What have you done with all of the tender perennials you bought this summer? Are they in the compost heap? Have you left them where they were planted in hopes of a mild winter come-back? Did you take cuttings? Have you filled your garage/basement/livingroom with plants in pots and roots in bags?
We can answer “Yup!” to all of the above but obviously we have the big advantage of a working greenhouse that we can fill with stock plants, cuttings and more phormiums (a.k.a. New Zealand flax) than any garden could ever need. When Margaret Roach came through the greenhouse, she noticed the phormiums (that Gail so cleverly tried to hide behind other plants so it wouldn’t look like we’re hoarding them) and mentioned that she winters hers over in the basement. She also winters her cordylines (Cabbage palm/Cordyline australis) in the basement and I’ll bet you a dollar that her plants look a lot healthier than ours. I have always suggested a cool but bright winter spot for things like phormiums. – Not that I don’t believe Margaret, but has anyone else kept them in the dark?
Geraniums (Pelargonium) are another plant that can go “down cellar” (as we Rhode Islanders say it). You can leave them in their pot, cut them back a bit and allow them to mostly? dry out. Or you can un-pot them and hang them upside down by their naked roots – but that sounds a little like hortitorture to me. I have a vague repressed memory of losing geraniums that I kept (forgot) in the basement and wonder if anyone else has tried either of these methods successfully? We take cuttings earlier in the fall and keep a few stock plants in the greenhouse where they inevitably get leggy or weird from growing when they’d much rather slow down. [Here's a tip you probably already know: When you take geranium cuttings, let them callous overnight in an open plastic bag before sticking them in the rooting medium.]
Gail loves tender salvias more than anyone else I know so we winter over as many as we can make room for – mostly by taking cuttings. She’s had some luck with salvias like S. guaranitica and S. uliginosa wintering over in her own garden so we’ll leave a couple in the Display Garden this year too. You never know – every once in a while even a forgotten dahlia comes back after a mild winter. We will leave the Savias standing for now with all their own woody protection and we’ll mulch them with shredded leaves. Fingers crossed.
The potting shed cellar is fairly warm (around 60°F) because of the furnaces but we do keep 4 o’clock (Mirabilis) tubers, gladiolus bulbs, dormant lemon verbena plants and dahlia tubers (in paper bags this year – fingers crossed) down there.
So, what have you done with your tender perennials?