I would like to try growing butterfly weed, asclepias curassavica, a. incarnata and a. tuberosa from seed in pots, and let them grow over the winter to be planted next year. Does this sound feasible? Do the perennials need a dormancy period like some trees do?
Thanks for any advice,
Maureen
Perennial dormancy period for butterfly weed?
Maureen, I read that they are herbaceous perennials. They lose their leaves duing winter but come back to life again in Spring. They are a bit late though and won't get new leaves until April.
They will go dormant in the winter. Try not to leave them in the pots too long, they have a taproot that doesn't like to be disturbed.
I am in zone 5a, similar to yours, and I have asclelpias tuberosa in the ground. I would say you can let them grow over the winter indoors perhaps, but I would not leave the pots outside over the winter. The soil in the pots will be much colder than the soil in the ground and might not be suitable for keeping them alive. Maybe you could leave them outside for a few earlier "light" frosts so they go dormant, and then keep them in a cool spot over the winter without letting them get a hard freeze.
I never grew them from seed so I'm not sure, but some perennial seeds grow extraordinarily slowly. Maybe you could start the seed in the fall and then transplant out in the spring? If they are slow growers, that might work well. However, the taproot issue might be a problem as per fly_girl's comment.
I have seen them for sale (adult plants) in 1 gallon pots.
I wouldn't try to keep them from going into dormancy by keeping them indoors over the winter. I think your best bet, if you want to start them now, would be to keep them in pots until about 8 weeks before first frost, then put the young plants in the ground for the winter. If you do want to keep them in pots, you'll probably want a cold frame. The taproot shouldn't be too much of an issue growing in pots, but if it gets through the bottom of a pot, and you have to snap it off, you'll have to nurse the plant back to health.
-Greg
I've started the Tuberosa from seed in deep flats. As soon as they get true leaves I plant them directly in the ground.
I have a 'nursery' bed with deep, loose soil. Very early the next Spring I lift them, digging deeply with a spading fork being careful of the tap root which can go in any direction. Plant the seedlings pretty close together, maybe 6 inches apart.
I think the key is the loose soil and the early transplanting.
I've had pieces of broken root send up new plants in the nursery after I moved them all out.
I don't think they would profit by spending the Winter indoors.
They self seed well, too. Those are easy to transplant when the true leaves come in.
Andy P
Thanks everyone, based on all this info I've decided that if I grow one in a pot, it will be a very big pot and will stay there because I don't want to disturb that taproot.
I also think I will let it overwinter in the garage where it gets cold enough to allow dormancy w/o freezing the roots.
Thanks again,
Maureen
You should try some direct seeding too, they're pretty tough plants.
I think I will next year. In fact, I am considering a cold frame and soil heating cables so I can do some direct sowing earlier.
Maureen
They freeze to ground level for me every year--also easy to root them right in the dirt of the garden where you want them to stay.
I wintersowed them (outside in containers). They germinated, have been transplanted to the garden, and are about 6 inches tall now.
Karen