The question is, "Why is the top of this tree dead???"
When I am diagnosing a plant problem I try to go through a process of elimination. I try to eliminate all of the 'usual suspects', the very common issues that cause plant health problems. Whatever is left, must be killing the tree.
In the case of this redbud, I do not see cracked and swollen bark which would indicate fungal canker. I do not see the tell tale signs of ambrosia beetles which would be pencil point sized holes with sawdust protruding. I do not see the quarter-sized vole holes in the soil at the base of the plant which would indicate these little rodents are munching away on the roots.
The tree was buried way too deep in mulch. Volcano mulching can be bad for plants long term. Burying plants too deeply at planting can smother roots and lead to girdling roots. Excavating the root collar, the swollen area where the trunk meets the roots, can extend plant life. In this case, although the plant had way too mulch, I think the planting is too recent to have cause many problems.So what could be causing this tree to die? This tree is a grafted tree meaning the 'Rising Sun' Redbud TM was grafted onto a straight species root stock. The swollen area at the base of the tree where the two parts were joined is called the graft union. Sometimes this juncture fails for whatever reason.
