Have you seen butterflies around your building at all? Or on other plants and flowers on your patio? How long have you been growing your milkweed? When I first started my butterfly garden, it took 2-3 years before I got anything but Cabbage Whites. It may take time for butterflies to find you. Is your plant Asclepias currasavica? I've not grown that variety, but there are others on this forum who have had good luck with it, I think. Good luck.

Martha

Hmmm...always interesting to look at a question from another part of the country. Welcome!

So, I am putting my thinking cap on. There is lots of information on LA and monarchs and I have posted a few interesting links below. Monarch lab also has a PDF on monarchs in CA.

First, good for you! Planting plants for butterflies and Monarchs is imperative in CA. The Monarch population has decreased over 90% in CA. Specifically to your question, 'Silky Scarlet' is a cultivar of Asclepias curassavica. We tend to go by scientific names for milkweed because there are so many (over 70 in the US). A. curassavica does indeed attract monarchs and most of us find it does a very good job as a host plant. The article from the LA Times notes that it does work in CA as well. However, it discusses a phenomenom that is a problem in areas that do not freeze (thereby killing the plant). It can stop migrating monarchs on their way to their overwintering site and break their reproductive diapause (non-breeding state). So, they recommend using A. speciosa, which is a gorgeous plant. Since you are lucky enough to be able to grow it, I would use that.

Now, as to why you have no butterflies, there can be a lot of reasons. As Martha said, if you do not have monarchs passing your patio, you wont bring them in. Can you define "a bunch"? The more of a host plant you have in an area, the more likely a monarch will find them. They rely on chemicals drifting in the air as well as the shape of the leaves. So, if you have a lot of milkweed plants, momma monarch will key in on the drifts of chemicals in the air. More drifts, more likelyhood of finding them.

When did you start your plants? If you started them later in the spring or early summer, my guess is that by the time they were of good size, monarchs may have moved on to northern climes. Monarchs that migrate from Mexico and end up on the east coast and mid-west, return in early, early, spring to the pan-handle. Once it starts getting really hot, or the milkweed starts senecing, this forces monarch north. So, it could be the same in southern CA. Looking on earlier threads, it looks like December is prime monarch caterpillar season for you (look up Sherry from CA's posts under tdogmom. http://forums.gardenweb.com/forums/load/butterfly/gal121727495914.html)

So, you might just have to wait till December (if you didn't have the plants in then).

Good luck,
Elisabeth

http://latimesblogs.latimes.com/home_blog/2011/01/milkweed-for-butterflies.html

http://articles.latimes.com/2012/jul/10/local/la-me-ortho-monarch-20120710

Here is a link that might be useful: Monarch decline in CA

Thanks so much!! This was very helpful.

Martha, I've never seen any butterfles on my patio. (Aphids --though oddly not so much this year, some wasps, flies, and once, a ladybug.) I think the problem is, the half-wall is solid and there's not much air circulation.

Elizabeth says the butterflies need to "smell" or see the plants, so I put my biggest pot on top of another pot, so now it peeks out over the wall. It is setting out seed - a ton, actually.

I got the plant when it was already 3 feet high in its pot and of course it has to stay in pots. (But I can tell it would like more dirt, b/c one grew in with my jasmine, in a bigger pot, and it got huge before I ripped it out b/c it seemed like it was taking over. I repotted that one and it's the one sending out seed. It's mad at me right now, but I think it will survive. I don't let them root in other pots now.)

Pretty much nothing ever freezes here. It sounds as though I should grow that other kind. I will check out those articles.

Thanks again!