Thanks, Susanlynne! I had what I thought were Monarchs fly by my garden earlier in the summer, although there is another common AZ butterfly which can be mistaken for a Monarch and I'm not sure if I could tell the difference.
I'm not sure which milkweed would do best in my yard, either. If there is one that would do best in the shade and would like periodic flooding, because I have flood irrigation, that's what I need. I don't have a lot of sunny areas, although I have an area with filtered sunlight. I do have a few sunny areas that I can put it in the garden but sunny areas are at a premium.
If you do get some extra seeds this fall, I'd be happy to send you an SASE. I can't plant anything until fall, anyway. Nothing but okra would grow in this heat.

Do you want to stay with native milkweeds, other than the Tropical Milkweed, which is most likely going to be perennial in your area, not mine (I grow as an annual and collect the seeds)?

One that is native to the US, but not to Western USA (you can still grow as an ornamental), is Asclepias purpurescens, aka Purple Milkweed. The flowers are to die for. It can be difficult to establish from seed, and may take several tries, like it did for me. A friend finally gave me two plants that I am feeling comfortable will do well in the location I have them in. The problem for me was that the snails and cutworms LOVE this species, and I lost several plants before getting these two to survive. For me, it was planting last month - in a sheltered location beneath a pine tree. Knock on wood, the beasties have yet to find them. It is a beautiful milkweed, and about the only one that will do well in shady sites.

A. incarnata aka Swamp Milkweed, would do okay in part shade, but probably won't bloom. It has pink blooms and likes a moist, well-drained soil.

There are also a couple of milkweed vines that do well in part shade, but can easily get out of control unless you remove the flowers or seedpods before they ripen. They are Cynanchum laeve, or Blue Sandvine, and Sarcostemma cynanchoides aka Twine Vine. Sometimes the Monarchs will bypass them, though.

I have to say, my Tropical Milkweed is planted in part shade and is blooming its head off right now. So it will bloom in the shade and doesn't get real leggy either.

There is a milkweed, A. variegata, that blooms a beautiful white, but it is very hard to find. It does well in part shade, but good luck finding it. A friend in Tulsa is trying to establish a colony of it, but so far no pollination has occurred on her blooms, which is another problem with this milkweed. Difficult to start from seed, and to grow it large enough to sustain it. It is very rare, and populations have disappeared from its native habitat due to habitat destruction.

I am not sure what butterfly you saw that resembled a Monarch, but a good guess would be a Queen, which is in the same genus as the Monarch and its larval host plants are also milkweeds. The Viceroy is a Monarch mimic, but I think they are very rare in your area.

I am attaching a link to the Butterflies and Moths of North America website, and specifically to those butterflies seen in various parts of Arizona. You may also want to include other butterfly larval host plants eventually, like those for the Black and/or Anise Swallowtail butterfly, which eats Fennel, Dill, Rue, and other plants in the Apiaceae family. You should also get the beautiful Gulf Fritillary butterfly and in your zone, there are many lovely passion vines you can grow to attract them to lay eggs. Just don't use the red flowering types because they are lethal to the caterpillars. I grow 2 of these - the Passiflora incarnata and P. 'Lavendar Lady'. Incarnata is a rampant, aggressive vine you may not want, but there are lots of different ones available. 'Lavendar Lady' is just that, much more of a lady in the garden than incarnata.

I also invite you to look at and participate in the Butterfly Gardening Forum here at GW. We don't have anyone that I can think of that is from Arizona, so your input would be fantastic!

Hope this helps some.

Susan

Here is a link that might be useful: Butterflies and Moths of Arizona

Susan - I had several native milkweeds at our previous home, and intend to have them again. Pineridgegardens.com - over in Arkansas - has A. variegata and many others listed on her site.
Carol

Here is a link that might be useful: pine ridge gardens

Carol, you are right! Maryann has listed this milkweed species for so long as being "out of stock", that I never did think she would never offer any for sale. I notice she has them for fall 2011, and did not have them in her spring 2011 catalog, nor any previous years.

I wouldn't recommend this plant to a beginning gardener, and I am not saying that you are a beginner, Tracy. Just that they can be difficult. They are absolutely beautiful in bloom, and from a small plant, would probably bloom after 3 years in the ground. The flowers are extremely difficult to pollinate as the structure of the flowers cause the bees to become trapped in them and they are unable to extricate themselves in order for pollination to occur.

They are gorgeous plants, in danger of being lost in their habitat in several states, and rarely reported in others. So, in that case I would, contrary to the above recommendation, suggest trying them to see if a colony can be established in a home garden. They do spread slowly by underground rhizomes.

Susan

Thanks, everyone. What would be the easiest milkweed to grow for one year, and possibly, take some seeds with me to grow in OK? There is a good chance we'll be leaving next fall to move to OK. Don't know where yet, hubby needs to find a job. Looks like he will defend his dissertation sometime in September, 2012!
We have a lot of citrus and giant swallowtails. Those are so beautiful. I really need to plant more parsley, dill and cilantro this year. I just started to really have a chance to pay attention to the butterflies and it's so fun!

I am new to this and am in OKC as well. I cannot get clear on how to acquire the correct bulk seeds and how to plant them. I note that Sue is in OKC as well and if she can contact me my office is 405 943 4413 and I am an MD. Ask the girl to put your through. My wife is used to teach botany at OKCCC but I still need help on this. I am a member of the Sierra Club. Dave Brinker

Kayakker...Monarch Watch is selling flats of milkweed. You might check those out.
Monarch Watch Market

Because I didn't know what I was doing, I left the milkweed to rot beneath the aphid infestation. I should have pulled it out so they would not have a chance to repopulate this year. Aphids be bumped, I'm gonna plant anyway.

Will sowing seeds indoors help give them a boost for the season? I know, now, that I can spray water or just squish them. Never dealt with aphids before that milkweed plant last year.

Wait. Long sensitive taproot. I'm not experienced enough to transplant these.

Bon, I had them too. Squishing is really the only success I had getting rid of them.

That's just so gross. I hope Monarchs are not ingrates.

I get very few (if any) monarch cats. I just chant to myself, "if you build it, they will come" :)

I have many options regarding space. Is it better to plant randomly throughout instead of a small crop of them? Easier for me if they are together, but I'm willing to 'seek and water' if that would help.

hmmm... butterflies congregate along tree lines, don't they?

They congregate wherever the flowers are. I see more butterflies in the pasture where the flowers are mixed in with tall grasses than in the treelines. Our treelines are shady and there's not much milkweed (or anything else in terms of flowers) there in the shade. I mostly grow flowers in larger drifts so the butterflies can flit from one to another, but they'll hit spots with one or two flowers and then move on to find the next spot as well. If we're talking about all butterflies, nothing attracts them more than henbit in early spring and zinnias in summer. I try to avoid the newer hybrid type flowers and grow old-fashioned heirloom types.

Lisa, I almost never see monarch cats, but they have to be someplace nearby because we have lots of monarch butterflies in the summertime.....even if I don't see them in the cat stage.

Bon, I seem to have a number of gardening gloves and never, ever wear them. I found them to be a good squishing covering!

Don't forget some mums, the daisy type if possible. The very busiest butterfly day I have ever had centered around my mums in October.

Okay, if I have time. They might hafta suffer with buckwheat !

Lisa, I have ? Oh. Lemme start another thread.