I'm growing it and it is doing very well. I've seen it in gardens doing so-so. It really does thrive in hot and dry - mine is on a west facing steep hillside that is planted for mostly no water. I did have it elsewhere where it didn't do well tho. So too wet is not right and extremely dry sandy was not good either. Mine has just started blooming now but blooms all the way til November. It'll disappear for the winter but with good drainage will make it thru just fine and return. Its a bit of a creeper but I like it alot.

Not very difficult or rare. Try it.

What are the lowest growing forms and cultivars? I have a very vigorous one blooming now that grows about 18" tall but I prefer a shorter form for the base of a planter at the edge of patio.

'Mattole Select' stays quite low. Very nice silver foliage, too. 'Solidarity Pink' is low, too.