash trees that are not taken care can end up being an eyesore. There are ash tree species which have a slight drought resistance, but the majority of ash tree varieties will require plenty of water. To create the best setting for ash trees, flood irrigation should in installed. At the very least a garden hose should be used for a deep soak one or two times a month. In addition, you may desire fertilizing the ash tree often. There are two benefits to mulching your ash trees. First, it enriches the soil as organic matter is broken down. Second, the mulch retains moisture from the watering to maintain wet soil for longer periods. Although ash trees are not particularly simple to care for, having a healthy ash tree is worth the effort. When well cared for an Arizona ash tree provides great shade, and they are sure to improve your landscape.

If you own a property in the Phoenix Valley our team of trained, licensed, and insured tree cutting professionals will cut down and remove your tree safely and affordable. Every one of our skilled technicians understands our safe tree removal and cutting protocols and work together to get the job done quickly and safely. Keeping your property in the best condition possible while removing the tree is also our top priority. We remove the tree, clean up the mess, and leave your property in great condition.


Fraxinus spp.

Anthracnose (fungus – Gloeosporium sp.): Large areas of the leaf, especially along the edges and veins, turn brown. Premature defoliation will follow severe anthracnose infection during wet seasons. The disease may be confused with problems caused by weather adversities or other physiological problems. Spraying with a fungicide two or three times at 14 day intervals during humid periods will control the disease.

Leaf Spots (fungi – Cylindrosporium sp., Marssonina sp.): Among the most common foliage diseases of ash that occur virtually wherever ash is grown. Lesions appear early, hundreds may develop on a single leaflet. They are very small at first. Spray as recommended for anthracnose to control the disease.
(fungi – Mycosphaerella fraxinicola, Phyllosticta sp.): Another common leaf spot of ash appears toward the end of summer. Groups of small dark fruiting structures form in spots on the bottom of the leaf, while the upper side may show only a slight spotty discoloration. By the time the spots on the top turn brown, defoliation has begun. Spray as recommended for anthracnose to control the disease.
(fungi – Cercospora fraxinites): Spots are irregular to almost circular, three to seven mm in width. The long, thin, many-celled spores are produced on black stromata within the dull gray-brown spots. Spray as recommended for anthracnose.

Rust (fungus – Puccinia sparganioides): Swollen and distorted gall-like structures occur on leaves and twigs. The orange swellings are more common early in the growing season, particularly in the Gulf Coast area. Two stages of the rust fungus are known: one which occurs on ash trees, the other on grasses, Spartina sp. Spraying with fungicides at two to three week intervals during early spring will control the disease.

Cotton Root Rot (fungus – Phymatotrichum omnivorum): Ash is moderately susceptible to the cotton root rot fungus, particularly during the younger stages of growth. (See section on Cotton Root Rot)

Wood Rots (fungi – Poria sp., Fomes sp., Polyporus sp., etc.): Most of these fungi attack only weakened or wounded trees. Infection usually takes place through wounds caused by lawn mowers, pruning, or strong winds. Trees decline slowly for no apparent reason and the fungus slowly rots the wood. After the disease has progressed for some time, leathery, hard structures (conks) can be seen attached to the lower parts of the trunk. These are fruiting bodies of the fungus appearing as bracket growth during certain times of the year. Control is accomplished by avoiding mechanical wounds, treating exposed wounds with pruning paint, fertilizing trees as needed and protecting from insects.

Powdery Mildew (fungus – Phyllactinia guttata): White powdery fungus growth on the leaves during the summer, then forming small black round fruiting structures in the late summer and fall. Damage is usually not extensive enough to warrant control.

Hairy Root (bacterium – Agrobacterium rhizogenes): A large number of very small roots develop either from the base of the stem or the larger roots. No control is known.

Cankers (fungi – Cytospora sp., Diplodia sp., Dothiorella sp., Nectria sp.): Several fungi cause branch and trunk cankers on ash. None of them are very common. Prune out infected branches. Maintain the trees in good condition by fertilizing, watering and spraying for insects.

Nematodes (Root Knot, Dagger, etc.): (See section on Root Knot Nematodes and Other Nematodes)

Leaf Scorch (physiological): (See section on Leaf Scorch)

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