will my catalpa recover?
I have a 9' tall, 2" caliper, catalpa that was planted a couple years ago. Last year it seemed fine and produced leaves and blossoms. This year it only produced leaves on new shoots from the trunk in the bottom half of the tree. I can't tell by scraping the bark if the trunk wood is healthy in the top part; it is very hard. It is planted next to a 15 yr old corkscrew willow that is in decline. We hoped this would fill the spot. I have given it a reasonable amount of root watering through the year.
Is it possible that the top part of the trunk will not recover but it will still live with an odd shape of branching in the lower 4 ft?
Larimer County Colorado
Yes, it can live, but you have to consider that the tree will never look "normal". If the central leader has died, there is no structure for the tree and it will always look bushy and not tree-like. Plus, the growth that is currently on the tree may be weak and unstructurally sound, which can lead to other issues, like insects, disease and storm damage.
You would be better off replanting a new tree. It could have succumbed to drought or winter dieback. Many catalpas suffered during the winter of 2011-2012...they seemed to have delayed hardiness. This may have also been the case last winter.
Fall is a good time to plant trees, as long as you can provide adequate water during the fall/winter months. And early spring. Here's information on proper tree planting: http://cmg.colostate.edu/gardennotes/636.pdf
The other option is to let it go through another winter and see how it looks in spring. But it's probably in your best interest to consider replanting.
Thank you for the thorough and quick response!
A followup question for you. Is there a problem with planting a new tree near an older, failing tree (with the hope of preserving the shade in that location)? Specifically I am hoping to do this near the corkscrew willow and some elms. The older trees do not appear to be particularly diseased (not that I'd know). In the case of the willow it seems it just is short-lived or can't get enough water. In the case of the elms they seem to have some fungus in the trunk.
This is often done, actually. If you've been to the CSU Oval, you may notice that there are smaller American elms planted to eventually "replace" the older trees as they decline. You just want to ensure that you plant far enough away from the other species and not shade the young trees from the mature tree's canopy. Also, because there is a lot of competition for water in that area from the multiple root systems, pay special attention to the water needs of the plant.
Willows are notoriously short lived species. They are quick growing and have weak wood. They also tend to get various disease and insect issues in our climate. Willows might live perhaps 20 years...(just an estimate).
The fungus on your elms is likely sooty mold, which is caused from honey dew from sap-sucking insects, like scale or aphids. While it's technically a fungus, it's not harmful to the tree and is caused from the insects: http://ohioline.osu.edu/hyg-fact/3000/3046.html