The link below may be of some help. You can search by flower color. Here is a link that might be useful: Minnesota Wildflowers

I used to grow blackberry lilies in Georgia and they bloomed right through the summer we couldn't water at all. However, I've read that the seeds don't germinate. It spreads like iris, which it is, according to the site Ginny provided.

Hi, I live in the country and have a small homestead. While I was down by the road searching for my guineas's nest the other day, I found a Passion Flower - Maypop vine. It had three slightly wilted exotic looking purple and cream flowers on it, which is what caught my eye. The leaves smelled like gourd or squash leaves. Very stinky. It was growing up over a poison ivy thicket near a dry creek bank. The leaves are three-lobed, glossy and quite lovely in their own right, even without the flowers. The stems are brittle and break off easily. The soil is very sandy. It was growing on the east side of the road, in the grader ditch, facing west in tall grasses and weeds. The hill rises up sharply from the road with an eroded cut-bank against the ditch. There are many large native trees and lots of small trees, grasses and other plants, so it was well sheltered. It is the only one I have ever come across around here and I have done a good amount of hiking and exploring, searching for wildflowers. It must have been brought in by some kind of animal or bird. My thanks to the critter that ate the fruit and pooped out the seed that was carried by a flash flood that deposited the seed that grew into the vine! (Hehehe) It would be mowed down soon by brushhogs, so I 'rescued' it. I dug it up with ample amount of it's native soil. It is doing fine so far. I put it in a large container next to a dripping swamp cooler so it would stay damp and have access to water until I could plant it. This is day four and she still looks good. Now I am thinking - How can I duplicate these growing conditions, without the poison ivy and grasses and weeds? (hehehe) My yard has the same kind of sandy soil. This entire ridge is sandy loam with sandstone bedrock, and it is very dry. On top of that, we are in a severe drought. I have to constantly apply compost and liberal amounts of Leaf Mold (Mulch) and old hay to the sandy soil and then water, water, water almost year round. The sandy soil leaches out all the good nutrients when I water or it rains, year round as fast as I can dig it into my gardens. I have a New Dawn rose and a Don Juan climbing rose growing up on either end of a big trellis at the back of an enclosed carport-shop. I was thinking it could go in there amongst the roses and do just fine. Its feet would be in the shade and its head in the sun, and it could climb all it likes. The colors would be lovely together. Good drainage is not a problem in my yard. It would have shade from the late afternoon scorching sun and protection in the winter. It would be sheltered from damaging winds, both the drying, summer winds and winter's icy blue northerns. Probably need to run the drip hose on her feet until she gets her roots set and growing. That ought to do it, though, don't you think? Since I am a novice at growing these lovely vines, I am putting it to you guys for your advice. Thanks. ~ SweetAnnie4u

It looks like St. John's-wort aka Hypericum perforatum L. Here is a link that might be useful: http://search.aol.com/aol/imageDetails?s_it=imageDetails&q=yellow+mentzelia+oklahoma&img=http%3A%2F%2Fbotany.csdl.tamu.edu%2FFLORA%2Fdcs420%2Ffa02%2Ffa02084.jpg&v_t=nscpsearch&host=http%3A%2F%2Fbotany.csdl.tamu.edu%2FFLORA%2Fimaxxloa.htm&width=124&height=157&thumbUrl=http%3A%2F%2Ft0.gstatic.com%2Fimages%3Fq%3Dtbn%3AANd9GcRGUoAU-6AGhBIXXNptF1cuouBCSyRcthJhyFDyHDHpJmcsrGVbnsbiFADb%3Abotany.csdl.tamu.edu%2FFLORA%2Fdcs420%2Ffa02%2Ffa02084.jpg&b=image%3Fv_t%3Dnscpsearch%26page%3D3%26q%3Dyellow%2Bmentzelia%2Boklahoma%26s_it%3DimageResultsBack%26oreq%3Daf9f5dfb54294b7fa45b7ee13e7a846d%26oreq%3D51cd9061c3384ee8bf7e0694f39d25cd&imgHeight=403&imgWidth=319&imgTitle=Mentzelia+oligosperma+-+Native&imgSize=63170&hostName=botany.csdl.tamu.edu