Locust Tree – All Branches Dead

(Question)

015Hello – I planted 4 locust trees at my cottage 4 years ago. Last spring, one of the trees appeared dead (no leaves) in the established branches but had vigorous suckers growing from the trunk all of the way up to the first branches. I removed the suckers and left the tree in place. The same thing happened this spring. The other 3 trees are doing fine.

The location is a filled wet area. The trees were from a nursery and were planted with a large root ball and lots of additional good quality added soil. The planting hole was about 1 yard square wide and deep. The trees were about 8 feet when planted. All trees get lots of, sun for about 1/2 of the day. They were watered well through their first year and occasionally thereafter in very dry periods. The surface of the area is dry – because of the history of the location I believe that there is lots of moisture below. There are no structures or other trees nearby.

The location is in growing zone 4a.

Is there any hope for this tree?
If not, how can I avoid the same result in the same planting location with another tree – this species or other.

Thank You

(Answer)

Thank you for contacting Toronto Master Gardeners.

It is so heartbreaking to lose a tree. Locusts Gleditsia triacanthos is a very resilient tree but unfortunately in this case it has not worked out. Your description of the location and picture do not point to any local issues that may have killed your tree.

The issue with the tree may have begun the day it was planted. I can not quite see in the picture but from your description of the hole you dug you may have planted the tree too deep.

Trees should never be put in a hole that is deeper than their root balls. When you look at the trunk of a tree you can see where the bottom of the trunk flares and where the roots begin. When placed in the hole the flare of the trunk where the roots begin should be flush with the ground or even a bit higher if you suspect the ground will settle under the tree. Having dirt packed up tight to the trunk causes the trunk to break down and destroys the cambium layer underneath. When this happens the tree is girdled and the tree eventually dies.

If you replace this tree make sure the root flare is not buried. It is also recommended that the back fill not be amended with higher quality soil or any fertilizers as this encourages roots to stay local and not grow outwards looking for nutrients and water. It is best to use the local soil which is the same as the surrounding soil.

Once planted the watering of the tree is important. it needs to be watered slowly over a period of time so the water filters down to the roots. If you put a generous ring of mulch around the trunk ( in a doughnut shape – ensure the mulch is not up against the trunk) will help the soil to maintain the moisture longer and discourage weeds that may compete with the tree for water and nutrients.

I am including a link with further information for you.

Good Luck.

http://www.treesaregood.com/treecare/resources/new_treeplanting.pdf