White Ash Tree Profile

white ash tree

The Spruce / Autumn Wood 

For years the White Ash was a shade tree staple in much of North America. Fraxinus americana is large stately tree with a round growing habit, that grows
50 to 80 feet tall at a rate of one to two feet a year, it is an important part of the
landscape of this country. If you've heard a baseball being hit off a bat, or
seen one of the many trees that paint autumn colors you've been touched by the
White Ash. You'd be able to find the tree dotting the continent along city streets, in back yards, and along wooded highways from the Midwest to the east coast. Those days feared to be to be passing since the introduction of the Emerald Ash Borer beetle in 2002, a nasty pest that has ravaged the genus Fraxinus across much of the temperate United State and Canada. The good news is that if you know the
warning signs, take precautions, and catch it early you can save your Ash.

Botanical Name Fraxinus americana
Common Name White Ash 
Plant Type Tree
Mature Size 50-80 Feet
Sun Exposure Full sun
Soil Type moist, well-drained
Soil pH Adaptable 
Bloom Time April to May
Flower Color Purplish
Hardiness Zones 4 to 9
Native Area  Eastern North America
closeup of white mountain ash foliage
The Spruce / Autumn Wood 
white mountain ash foliage
The Spruce / Autumn Wood  
white mountain ash tree
The Spruce / Autumn Wood  

How to Grow A White Ash

Finding a White Ash in the nursery trade is getting more difficult in recent years because of EAB. They really are beautiful trees though, and if you put in the work and effort you can grow one from a sapling that will last decades or, if you have one on your property like I do, and you want to save it, hope isn't lost. What you are going to be doing is inspecting your tree more than you ever thought you would and doing some pesticide application when, not if, your tree gets infested with Emerald Ash Borers.

Pruning

If you have a White Ash on your property, either young or old, you are going to want to keep it well pruned. Before you start be sure you have good sharp tools, you should have at least having a pair of pruners, bypass lopers, and a pruning saw for larger branches and always make sure to sterilize your pruning tools before starting to prune with 70 percent alcohol. In the case of a young tree you'll need to train it to have a single leader, or main trunk, this is especially important for Ash trees because of their opposing branch structure. Start this process two to three years after planting. Remember developmental pruning is an on-going process that needs to happen yearly. The best time to do any pruning is mid to late winter when the tree is dormant and has the best chance to heal in the spring with new growth.

When caring for an older tree you'll want to prune to improve tree structure and
help prevent failure in the future prolonging lifespan. All diseased, broken
and dead branches should be removed so they don't spread any issues to healthy
parts of the tree. The most important thing to remember with Ash tree waste,
always check if you are under quarantine before you dispose of anything you
prune. You can call your local DEP or extension agency for clarification.

Dealing With the Emerald Ash Borer

There are signs you need to look for on your tree that are going to alert you if your tree is infested. The first symptom is usually dead branches at the crown. This is why regular professional pruning is so important if you have a White Ash, often these dead branches are out of view from the ground. Second, you might notice sprouts that come out random from hidden buds on the tree. These sprouts are a sign the tree is making an effort to produce extra leaves to help in photosynthesis. The next is the leaf itself, you might notice notch shape indents eaten into its edge. The two telltale symptoms that most people know. Look for D-shaped holes in your tree. These holes are exit holes. There are many insects that make round holes but the EAB is the only one that makes these D Holes. Finally, if you see S shaped patterns in your tree these are called galleries, and are created by the larvae of the beetle as they eat through the tree. If you see any of these symptoms you need to consider either treating it yourself or bring in a professional arborist.

S shaped grooves in a White Ash called Galleries caused by Emerald Ash Borer damage.
EAB damage rnkr / Getty Images

If you decide to treat your Ash yourself with pesticides there are two main ways to approach it. A liquid method or granular method of applying the pesticide imidacloprid. If you have mulch around the bottom of your tree you will need to remove this back to a distance of two feet. If your tree is 12 inches in diameter or smaller at the base you should use a granular treatment. Spread granules evenly on the soil around the base of the plant within 18 inches of the trunk. Wet the soil with enough water to dissolve granules to into root zone. If your tree is over 12 inches in diameter you should use a liquid treatment. Once treated, replace any mulch over the treated area after the mixture has been absorbed into the soil.

Warning

Always read and carefully follow all precautions and directions provided on the container label. Store all chemicals in the original labeled containers away from food, and out of the reach of children, and animals!

For trees larger than 20 inches in diameter or when you're in doubt, enlist the
services of a licensed pesticide applicator or certified arborist in your area.

Common Issues Besides the EAB

The EAB can't take all the blame for the White Ash tree's problems. Even before 2002 the tree was known for having multiple issues that plagued homeowners, arborists, and foresters alike.

Anthracnose is a fungal disease that leaves brown spots on leaves and is often confused with frost damage. It leads to twig deaf and leaf loss and eventual dieback. To treat this try a copper based fungicide or a bordeaux mixture .

A far more serious disease affecting the White Ash is a disease called Ash Yellows which is caused by a virus that damages the trees vascular system. Experts believe the cause of the virus is insects but do not know much more than that. The symptoms to look for are slow twig growth and rapid die back. There is no cure for Ash Yellows and as Ash wood becomes brittle it's recommended for safety reasons to remove the tree as soon as Ash Yellows has been diagnosed.