Hello, I have a bunch of Acer Palmatum seedlings that germinated this spring, and I wonder if someone give some advice about the best winter storage for them? I have a couple of options, but which is the safest? Unheated greenhouse, garage (kept at 4 degrees celsius -40 degrees fahrenheit), or outside in a cold frame? The temperature here rarely drops under -10 celsius (14 fahrenheit). Br - Johan
In your situation and if you do not have too many of them, my recommendation would be to plant the pots: place the pots into the ground for good root protection, in an area of your garden that does not get water logged during the winter. Gomero
Ok. Is it better to put them in a raised bed with mulch around, or just in my normal clay? Then another question, some of the pots have several seedlings in them (up to 4 in the same pot) and I want to repot them individually. Which is the best time to do so? Now, or later in fall (when dormant) or early in the spring (right before bud-break)?
Raised bed would be better than clay, but I am sure they would also be fine in the coldframe or unheated greenhouse you mentioned before. My local weather station reported minus 7.7°C as the minimum last winter and my seedlings were fine outside with no protection at all. Obviously I wouldn't risk -10°C or lower without some extra protection, but I reckon the coldframe would be enough in your situation. You could even put the pots in a box in the coldframe and cover them with mulch or straw or dried leaves or something. As for the seedlings, I think spring would be the best time to seperate them. There is very little root activity at this time and the storage root(s) will be quite woody and easy to deal with. Last year I had a seedling growing 1cm from the trunk of an established potted maple, inbetween some roots; I removed it this spring just before bud-break very easily. If you think they need repotting before the spring then I would do it as soon as possible to allow them time to establish and harden new roots before any freezes.
I vote for the raised bed with mulch. These are hardy little plants and that should be enough protection, while still allowing free drainage for the roots.
In Sweden you get a lot of rain, so it is probably better to favor a situation with good drainage. Please read the FAQ on Root Pruning, the advise there is also applicable to repotting Gomero
Good thread, the one in the FAQ. I was leaning towards re-potting this fall, but didnt know if there was some special care needed when its seedlings. I am a bit worried at the moment though, because the seedlings are still putting on some growth, and still very much in "soft-tip" state. Is that a problem for re-potting? I dont plan to do any root pruning, because they dont have enough roots to fill their pots yet.
Hi, I'm a newbie to Japanese maples. I don't have much space to do a raised bed or bury the pots. Can I just put them in my unheated garage instead? Would they be ok in there or do I still have to insulate the pots? I have about 20 cultivars all of them are in the black plastic pots like the ones in nursery stores. When is the best time in the year to take them in and then take them out?
I’ve been placed my JM in my unheated garage (btw 30~45 F in cold months) for over wintering for years, I bring them in when outdoor temp drops to 20~30 F and take them out when temp reaches this same range. I’ve learned the appropriate temp for JM defoliation period is btw 15 to 45 F. Good luck.
