Wintering JBP and Zelkova serrata seedlings

(gaxelson) #1

I raised these questions with Jonas, who had some helpful input but he also suggested I post here for other ideas. The topic is some seedlings that were planted over last winter and germinated in the spring and the best way to get them through their first winter above ground. I’m located in the Norther Virgnia suburbs of DC - which straddles zones 7a and 6b.

So first are some Japanese Black Pine seedlings. They’ve been out of the flats and in the recommended 4" pots since late spring - I’ve attached a picture of two. The question is, what do you recommend for overwintering them in terms of shelter, temperature range, etc? I know the parameters for a mature JBP with a substantial root system, but these guys still look a bit fragile.

Second, if you happen to know, the same question applies to some Zelkova serrata seedlings that germinated around the same time and are in 4" pots of their own. Thanks.

(jdkirby) #2

Typically in your zone you can winter on the ground, near the house outside. The critical thing is to be sure that you don’t let them get really dry when thawed. Keep them moist. If under plastic, same thing, don’t let them get too dry.

(gaxelson) #3

Thanks for the good counsel. What do you think about putting both the Black Pine and Zelkova seedings in a cold frame where I’ve just begun stratifying some Trident Maple seeds? It doesn’t quite abut the house - it sits against the screened in back porch, which does. I mounted a remote temp and humidity monitor inside of it last winter, it offers wind and precip protection and typically runs 7-10F warmer than the outside air on cold days.

(Jonas Dupuich) #4

The cold frame would be good for cold snaps when the temp drops, and stays below, freezing for several days, or for when it drops into the 20s. If it drops much below that they’ll need even more shelter.

(gaxelson) #5

Good plan. We don’t drop below 20 often, but the garage works well when it does for my more mature trees and makes even more sense, as you point out, for these seedlings. Thanks