Armchair botanizing for Extreme Milkweeds (Asclepias)

[McDonough]

Love them or hate them, you cannot deny the beauty of intricately crafted milkweed blooms, often deliciously perfumed and beloved by butterflies.  Some Asclepias are well known invasive weeds, many are course stalwart plants more suited to a wild prairie garden, and relatively few may gain admittance to a rock garden.  The North American west holds a number of fascinating dwarf Asclepias species, most will be challenging to cultivate.  Let me start with one of the most remarkable dwarf milkweeds, the rare Asclepias uncialis, or Dwarf Milkweed (to that common name it holds more than true).  There are two subspecies; ssp. uncialis, and ssp. ruthiae.

http://plants.usda.gov/java/profile?symbol=ASUNU2
...ssp. uncialis flower close-up
http://calphotos.berkeley.edu/cgi/img_query?enlarge=0000+0000+0504+0481
...ssp. ruthiae plant out of flower
http://plants.usda.gov/java/largeImage?imageID=asunr_001_ahp.tif



I found the following document, Rare Plant Surveys on Fort Carson 2006-2007, Colorado State Univ., 70 pages, 5.5 MB PDF, with information on Asclepias uncialis ssp. uncialis with two good photographs.  Since the large multi-megabyte PDF download might be too slow for some viewers, under the fair use provision I include two screen captures (above) from the document showing this rare and extraordinary minuscule plant, small enough for a trough if it could be cultivated.  The coins give a good sense about how tiny the plant is.
http://www.cnhp.colostate.edu/download/documents/2007/FtCarson_FINAL122107.pdf

[McDonough]

The US Forest Service has a very good page on Asclepias uncialis ssp. uncialis (Dwarf Milkweed, Circle Milkweed).
http://www.fs.fed.us/wildflowers/plant-of-the-week/asclepias_uncialis.shtml

Their photo of this plant is by far the best I've found, what pure milkweed delight.
http://www.fs.fed.us/wildflowers/plant-of-the-week/images/wheelmilkweed/asclepias_uncialis_lg.jpg

Excellent US Forest Service document on Asclepias uncialis ssp. uncialis, PDF, 2.5 MB.
http://www.fs.fed.us/r2/projects/scp/assessments/asclepiasuncialis.pdf

[Hoy]

Some years ago I tried a couple of milkweed but they never survived.
Now I think I have to try A uncialis.

Mark, all the plants you present give me much pleasure but also much work

[cohan]

I love every milkweed, I think! None in my region... This tiny species is exquisite for sure, I've been drooling over several in Alplains catalogue for a while; Gardens North has some nice ones too, but of the larger sorts..

[Peter George]

About 6 years ago I germinated some Asclepias asperula seeds from Alan Bradshaw's Alplains, and I have managed to keep two alive and blooming. 2 years ago one of the plants bloomed spectacularly, and for 3 weeks it was covered with ants, various beetles and a very few butterflies. After some research I discovered that this plant provides migrating monarch butterflies their primary source of nectar as they migrate through Texas, where 'Antelope Horns' are most commonly found. My daughter took several pictures, and the one I've linked is by far the best. It's a lovely plant, spreading to about 1 foot and each year I've gotten between 2 and 6 flowers. And since the first year, when 4 simply didn't come back, the two I've still got have reliably showed up sometime in mid to late April, blooming in mid to late May.

[Booker]

Gorgeous thing, Peter. Many thanks for posting.

[stephenb]

Some years ago I tried a couple of milkweed but they never survived.

Nice plants! Would love to grow more - have tried and failed with many over the years - A. purpurascens, quadrifolia, tuberosa, rubra, syriaca, incarnata (several cultivars). However, I have one which I've had for over 10 years - I received it as syriaca, but I decided at one stage that it was incarnata, but I'm not sure (any suggestions).  The season's too short for seed to mature though...

 

[Hoy]

Peter, I like your Asclepias asperula! But it being a Texan, do you think I could grow it?

Stephen, if you can grow Asclepias it is hope for me too

[Peter George]

Trond, it's hard to say. I have it growing in almost pure gravel, facing southwest. It needs a lot of sun during its growing season, which is really from early May through late August. It tends to go dormant around Sept 1 each year. If you have a spot that gets sun during the summer on a fairly consistent basis, the wetness shouldn't bother it. It might be worth a try. Just make sure you give it a lot of gravelly mix, with virtually no soil for 6 inches deep and 1 foot around. I haven't seen it show itself yet this year, which was the snowiest of the past decade or two. Last year we had a couple of January/February thaws, and yet it still did fine. Honestly, I think you ought to give it a try. It's easy to germinate too.

[Hoy]

OK, Peter, thanks!
I'll try it at my summerhouse too. There the climate is better - drier and warmer! In fact I need some summer flowering drought tolerant plants there - and if they attract butterflies that is a big bonus!

[Tim Ingram]

Like Stephen I've tried quite a few Asclepias from seed but haven't managed to keep them to flowering. They are completely fascinating plants with extraordinary flowers. The larger species do well; speciosa is very good with greyish foliage; syraica is really too much of a good thing, spreading rapidly underground and with rather squinney flowers, tuberosa has been glorious but not persisted. Having seen pictures of the more choice and small western species I shall persevere with trying them in deep gravel as and when seed is available. Meantime I will enjoy the photos!

[RickR]

Butterfly weed (Asclepias tuberosa) started easily from seed for me.  The little sausage of a root they produce in just a couple months is fascinating.   With all that stored energy, I don't know why they are so finicky about transplanting, but they certainly are.

The seedling on the right is Lead Plant (Amorpha canescens), with its long, horseradish-like root.

[Hoy]

Butterfly weed (Asclepias tuberosa) started easily from seed for me.  The little sausage of a root they produce in just a couple months is fascinating.   With all that stored energy, I don't know why they are so finicky about transplanting, but they certainly are.

Rick,
Are they fincky if you plant a potfull without disturbing the roots at all? Do other milkweeds behave in the same way?

[Lis Allison]

I have some (A. tuberosa) growing in pure sand and they are doing well. They are native here but only found in sandy areas. The roots are very brittle and very susceptible to rot which is probably why they are hard to transplant. Give the pure sand (at least 10" of it) a try. I'd be interested to hear if it does the trick.

[RickR]

I have some (A. tuberosa) growing in pure sand and they are doing well. They are native here but only found in sandy areas. The roots are very brittle and very susceptible to rot which is probably why they are hard to transplant. Give the pure sand (at least 10" of it) a try. I'd be interested to hear if it does the trick.

Regarding Butterfly weed, Trond, transplanting with a large soil ball intact would be a logical assumption, but I have no experience.  If you plant in sand, I might expect the sand to fall away from the roots anyway.  Maybe it would be better to seed in a a pot that will decompose so, the whole thing can be transplanted, or seed in a pot where you can remove or cut the bottom off when it's time to transplant.

Asclepias tuberosa is native here in the Midwest (USA) also.  They do mostly grow in sandy prairie habitat, but I have noticed them in dry clay based soil, too.  I think my climate is drier than Lis's and may account for the difference.  Or, I wonder if sand is just were they compete best, rather than a need.