I have 3 ornamental cherry trees (the type that grow in Washington, D.C.). They have been planted in our yard approximately 5 months and are doing beautifully. They have rubber mulch around them. Recently, leaves here and there become yellow to red and I remove them. I noticed then there were little black ants crawling up and down the branches. I pulled back the rubber mulch, and there were active ant-like insects crawling through the dirt. As the feeder roots to the cherry tree come to the surface, I don't want to treat the dirt, unless I have to. I did; however, spray a mixture of Neem Oil on the trees' leaves, both sides. The trees do not touch each other, but all 3 are suffering the same dilemma. What do I do or don't do? Thanks!
Ants on cherry trees are usually tending aphids for their honeydew; so check for aphids on the underside of leaves. There are many sprays available to temporarily eliminate the aphids, but the best long term treatment is to apply a band of Tree Tanglefoot on the trunk of each tree to keep ants off.
I'd also remove the rubber mulch. http://puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/rubber-mulch.pdf If these trees are not adapted to your part of Florida you are going to have an uphill battle. In the past there have been many posts on the internet from people struggling with Japanese flowering cherry trees under eastern US conditions.
Definitely remove the mulch. Even non-toxic organic mulches, like a thick layer of straw, grass clippings, wood chips, whatever, are deleterious to the normal development of the tree root system, causing shallow, week roots, that are not adequate to support a healthy, disease resistant tree in the long run. Rubber mulch, additionally, contains ingredients that are toxic to the soil ecosystem. No healthy, disease resistant plants can be grown successfully in unhealthy soil.
Even non-toxic organic mulches, like a thick layer of straw, grass clippings, wood chips, whatever, are deleterious to the normal development of the tree root system, causing shallow, week roots, that are not adequate to support a healthy, disease resistant tree in the long run. How do you figure? Shallow roots are normal, what do think happens in nature where trees are growing under forest litter? In humid situations like that roots may even come out of the litter and then plunge back in, like dolphins (albeit a lot more slowly!) without deleterious effect.
