Many years ago the ice storm of 1998 messed up my poor willow tree. There have been several small ice storms since then and it has never recovered. I do not want to get rid of it because it is part of my late grandmothers tree so it is special to me. it looks horrible and I am wondering if I can cut it back to nothing but a stump and how high should it be.
If you cut it down to a stump, it will grow a lot of branches and end up looking like a bush, not a tree.
If you want to have something that looks like a tree, cut off one branch that will be the new trunk, stand it upright in a bucket of water (outdoors) until it starts to grow roots, and then plant it as a new tree.
It may take a few weeks for the roots to appear (keep the bucket filled with water, of course) but willow is unique, in that any piece of a willow tree will produce roots if it has enough water, so you don't need to follow any special procedures to take a cutting.
After you plant the cutting, give it lots of water every day until it is growing strongly.("Lots of water" as in a few buckets full of water poured on the soil, not a spray on the leaves). Unlike some plants, it is impossible to kill a willow with too much water.
Willows are not naturally long-lived trees, and if your specimen has been damaged and looking unhealthy for the past twenty years then there may not be much hope for restoring it to its previous health.
But there are three possible ways to continue its life, in different ways:
- Take a cutting, as recommended by alephzero; this has a very good chance of growing into a new well-formed tree. It will be a clone of your current one, and should outlive you.
- Take a seed (if your current tree is still capable) and grow a new sapling; you may get a new well-formed tree, which is a descendant of your current one, and should outlive you.
- Coppice it by cutting it all right down to the base, and letting it regrow from the roots. Assuming it still has enough life in it to regrow at all, it will come back in a very different shape (multiple thin stems, instead of one main trunk), but it will be the same specimen still alive and still growing. In terms of lifetime: careful repeated coppicing and some good luck can keep a tree alive forever.
None of these will be exactly the same tree as it was in its youth, but each one will be a continuation of it in some way.