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Los Angeles County milkweed and tropical MW info

Posted by Need2SeeGreen 10 (SoCal) (My Page) on
Thu, Nov 7, 13 at 16:03

I offer this info as coming from a good source, though I am not sure how/whether it all applies all over the US. I hope it won't start a fight, I think we all want to do what's right for the butterflies. I just thought this might be interesting/helpful.

Here are excerpts from an email exchange that I found helpful, for LA area gardeners (I am leaving off the name b/c I didn't ask if I could use it). I had asked about 3 milkweeds,
California milkweed (Asclepias californica)
Woolly milkweed (Asclepias vestita)
Woollypod milkweed (Asclepias eriocarpa)
A. fascicularis
A. erosa

" The three species you mentioned all have occurrences in L.A. County, as do A. fascicularis and A. erosa. [... I took out the name of the seller, I think there is a rule here about that? If not, ask me and I'll blab.] typically sells seed of these species. If you get in touch with them, please mention that you�re looking for seed that is sourced from as close to L.A. as possible (they likely carry many seed lots that are sourced from northern CA). However, I should mention that milkweeds are notoriously difficult to maintain in pots. It sounds like your tropical milkweed is doing well, but I can�t guarantee that these natives will thrive in containers.
...
[I had asked about these.] Those orange aphids are �oleander aphids� (Aphis nerii). They�re not native to the U.S. but are now well-established and are a pest of milkweeds across the country. It�s amazing that they located the plant on a 3rd floor balcony! Or, maybe they were already present on the plant or in the soil when you purchased it� So long as monarch caterpillars aren�t also present on the plants, you could potentially use insecticidal soap to control the aphids.

Yes, it�s true that tropical milkweed (A. curassavica; ASCU) attracts monarchs. There is nothing about tropical milkweeds� chemistry that is inherently harmful to monarchs. Monarchs use tropical milkweed as a host plant in Central and South America where it is either native or naturalized. Female monarchs readily lay eggs on the plants and caterpillars complete their development without any problems. One major difference between ASCU and native milkweeds is that it�s a perennial, evergreen species whereas the majority of North American native milkweeds are deciduous and don�t have foliage during late fall and winter.

The concerns that scientists have raised are about tropical milkweeds� potential to 1) harbor spores of the protozoan parasite Ophryocystis elektroscirrha, 2) cause monarchs to breed outside of their regular season, and 3) cause monarchs to persist in areas longer than they usually would. I�ve attached a short newsletter article by a monarch researcher in Georgia, that provides a good summary of these concerns.

In areas with mild winters (such as southern CA), the plants typically have foliage year-round and thus there is potential for parasite spores to accumulate. In comparison, native milkweeds� foliage dies back over the winter and the plants re-emerge in the spring.

Regarding (2) above, there is evidence that monarchs are breeding on tropical milkweed in Texas and Florida during the late fall and winter, rather than migrating to Mexico. And, there�s concern about the presence of tropical milkweed in coastal California near monarch overwintering sites, because it�s thought that monarchs may be enticed to lay eggs on the plants, outside of the regular breeding season, and the caterpillars then won�t likely be able to complete their development because of cold temperatures. In summary, due to these concerns about potentially negative impacts to monarchs, we focus on promoting the planting of native milkweeds.

If you want to keep your tropical milkweed but minimize/avoid potential negative impacts to monarchs, you could cut it back at the end of fall so that spores can�t build up and so that the plant isn�t available for monarchs to lay eggs on outside of their regular breeding season. And, you could consider cutting off the maturing seed pods, to prevent seed dispersal."

If anyone wants the newsletter, I can try to send it. I thought this was long enough.


Follow-Up Postings:

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RE: Los Angeles County milkweed and tropical MW info

Thanks so much for this information, needtoseegreen. "The three species you mentioned", is that the newsletter you're quoting? I have been concerned about planting non native milkweed so I'm very glad for this post. I grow the milkweed that is native to where I live in So. Cal., if was growing in the yard for decades and I didn't know what it was until 2 years ago. Luckily the roots survived my weedings.

It makes sense not to fool around with mother nature and grow non native milkweed. I'm not surprised with the findings you listed from the newsletter. I have read about the toxicity of the "milk" varying and that So. Cal Monarchs aren't used to the toxicity level of tropical or other non native MW's, but I have no opinion because I don't know for sure. I would trust what Monarch Watch says on it.

The Monarchs that visited my yard last year when I tried a small plant of tropical in addition to the native (A. fascicularis) didn't lay eggs on the tropical. The tropical didn't do well in my heavy clay soil either.

Could you please forward the newsletter to me? I'd be very interested. Do you think they would mind if you mentioned them here?

I don't recommend using anything but water on the milkweed, because even a tiny amount of bleach in water will kill the caterpillars on contact. I found this out in my cat raising indoors for the first time starting a few weeks ago.

The newly hatched Monarch cats are way too small for anyone to notice, they are extremely small and are hidden under leaves, or can be embedded in the tender growth at the top of the stem. Insecticidal soap would kill them and leave a toxic residue (to them). I recommend crushing the aphids, and wearing latex gloves, they stain the skin. Hosing them off would be hard on the new cats and would likely wash them off too.

