I am new to this great website and posted my question on the garden forum w/no responses as of yet...I'm still learning the system! Anyway, I'm in zone 4, and my 5-year old redbud is sick....last spring it didn't bloom toward the end of april as it normally does and when it finally did get some blossoms (late May) they were very sparse. When the leaves came out, they were approx. 1/2 the normal size. In addition, it looks as if there is a ring on the ground, the diameter of the tree (roots), approx. 10', as if fertilizer had been spread in a circle, although it hadn't. The tree is located within 5' of a large old maple, has 2 dwarf apples within 8' of it, and other very large old maples within 15'. This has always been a beautiful tree and I am desperate to know what to do for it. Any suggestions? Thanks, and boy am I going to love this site!!
Sick Red Bud tree
Quote from Dirr's book :
" Canker is the most destructive disease of the Redbud and can cause many stems to die . Leaf spot and Verticillium wilt are other disease problems . Tree hoppers , caterpillars , scales , and leaf hoppers can also cause damage . .
Xylaria polymorpha root rot may play a role in the decline of urban trees . "
Stress is the Redbud's greatest enemy and can cause the forementioned conditions to occur .
Your local agricultural agent should have a direct link to the plant pathology department at Cornell if they can't diagnose your problem themselves. Take them a sample of the soil, some of that "ring" you are describing, a few of the surface roots in the area,a few of the affected twigs, some of the normal one, and if there's any open wounds, or obvious canker spots, a sample of that as well. It's probably too early for leaves in your area, but the ag agent might want a sample of them when they leaf out too. Your tax dollars have already paid for this service, so use it! :*)
Lots of times, redbuds have an injured trunk when they are young, and that spot develops canker as the tree grows older. Not much you can do, other than try to limit damage to the bark from string trimmers, etc. and treating any open wounds with a fungicide until they've healed, but those are preventative measures. Usually, unless the canker is confined to just one of the upper branches that you can remove, and a substantial portion of healthy tree remains, the plant slowly declines and dies and you are waiting on the inevitible. Most understory trees like redbuds or dogwoods are not very long lived when compared with the oaks and maples that give them their shade.