My Redbud Tree Sapling
Hi: This past March, I planted a lovely Red Bud sapping (I would say approximately 3 years old or so) in my front yard on Capitol Hill in DC. I had recently taken out a dogwood tree stump from a dying dogwood three years ago and planted it there. Anyway, a farmer from Southern Maryland put the Redbud in, who seemed to know what he was doing. It bloomed nicely in April and it sprouted some new green leaves. Everything seemed great. Then after the intense rain we had two weeks ago, I woke up one morning to dead leaves. It wasn't gradual at all. Literally in maybe one or two days, ALL the little green leaves were brown and curled. The little branches are still supple, so I don't know if it's dead, dying or will come back. I seems too sudden for a disease... Any thoughts? Not sure how good these pictures are, but hope they help.
District of Columbia County District of Columbia
A disease or insect would not impact your tree this quickly. This suggests an environmental/cultural problem.
If you have a mostly clayish soil, and the planting hole was backfilled with a lot of organic amendments--not just the original clay soil--then the problem may be something called a "bathtub effect."
Clay soil absorbs water slowly and drains very slowly. This is fine if all the clay in an area is the same clay soil. But if a hole is filled with highly organic soil, which quickly fills with water, and the surrounding clay soil won't let it drain quickly, then the plant sits in soggy soil for so long it can drown the plant's roots. (Plant roots need oxygen.) This might not be a problem with average rainfall, but we've had torrential rains and your tree may have been "sitting in water" too much.
You can scratch the bark and look for healthy green tissue to determine if the tree is dead. If it is still alive, and you suspect that the problem is excess water, you can dig up the tree (when soil is not saturated), and either amend the entire area it is in with organic matter to make the soil all the same, or replant it and use the native soil to backfill.
We also cannot see the tree's flare in the photos. A tree's trunk should not go into the soil like a lollipop. The tree's flare (when it widens at the base) should be visible and above ground. The tree may have been planted too deeply, we can't say for sure because of the mulch. Mulch should never touch the base. Keep it back a few inches. Also, keep it no deeper than 2-3 inches.