Thank you for posting, I was not aware of that.

I have A. incarnata (swamp milkweed) in my garden, not the tropical milkweed.

Oh boy.
I have both swamp milkweed and Asclepias curassavica.
Last year I pulled out as many seedlings and dug out as many clumps of Asclepias curassavica as I could, because they were overtaking my garden. I will do the same this year.

I am having swamp milk weed poking up everywhere in my garden and the garden next door though. I have to keep the number of shoots down to the minimum.

Yes thank you for posting. I am sure many people will respond by getting rid of the tropical. I know I and others have noticed a drastic drop in numbers of Monarchs.
I grow A. tuberosa in the garden but I leave the natives wherever possible. It is easy for me since I live out in the country. (I let the pods mature so that the seeds blow in the wind)

I never liked the tropical milkweed much. Think the article said it was only a problem in the south of Texas where it was a perennial and they stopped and wintered there and laid their eggs. I heard that the ones that wintered in the Caribbean or made the flight from the end of florida were not making the flight there either and the butterflies were getting weaker.

I have native antelope milkweed and others that I encourage. They are all native to my area.

I thought I also read that the tropical was the lowest in the toxic alkaloids that the cats eat which are stored in their body to make them taste bad/toxic to birds. Did I make that up ?

I looked this up and found conflicting information, seems all the data isn't in and its still being studied. From what I read its the southern areas where the non migrating monarchs lay eggs that is the problem and native species are better.

One thing I can never get my mind around concerning the talk about a shortage of milkweed is that I see native vine milkweed growing around here everywhere. Its like bindweed, if there's a fence or something for it to climb on, sooner or later an infestation will happen unless you stay on top of weeding. Its considered a noxious weed by farmers and gardeners, you don't want the stuff and its is impossible to get rid of once it takes hold. So on that note, how is it possible to have a shortage of host plants? I asked this question on a forum one time a while back and there was no response but I still wonder about it.

Here in Oklahoma, if you have a fence chances are sooner or later you will have a vine milkweed growing on it, we played with the pods as kids where all the yards had chain link fences.

Thanks for sharing, I got tropical milkweed from a swap last year.

Please post in the Milkweed forum. I bet most would appreciate this article.

TexasRanger,
The shortages of milkweed plants is occurring throughout the Midwest where so much of the previous prairie has been converted to crop land. Until recently, even with so much land converted to crops, Monarchs did OK. That is because there was still a significant amount of milkweed growing in the fields between the rows of corn or beans, etc. However, with the rapid increase in the use of genetically modified, herbicide resist crops, and the widespread use of specific herbicides, those milkweeds are being wiped out. Now Monarches face endless miles of fields without a single milkweed plant, or any nectar sources, either. It is a problem for all native pollinators, not just Monarchs.

Martha

Yea Martha I know that but I've just always wondered about the vine milkweed, what I meant was is it a milkweed they find easily available since its so prolific and common to the chagrin of many farmers, gardeners and landowners? I think the shortage of pollinator plants might be a bigger factor around here because that vine stuff seems to grow anywhere and you can't get rid of it even if you want to because the roots are so tenacious, it invades fields and will climb up anything. It commonly grows along fence rows and this whole state is divided by fence rows from one end to the other so it just seems like.... well go figure. Anyway, it was just a thought because no one ever mentions it when the subject of the shortage of milkweed comes up.

I've had a plants come up along the fence here in the city from seeds blown in several times but I finally got rid of it before it could take hold each time. It looks like bindweed so its hard to tell the difference at first but it makes no difference because one is as bad and hard to get rid of as the other and they usually sneak in around a shrub so you don't notice it until its large.

TR10 - I had never heard of milkweed vine so was curious to learn about it. Some Googling around turned up the article in the link below - it looks like this vine is indeed important for the Monarchs in the central plains area where it grows. I also found lots of references to a somewhat similar-looking invasive vine called swallow-wort that is detrimental to the monarchs - see:

http://www.fs.fed.us/wildflowers/pollinators/Monarch_Butterfly/documents/Swallow-wort_flyer_MJV.pdf

The decline of the Monarchs is very obvious here the past few years, so I hope they will be able to make a recovery eventually!

Here is a link that might be useful: Milkweed vine and Monarchs