May I ask what MW species you grow? since you're in the same growing zone and area as myself. Any way to find out if the other species you listed (other than A. fascicularis) are native to the L.A. area? Any So. Calif. milkweed and Monarch breeders who read this, could you share what species of native MW you grow?

I am battling black mildew on my A. fascicularis leaves, and pulling off the affected leaves daily. It's a huge task. I need to keep a clean food supply for all the tiny cats I have brought in. Today I picked about 5 stem tops and found 4 more tiny cats, and the nights are getting too cold for them. Just the problem that the newsletter addressed; tiny cats hatching in weather that is too cold due to abnormal breeding spans encouraged by the non native MW species. (I get the impression that tropical MW to a Monarch is like catnip to a cat) Sadly all the nurseries, even Home Depot carry these non-native MW's, and I think they have helped create the OE problem.

The cats I raised last December-January all emerged as OE infected butterflies. The reason for this (according to what I've read) is because since the plants have been visited all season by butterflies, all that "foot traffic" has raised the probability of contamination of the plants and egg by the microscopic OE spores. The unnaturally long breeding season puts Monarchs in a perilous position not just weather wise, but disease wise.

Sorry this got too lengthy. This fall I'm dipping the milkweed used for feeding (clear of eggs or tiny cats), in water with a few drops of bleach for 10 seconds, and rinse it well. The 2 Monarchs I released today had questionable looking thoraxes (possibly OE infected), I was torn about releasing them. They were not raised entirely indoors. I need to get an inexpensive lighted microscope to check for OE, any suggestions where to get one, anyone? Thanks.

It didn't work for me to raise the eggs on the narrow leaves, the larvae all got black death or NPV (or?) at various stages. Now it's the cut MW in water, tons of work and I can't disinfect the MW that have eggs on them. I'm worn out! It's a full time job. Feels like changing baby's diapers all day long. :)


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RE: Los Angeles County milkweed and tropical MW info

Wow, you are doing a lot of great work!!! I actually don't know much at all about raising monarchs -- when I originally planted my MW, I was just hoping to *see* one or two of them!

The thing is, maybe since I was on a 3rd floor balcony, I never did see any butterflies. And then I found out it was the wrong kind for my area, so I pulled it all out. Right now, I'm not growing any MW at all, which since I don't get much butterfly business, I guess is okay. I'd rather grow none than the wrong kind. Still, it is a very nice plant -- I love things that grow without too much coaxing! If I get my hands on seeds from one of the kinds that the Xerces website recommends for my area, I will try again for sure, even if they don't like pots. (Confession: watching the seeds pods burst was better than free cable! Those seeds sure get around. I was pulling sprouts from my other pots for months, and still get one or two.)

By the way, the info I put was from a very nice email response that I got, it was not from a newsletter. I pretty much excerpted all the really juicy parts here already.

I will check out this other Monarch group that you mentioned, they sound very cool. I sure hope we can help get things moving in the right direction. It sounds like you are really doing a lot, and I wish you the best of luck in raising your butterflies. I hope I can see one soon! They are so beautiful. Me, I am happy when I see a moth.


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RE: Los Angeles County milkweed and tropical MW info

Oops, I forgot to say, I never did use anything on those orange aphids. I felt bad for the plants but I wasn't sure what to put on them, and in the end, they didn't die from the aphids anyhow. It seems like a lot of times, when something gets infested, if I wait a while, the situation resolves itself. I am sorry about your mold, that sounds very annoying!

Oh also, to the person who wrote to me for the A. curassavica Silky Scarlet seeds, I will try to email you back (I was a little confused but I'll just give it a try).


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RE: Los Angeles County milkweed and tropical MW info

Need2SeeGreen, thanks for the information above. I have some native milkweed growing in pots. The seeds just got in the pots all by themselves, I didn't plant them. The milkweed is doing fine in pots with no care. If they had been pruned and fed, and not in small pots, I bet they'd be great. I think you will have no problem growing (native) MW in pots, give it a try and I bet you will see plenty of Monarchs!

I read somewhere the other day "plant it (milkweed) and they will come" :) Monarchs, that is, and yellow aphids of course. Monarchs can smell milkweed for many miles away-they'll find you.


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RE: Los Angeles County milkweed and tropical MW info

Awesome!! I will give it a try when the chance presents itself.

By the way, someone had emailed me for seeds, but I didn't have an email, and I tried to email them back via gardenweb and I don't think it worked, since I didn't hear anything back yet.

Maybe they should send me an actual email?


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RE: Los Angeles County milkweed and tropical MW info

Needtoseegreen,
If you visit the seed exchange forum, there is a thread for "Adopt a Milkweed Newbie" number three. You can request to be adopted by someone in your climate or region who is already growing milkweed and could provide you with appropriate seed. I would specify that you want native species, if that is the case. I could send you seed, but I have a. Syriaca, tuberosa, and incarnata, which it don't think are native to CA.

Good luck.

Martha


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