Cutting down an ash tree does not always kill it. If the roots are still alive, the stump can push up new shoots. In one question to the Toronto Master Gardeners, a sapling several feet tall was growing from the stump of an ash that had died a couple of years earlier. Whether you should let that happen, and how to stop it if not, depends mostly on why the tree came down.

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The short answer: yes, an ash stump can grow back. The Toronto Master Gardeners explain that a sprout from a stump means the root system is still viable. Sprouts from a stump may not develop into a strong tree, and if the ash died from emerald ash borer (EAB), the new growth is vulnerable to the same pest. To stop regrowth, cut sprouts and the stump low, or treat a freshly cut stump with a herbicide labeled for stumps, as UF IFAS describes: right after cutting, wetting the living outer ring of the stump.

Why ash stumps sprout

UF IFAS notes that simply cutting woody plants often leaves live stumps and roots that resprout. The Toronto Master Gardeners describe a shoot growing from an ash stump as a stump sprout: the root system is still alive and sending energy upward into a new shoot.

Stressed but living ash trees do something similar. An Ask Extension expert in Michigan explains that stressed trees may grow new branches and leaves wherever they still can, so stressed ash may show new growth at the base of the trunk or on main branches. The Morton Arboretum notes that in later stages of emerald ash borer decline, suckers called epicormic shoots may form low on the trunk.

Should you let an ash stump sprout grow?

Usually not. The Toronto Master Gardeners give several reasons:

Weak structure. Sprouts growing directly from a stump may not develop a strong enough foundation to become a large tree, and may not withstand heavy snow or wind.
Questionable wood strength. It is not clear the new tree’s wood would be as strong as the original’s.
Ash is not suited to coppicing. Regrowing stems from a stump (coppicing) is an old practice for some species, but ash is not one of the recommended ones.
Emerald ash borer. If EAB killed the tree, new growth is especially vulnerable to being infested again.

On that last point, the Ask Extension answer is clear that sprouting does not mean the stump has developed resistance to EAB. The Morton Arboretum explains that EAB attacks healthy trees as well as stressed ones, and that infested trees may die within two to four years.

How to stop an ash stump from growing back

Option 1: cut low and remove sprouts

The Toronto Master Gardeners suggest cutting the old stump closer to the ground and removing the sprout with it. Where EAB is a concern, they advise bagging the removed material and putting it out with the trash, to avoid spreading insects. Expect to repeat sprout removal if the roots keep pushing up shoots.

Option 2: treat a fresh cut with herbicide

UF IFAS Extension describes the cut-stump method, used after cutting a tree to eliminate or greatly reduce resprouts from the stump or lateral roots:

Cut the stump and brush off the sawdust.
Apply herbicide to the cut surface as quickly as possible. If applied right away, a herbicide and water solution is enough.
If the cut surface has started to dry, use a herbicide and basal oil product instead, applied to the top and around the collar of the stump, or recut the stump and treat the fresh surface.
On stumps over 3 inches across, wet the outer edge thoroughly, because that ring is the only living tissue. On smaller stems, cover the whole cut surface.
Add a tracer dye so you can see which stumps you have treated.

UF lists products such as triclopyr, glyphosate and imazapyr for cut stumps. It notes glyphosate only works when applied immediately after cutting, and that imazapyr is highly active in the soil, which matters near plants you want to keep. Always read the label and use only a product labeled for cut-stump treatment.

Option 3: grind the stump

Having the stump ground out by a tree service removes the stump itself. Watch the area afterward and cut any new sprouts at their base.

What about the wood?

The Morton Arboretum advises against moving firewood, which can carry EAB larvae. Keep ash wood local, or follow your area’s rules on disposal.

Planting after an ash

Ash was once widely planted. The Morton Arboretum describes green ash as a fast-growing tree with weak wood and branch structure, and the Toronto Master Gardeners note that growing new ash trees is not recommended in Toronto because of EAB. When you replant, choose a different species suited to the site; the easiest oaks to grow are one long-lived option.

Sources

Ash Tree: Cut stump but remove sucker?, Toronto Master Gardeners
Ash Tree regrowth (Michigan, expert response), Ask Extension
Emerald Ash Borer, The Morton Arboretum
Herbicide Application Techniques for Woody Plant Control (SS-AGR-260/AG245), University of Florida IFAS Extension
Green Ash, The Morton Arboretum

Top photo: Ryan Hodnett, CC BY-SA 4.0, via Wikimedia Commons

Will an Ash Tree Stump Grow Back?