Tuesday, July 18, 2006

Showy Milkweed (revised post)

My original post for today asked for an identification of this plant, which I'd never seen before. I've revised it since Ontario Wanderer has kindly identified it for me as a Showy Milkweed (Asclepias speciosa). In British Columbia, where it is native, its status is invasive/nuisance, but not currently legislated as noxious, although it is poisonous to livestock. We stopped to photograph the beautiful blooms on our way down the hill from the Mission Hills Winery in Kelowna (Okanagan Valley).

The U.S. Federal Highway Administration has an interesting web site on roadside vegetation management. It lists the Showy Milkweed under its Roadside Use of Native Plants database for Arizona. There is a caveat at the bottom of the web page:
Because the noxious weed lists have continually changed since we gathered them in 1994, we are not including them at this time. Not all States have noxious weed lists. Those that do, do not use the same standards of importance and are not comparable. States typically have included plants that interfere with agriculture (Canada thistle), or cause human health problems (poison ivy). Some States are now including a category of plants that invade and degrade the environment (purple loosestrife). Check with your State's Agriculture Department or Weed Scientist listed below. The noxious weed list can be used two ways on roadsides: 1) check to not inadvertently plant these invasive plants, and 2) note the plants you are legally responsible to control. Many States now check adjacent State lists to avoid planting their neighbors' problem plants. Because weeds do not respect political boundaries, and because by their very nature weeds continue to adapt and expand, monitoring and controlling invasives at State borders is a wise part of vegetation management.

7 comments:

T. Beth said...

It looks like a type of milkweed (Asclepias sp.) based on the characteristic flower structure. Unfortunately, I don't know the species.

chiefbiscuit said...

It's pretty in pink whatever it is! I have been away but have enjoyed catching up with you - friends of mine arrived in Vancouver today.

Ontario Wanderer said...

Asclepias speciosa or Showy Milkweed is what it looks like to me. I just found some planted in Hamilton. (See my June 28 Blog, third photo.)

François said...

Bonjour,
I can confirm it's an Asclepias speciosa: I have got one in my garden, here, in France... :))
It has an African cousin often met on the edges of Sahara: Calotropis procera. You can see it on the following pages:
http://pageperso.aol.fr/fmeignant/Calo.html
http://aceras-photos.over-blog.com/article-1386224.html
and: http://aceras-photos.over-blog.com/article-1413003.html

It's funny to see that the flowers are very similar between both cousins, as well as the shape and position of leaves.
Calotropis procera is also a very dangerous plant.
Amicalement
François

Nate West said...

I'm confused Showy Milkweed is native to British Columbia and it invasive there as well? Usually native plants aren't invasive?

JLLove said...

Lovely post and very informative.

Not sure why a native plant can't be invasive or obnoxious.

Kudzu is native in far east (I think) and I would certainly use those terms for it.

Pam in Tucson said...

t.beth - Thanks for the clue.
And thanks for coming by. The photos of Costa Rica on your new Firefly Forest web site are just magnificent.

chiefbiscuit - pretty in pink, indeed! I hope you have an opportunity soon to go to Vancouver and then explore the Rockies. In the mean time, make sure your friends send you photos of their wonderful new city.

o.w. - Many, many thanks for the ID. I've revised my post accordingly.