A recent windstorm knocked over our beautiful willow tree. (it'd been poorly pruned and had several, weak trunks.)

1.How fast will a weeping willow tree regrow from the stump?

2. Would the tree be stronger if we just replanted one?

3. We still have a huge stump and a sprout that came out of it--if we cut the stump to the ground, will a willow sprout from it?

Willows will sprout from a twig. They are very hardy and want to live. I would cut the stump to about 8" and watch for regrowth. In the mean time, take the sprout and put it in a pot. Keep it well watered and you will have a back tree in no time.

You will have a sturdier, healthier tree if you plant a new one, and it will be larger than the twig you have left, sooner. It will also look better than seeing the stump left over from the old one. If you don't completely remove the old stump, you will always have to look at it, the new tree will not fill-out the old stump. That part is dead. What is left of the old tree will fight to come back from the roots of the old tree, so if you have a sentimental attachment to the old tree, encourage the new start, and help it survive by removing the old stump and other old roots.

Trivia: industry studies show a 5-gallon tree from the nursery, and a one-gallon tree will be equal in size in 15 years. A start from the old tree will take about 1 year longer.

Willows grow pretty fast.Providing the stump is strong without cracks or splits, you should be ok. What you can do is wait until a sapling sprouts, then cut off sapling, cover with rooting compound, and plant alongside stump.The saplings take very easily.Our willows here in NZ are used as wind breaks, and grow tall within a year or two. Good Luck!