Butterfly Weed, Asclepias tuberosa
, gets its name from the fact that butterflies like it... and it's a weed? Okay this is why common names suck; labels at any garden center will have you think all plants attract butterflies, and calling something a weed is subjective. In the right setting butterflies will flock to this plant but so far we're having an off year for butterflies.
This particular species is most often found with orange flowers, but there's also a yellow form and one with deeper red vanes. Although I grow both yellow and orange forms, this one pictured above is a seedling that's come up on it's own.
This is a brilliant care free plant for dry sunny places and once established they won't need watering at all. In fact it's been reported this plant will stay lush and green even after grasses have gone brown and dormant around it.
The red vane doesn't always occur on the flowers, but I've seen some patches that had more red to them than orange. This doesn't seem to be common at all and I wish I had some to show what I'm talking about.