I appreciate all this great information. I now understand why two of my astilbes have not come back after they missed their waterings (due to a poorly working sprinker head, which is now repaired). The leaves dried up and although the base and stems are green, they are basically bald. I also live in Northern Nevada where there is zilch in humidity, and summers can get hot around late July and August. Although they are planted in a mostly shaded area, I think mulching will help. I will also add moisture retainers to the soil as well. I love astilbe,so I will give my plants every chance to do well.

I did sow heavy they have such tiny seeds. I had some from a trade and some I collected from my sis in laws. I started them out in a 44oz cup(my favorite method) Later as they got bigger I put them into a milk jug and let them grow there till I separated them and put them into the ground. I'll have to look through my old pics and see if I can find some for you. Once mine got about four inches tall and were planted out they seem hardy. One got broken and all the visible leaves died but after a week or two I noticed new growth there and it's still chugging along. The small ones that weren't as big I potted up into individual cups and waited to plant out. Now they are all in my garden.

I planted several varieties of astilbes for the first time when I lived in MD which is also zone 7 (as I still like to think I'm in here in TX). However, THAT zone 7 was a completely different climate than I currently have. We definitely did not have the continuing intense heat one gets in TX, even in Houston. The astilbes did well for me - in Maryland - blooming in the first season they were planted and thriving throughout the growing season. They overwintered just fine and bloomed again the next season (then we moved). They were shaded in the summer under a high canopy of the edge of a forest; a true woodland environment. They received dappled shade in the spring before the trees totally leafed out. The ground was low spot where runoff accumulated so it stayed evenly moist, but not flooded. I did find that I wanted them to bloom longer. From seeing the first beginnings of blooms to them becoming dried took probably less than a month. I think I may have needed to mass them more, as the blooms didn't make the kind of big impact I was looking for. They were nice when you walked close by but not that noticeable from a distance...and our house was maybe 80' away. If you have a moist area that stays shaded in summer, they might survive in that cooler space.

I have had a problem for a few years now. In my garden, there's a rock garden which was built before we came to this house. It's very authentic. Anyway, there are three levels and not much soil in it (due to some large rocks) and most importantly, a big pine tree on the top. So it's quite a shady area down under. My plan used to be planting astilbe and hostas under the pine tree. They grew poorly and never took off. It's actually a dry shade, so they suffered a lot. Their leaves turned brown in summer despite watering, there's been five years and none of them grew. There's been much root competition and probably very little soil. There is a lonicera brownii growing by the wall and it just hasn't grown much in more than 5 years! I have some spring bulbs planted too - narcissus, eranthis, corydalis solida, scilla, convallaria, crocuses, chionodoxa, puschkinia, brodiaea and galanthus. There are also some cyclamen, anemone lipsiensis, anemone nemorosa 'Royal Blue' and hepatica. On the lover levels, there are campanulas (portenschlagiana, poscharskyana, pulloides G.F. Wilson, cochleariifolia, cochleariifolia blaue taube), which I rely on mostly. Then there are some erodiums (Bishops Pink, Bishops White), two geranium cinereum (the most slow growing of them all), two geranium Jolly Jewel, sysirinchium, sedum kamtschaticum and cauticola. This year I planted solomons seal, corydalis Craigton Blue, lamprocapnos, doronicum, oxalis obtusa, hirta and adenophylla which went summer dormant. But the problem persists: under the pine tree only hostas, tiarella, pulmonaria and epimedium would grow. I know geranium macrorrhizum, heuchera, vinca, lamium and liriope would do it but they are planted somewhere else. I'm also growing corydalis lutea and corydalis ochroleuca from seed. So this year I bought some seeds of spigelia marilandica and germinated them successfully. There are many growing now and I really hope they'll get established. I also bought a hardy begonia (begonia grandis). Has anyone had any experience growing these two? Do they cope well with root competition? Do they tolerate drought? At least more than astilbe? It's been hard to give up on astilbes but they are just too fussy and sensitive for this situation.