Question
QUESTION: I have a willow on the side of a small pond. I estimate that the tree is at least 20 years old. From 2004 thru 2007 I had a horrible invasive water plant take over the surface of the pond. No amount of non-chemical treatments even made a dent in the growth of the azolla (plus another type of invasive species.) So I very reluctantly resorted to having a marine biologist chemically treat the pond. I was most concerned about the willow, as many roots are visible in the water. He said it wouldn't hurt the tree (or my koi).
That was last spring/summer. While the water is clear, my poor willow is at least two-thirds bare, especially the bottom limbs. I put fertilizer spikes in recently, but I don't know if that will help. What can I do/expect concerning the improvement of this tree. Will it likely die? Could it rebound in another year, potentially? I know you can't definitively answer this without seeing the tree, but I'm desperate for some guidelines. This tree is truly a member of my family!
Thanks!

ANSWER: Without knowing what herbicide was use it will be hard to determine if this is what cause the damage to the willow. BUT whatever it was would do its damage the first couple of weeks following the application so if the tree is still alive it will make it. As long as the top is still alive (has foliage ) it will continue to grow. This next spring I would cut all the dead branches off and it may sprout back new ones from the main trunk. Willows do sprout well. I am not a fan of fertilizer spikes for tree (they seem to concentrate the fertilizer and burn the roots close to the spike) instead I would recommend 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree (not in the water) and watered in good. I would do this now just before a good rain and again in the spring. This will promote root and foliage growth. Without seeing the tree is is about the best I can do.

---------- FOLLOW-UP ----------

QUESTION: My rating expresses both my gratitude to you and the reasons I may have trouble following your advice 100%. So, I continue with this brief follow-up question:  if the branches are not sprouting now, does that mean they never will again? There are so many huge limbs that are bare, and so many, many smaller ones very high up in the tree. I don't know how I could possibly prune those.
Thanks.

Answer
The branches may still be alive but have not put on new leaves yet but they may also be dead. I would wait until next spring to prune off any dead branches this will give the tree time to bud out next spring and you can tell which ones are dead or alive easily. It is not necessary to prune them off --if you can not reach them  they will drop off by themselves overtime. If you do prune them, cut them back to the trunk. The small ones will drop off by themselves.