Have you tried using a sharp stream of water from the hose to knock the aphids off the plants? That usually works fairly well, although with an infestation as heavy as the one in your photos, you might have to do it every day for a few days to knock all of them off and make them stay off the plants.

I've never seen that many aphids on a plant before. When I first saw the photo, I was asking myself why the stems were yellow-orange, and then I realized the color was coming from the aphids. I assume those are the oleander aphids known to infest butterfly weed.

It is such a tricky thing to try to control pests on butterfly plants without harming any monarch eggs or larvae. If you could check the plants first up close and know for sure that there's no Monarch eggs or cats on the plants, you could spray the plants, particularly the aphid infested parts, with insecticidal soap. Then I'd wait 30 minutes or an hour and then wash off the soap so it wouldn't stick around and cause any problems either for the plant foliage or any Monarch cats that soon might be laid on the plants. If I have to use insecticidal soap for something, I spray it in the evening when the sun is low in the west, then wait a little while to let it work, and then hose it off the plants. Soap plus our intense summer heat and sunlight can be a bad combination, which is why I don't spray it during the day when the plants are exposed to sunlight.

Normally I'd say just to wait for the beneficial insects to show up, but in this case, maybe they are doing you a favor by not showing up. I'm fairly sure that my favorite garden helpers, the lady bugs, can and do prey upon butterfly eggs.

Spraying the plants with neem oil could be a drastic last resort, but I wouldn't do it until I'd checked all the plants and made sure no Monarch cats or larvae were on the plants.

I've had all kinds of insects all over the dill, parsley and fennel I planted for the swallowtails, and I've just hit them with the hose when there's no cats on the plants, and ignored the pests and let them be during times when the plants have had the beautiful swallowtail cats on them.

Dawn, I thought that was probably my options. Thanks. I will try the water stream tomorrow. Well, I will if i can pry my sprinkler head off my hose :)

The odd thing is that is the only plant they are infesting. I have a. tuberosa right next to it and they have completely ignored it so far. Of course Ice Ballet is much juicier, so maybe that is the draw :)

I haven't seen any monarchs lately, I'd be surprised if I had any eggs. I haven't seen any bst cats lately either.

I tried to think of some other way so that you wouldn't be discouraging monarchs from laying eggs, but there's not many organic options for aphids beyond spraying the off with water, soaping them or squishing them. (I am not a squisher.)

Do you have another Ice Ballet that is not infested? If so, then there is something stressing the aphid-covered one and pests always seem drawn to the most stressed plants. If that is your only Ice Ballet, I guess all we can do is assume they like it because it is juicier.

I've had lots of BSTs and their cats, but then, I always do. I think they flock here for the henbit I mow around in late winter/early spring since they love it so, and then they never leave. I've had monarchs for many weeks, but not so much in the last couple of weeks as I was seeing prior to that. I even had old faded ones in the garden and nectaring in the pastures back in spring---probably in the May timeframe. The only butterfly I've had laying eggs lately is the stupid bordered patch whose cats devour the foliage of sunflowers. I tried to trick them by not planting sunflowers in the garden, though we have native sunflowers growing beside the greenhouse, potting shed and garage, all of which are a couple hundred feet from the garden. So, are the bordered patch cats on all those dozens and dozens of native sunflowers? Nope. They're in the garden totally devouring the foliage of the native clasping coneflowers and my Cheyenne Spirit echinaceas I raised from seed. I love butterflies, but those bordered patch cats try my patience every year.

For a while, the BST cats were eating dill so rapidly that I thought they'd completely strip the plants and we'd lose the dill early, but the dill bounced back and put out lots of new foliage, so we still have lots and lots of dill plants. All of the dill plants now are flowering, and the foliage is being totally devoured, but not by the BST cats for whom it was grown. That would be too simple. It is being devouring by the grasshoppers.

I had those yellow aphids on my tropical milkweed last year. I had just as many as you do. I don't get aphids on my other kinds of milkweed.

While reading this morning I ran across some information that may be useful and that I will keep in mind. I'll include the link below.

"Discouraging early season aphids is helped by controlling the nitrogen your plants are getting. Using soluble nitrogen fertilizer early in the growing stages (often just when you want to use it). Aphids are attracted by high levels of nitrogen in plants. ThatâÂÂs why you might find plants youâÂÂve just pruned attacked. The aphids will seek out the high-nitrogen new growth that comes of pruning. Instead of highly soluble nitrogen fertilizers, including manures and fish emulsions, use something thatâÂÂs slow-released. When fertilizing roses, peonies or other flowers, use a formula thatâÂÂs higher in phosphorus than nitrogen. Keep pruning to a minimum if youâÂÂre having aphid trouble." 2014 Planet Natural by E. Vinje; Organic Control of Aphids

Thanks for that info!

I have never seen a milkweed that didn't attract them, even the antelope horns except they are so low to the ground you don't notice them. Those wild vine type milkweeds that grow like pests everywhere are always covered in aphids. Lady Bugs and baby lacewings are your best ally and they can clean a plant pretty fast. I ignore them and let nature take its course since its food for predatory insects. Lady bugs gotta eat too.

I thought mine were pretty they were very bright. I tried washing them off with the hose but they kept coming back.

I smooshed ...with gloves on :)....thank you Sharon for that good idea....and then washed down the plant with a water spray. I will check it tomorrow and see if it did any good. I didn't get them all by any means....just made a dent.