Japanese Weeping Willows pruning

[power270lb]

Willows are quite cold hardy. Later in Spring, put them outside for the summer. Do not bring them indoors for the winter. Simply set their pots on the ground, they should be fine for the winter outdoors in NJ. Don't put them outside now, it takes a couple months for a tree to adapt to cold, but once outside for the summer, just leave them out for the autumn and winter.

I had a black willow for a few years. It survived -17 F, roughly -27 C, simply set on the ground for the winter. The weeping willow and other willows are similarly hardy. Don't baby them over the winter. You will have more trouble with trees kept too warm than trees allowed to get cold.

That's what I plan to do. You didn't build a cold frame for the roots? What about pruning? They're getting so long now it's hard to fit in my setup (above comment) I hear they're prone to dieback. Only goal is thicker trunks with more branches and ramification.

 

[Leo in N E Illinois]

That's what I plan to do. You didn't build a cold frame for the roots? What about pruning? They're getting so long now it's hard to fit in my setup (above comment) I hear they're prone to dieback. Only goal is thicker trunks with more branches and ramification.

No cold frame for the roots. The pot, being set on the ground, does get some heat from the earth. There is loose autumn leaf litter up to roughly the pot rim. Then we usually get snow before our deep freezes. An inch or two of snow over the leaf mulch probably keeps the roots 5 to 10 degrees F warmer than the cold air temp. Point is, no fancy cold frames, no out of the ordinary care. They survive in the wild near me, no reason they shouldn't survive in my back yard without cold frames.

 

[power270lb]

No cold frame for the roots. The pot, being set on the ground, does get some heat from the earth. There is loose autumn leaf litter up to roughly the pot rim. Then we usually get snow before our deep freezes. An inch or two of snow over the leaf mulch probably keeps the roots 5 to 10 degrees F warmer than the cold air temp. Point is, no fancy cold frames, no out of the ordinary care. They survive in the wild near me, no reason they shouldn't survive in my back yard without cold frames.

Question in regards to pruning, ramifications, thicker trunk. What's your experience/advice for each?

 

[Leo in N E Illinois]

Don't prune while dormant, die back is more likely then. I really have not figured out how to avoid die back entirely.

Thicker trunk - let it grow without pruning. To get a nice thick trunk you may have to let it get 5 feet tall or taller before cutting back. It is the total surface area of the leaves that a trunk supports that does the thickening of the trunk. Usually letting a leader grow tall will also give the result of more leaves, and more leaf surface area. Which will drive the thickening of the trunk. But an alternate approach is to prune to cause many branches, which will carry many leaves. This does mean more but likely smaller scars to heal once you reduce the tree back down to bonsai size.

Most bonsai go through a phase in early development where they are 5 to 10 times the size that they will be as a finished tree. We don't grow trees up to become bonsai, we take larger trees and bring them down in size to become bonsai. If you start small, you have to let them get big for a while, so that you can bring them back down to size.

Ramification, no special tricks. It will come with time.