Are they in leaf yet? What cultivar? do they want full sun?

Al

Hi Al. You've provided good advice in the past, so it's great to get your input.
While over half of the Japanese maples I purchased last fall went into the ground, I kept five in their original containers: 'Katsura', 'Shaina', Sharp's Pygmy', 'Shishigashira' and a green laceleaf that falls into the catch-all Viridis group. All but the latter fall into the palmatum category; it's my understanding that these larger and not-so-delicate leaves are less susceptible to scorching by the heat/sun. It seems (from what little I've read ) that these cultivars, like most Japanese maples, appreciate some partial shade in the afternoon; at the same time, many won't reach their full color without full sun. Seems there's a bit of a trade-off: if you can live with some scorched leaf edges periodically, you get the brilliant and excellent coloring .
None of them (in containers and in the ground) are in leaf.

BTW, you suggested last fall that I root prune these containerized maples at or just before "bud break". I really hate to display my lack of understanding, but would you explain that term? Is there a way to estimate when it will occur?
Thanks for sharing your knowledge.

I'm so sick of winter/cold weather I could scream. ENOUGH!

If they're not in leaf, you can put them in full sun, which will hasten bud-break. Do avoid placing a plant with foliage that emerged under low light conditions directly into full sun to avoid photo-oxidation (sunburn) of the foliage.

Bud movement or bud-swell precedes the spring flush of foliage. When you look at buds in the spring and thing to yourself, "something is about to happen" that's buds-well. Soon, color will begin to show at the tip of the bud, followed by the beginning of the leaf's emergence. A week or 2 before leaf emergence, during bud-swell is when you want to do your repotting/root pruning and structural pruning.

I try to keep my maples cool/quiescent as long as I can. Once leaves emerge, it's important to keep the plant in good light. If you don't, you'll get some horrendously long internodes which can quickly spoil the future of the plant, or at least force you to make some pruning decisions you might not otherwise have had to.

I've got some maples with buds starting to move now. I'll get after the pruning this week & start on the repotting next week - I have some time set aside before & after Easter to work on that.

Al

Thanks again, Al. Was planning to begin the root pruning and repotting this week when I began considering temperatures. If the past is any indication, I can expect more nights with some freezing temps. Given that you are repotting now in your weather, I assume the temp is not a consideration. But ...should I take any special precautions after the repotting? Shelter them from winds, for instance? Keep leaves pulled up around the pots?
gary

Temperature is a consideration to the extent that you don't want to expose opening buds to freezing temps, and you want to make sure the roots don't freeze after you repot. If you repot while the buds are still closed, and set the plants on the ground out of the wind after the work, they should be ok down to close to 25*, because of the warmth rising from the earth. Mine are in an unheated garage & safe until they start to put on their spring flush, at which time they're outdoors whenever the temps are above freezing. There are various strategies that would help keep roots warm and slow transpirational loss from the top of the plant. Just about anything you do in that direction would be helpful (like those you mentioned) - even if not always completely necessary.

Al