Accolade Elm: Leaf Damage

Asked July 24, 2019, 1:56 PM EDT

I planted two 2.5" Accolade Elm trees in the right of way (between sidewalk and street) at my home in SW Denver in May of this year. I have been watering regularly. The damage to the leaves started within the last month. Can you assist me in determining what the problem is and if I should treat the tree?

Denver County Colorado

6 Responses

There are several insects that commonly produce damage to Elm leaves however the resulting damage doesn't look like the damage in your photos. For example, Elm Leaf Beetles produce a "lacy" appearance where the interveinal tissue has been eaten but the veins remain (ie. "skeletonizing") and the Elm Leafminer tunnels around between the leaf surfaces.

Have you had hail in your neighborhood? If yes, that may have produced some of the brown gashes and tears. The other possibility is some kind of leaf feeding caterpillar. Caterpillar defoliation is mostly cosmetic on an otherwise healthy tree. I do see good buds forming on your tree and although the growth increments are short, that is to be expected in the first year of transplantation.

If you want a more definitive diagnosis, I recommend you bring a sample into the Denver Extension at 888 E. Iliff Ave. (call first: 720-913-5270) or for the most thorough examination of your tree, have a certified arborist do an on-site evaluation.

Thank you for your response, it is very much appreciated.

I did have hail damage shortly after the trees were planted. They held up pretty well compared to other trees, but they did lose leaves and sustain damage. I will just keep watering them regularly and I am sure next year will a better year for these trees.

Do you recommend using a "plant food" on a regular basis?

Thanks, again!

No, a tree shouldn't need supplemental fertilizer particularly if it's grown with its roots extending into a fertilized lawn area.

Thank you for the message. The trees are actually in the right of way between the sidewalk and road. It is just dirt and rock there. It is just the root ball getting water for now. I am sure the roots will someday extend under the sidewalk and under the grass, but for now and I am guessing next year or two, the roots will be confined to under the rocks/sidewalk. In this case, should I give the tress supplemental fertilizer?

Not a great place for a tree, but sure makes the neighborhood look nicer!

The best thing you can do for a tree is provide consistent moisture, particularly when temperatures hover in the mid-90's day after day.

If the tree is planted in the parkway in dirt and rock, exposed to reflected heat from the street and the sidewalk, and subject to car pollution, I most definitely recommend against fertilizer and stress the importance of providing adequate water - at the rootball, of course, but also in the surrounding area.

Remember: roots grow where there is water - if the rootball is wet but the surrounding area is dry and rocky, roots will opt to grow in the wet area and not grow in the inhospitable area. That will make your tree vulnerable to all sorts of problems and, ultimately, possibly girdle it (ie. kill it).

Thank you very much for your guidance and feedback. That helps me to understand much better how to care for my trees. I will change the way I have been watering the trees.