I bought a clematis collection from Park Seeds this spring. They were bare-root and pretty darn tiny, so I put them into 1 gal pots. They have been growing and growing, but they still didn't look big enough to fend for themselves for the winter so I haven't put them in the ground. Now what do I do with them? I have an unheated greenhouse, but it gets pretty chilly up there in the winter.
Overwintering Clematis
I copied this from Donahue's Clematis Nursery website,
OVERWINTERING:
It is important for Clematis to go through a dormant period. A cool treatment for a minimum of 6 weeks will provide this needed dormant period. Plants should be cut back to 8 to 12 inches and all leaves should be removed during the first two weeks of the dormancy to maintain a clean area, free of plant debris. Fertilizer needs to be cut out 2 or 3 weeks prior to the dormant period to reduce the salt levels in the media. A drench of Fungo or Clearys 3336 should be applied after the plants are defoliated.
Here is some more info that I found on the web from a person that over winters their Clematis seedlings in a greenhouse in England. Hope it helps.
"Overwintering Seedlings in the Greenhouse"
"I no longer worry about general light, winter frost, too much, if that's when they happen to germinate. If you can protect germinations and seedlings from the worst of it, fine, a little heating is very helpful. I store my pots both in a cold greenhouse, under the staging, covered with fleece; and also outside, exposed to the elements, awaiting germination. When the seedlings appear, if it is particularly cold outside I will bring some into the house (softy). But by and large the seedlings will come through a light frost ok. If it gets seriously cold, and frozen, and the outlook is 'more of the same', bring them in straight awaY. Don't allow seedlings to be unnecessarily frozen.
Of course, you can plan to prevent frost if you wish to, by various heating means. Again, this is only as pertaining to my location in England, where we have relatively mild winters - usually, but not always! (As seems the trend in recent years, last Autumn, 2000, was extremely wet in the UK; and very mild, so far). (Well, now we're in Spring I can tell you Winter was cold!; and floods all around the Country!)
Your chief concern are seeds which actually germinate during a very cold spell. It can be useful to have sufficient heat available to warm things for a shortish spell. Or you might choose to selectively bring new germinants indoors awhile, to tide them over the harshest conditions. Having said that, even newly-emerged seedlings have, on occasion chez moi been surprised by sudden cold, and have been frozen, but, on thawing, have nevertheless produced a new shoot, or just resumed growth. Clematis seedlings, generally, are very tough. You won't lose many to reasonably modest levels of frost, as long as they are in the greenhouse, at least. But it is prudent to perhaps pamper your most prized germinations for a while, partuclarly if the cold persists, just in case.
I am referring to conditions in Manchester, UK, where our coldest spells (I shouldn't say this) are usually relatively short in duration. Once seedlings develop the beginnings of a root system they are already usually able to withstand some reasonable frost, to a significant degree.
Any seedlings germinated and potted earlier in the season, which have established to some extent, will usually be fine through winter; the foliage on these seedlings will mostly die down and rot. The vines will often persist, sometimes, carrying live buds in the axils (between the leaf-stalk and the stem). On very young seedlings, if the foliage is going to rot anyway at the end of the season, it is best to remove it by pruning even young plants down quite severely. Don't worry; even young plants will surprise you with large-sized shoots or buds in due course. If you're a bit reticent to prune young plants at the end of the season look at the photos on the Growth Gallery page, you'll see how keenly they come back in Spring (and before).".
This message was edited Aug 28, 2004 2:05 PM
Thank you for the response Shirley. I'll give the gh a try and try not to molly coddle them too much and hope for the best. I shy away from pruning because I don't know which groups the plants belong too. Why can't they all be the same?