I have never actually grown them, but was also considering adding them to my garden.

Everything that I have read indicates that they require a moist area. I have seem one variety that is more tolerant of dryer conditions, but I have only seen it in one place and at this moment I can't remember where.

My garden is under a crabapple tree and is not moist, so I haven't tried them.

Kristina, did you read the posting about someone being disappointed in astilbes? It has some information about people who either haven't had luck or just don't like astilbes. I had trouble growing them at my last house, but they were in a fairly sunny location and the soil would dry out occasionally. The flowers would sometimes dry up before they completely bloomed. The ones I've planted at this house are in shady locations and are mulched with chopped leaves. The soil is topsoil, peat, and compost mixed together with sand underneath. The area is not wet, but it gets watered regularly if it hasn't rained. They grow really well in those conditions, but I have no idea how they'd do in clay. I'm guessing that they wouldn't do as well.

Before you invest in any old astilbes, learn about the variety you're buying. While they all like moisture, some need more moisture than others. Some look awful after they bloom; some don't.

For example, Hennie Grafland (I think that's how it's spelled) has a fairly undistinguished pale pink flower BUT the foliage is a beautiful thick dark green, even now when the plant is long done blooming. I have it interspersed with some Emerald & Gold euonymous and it makes a nice contrast.

Vision in Red has dense dark red blooms to die for, but it the foliage isn't anything to write home about. It's in front of my backyard astible bed, beause it's fairly short as well as late-blooming.

Astilbe is pretty hardy; one time, some workmen trampled all over my back astilbe bed (before it had bloomed) while replacing the window over it. Everything they trampled came back the next year.

Almost any plant is easy given the right conditions. With Astilbes as noted moisture is a prerequisite. I have lost some, but now the ones that are established are threatening to take over.

I've found that they do best with moist soil full of compost/humus, and indirect sun/part shade. I have some that I planted in a bed this spring that gets a bit too much sun, and their leaf tips burned. I wonder whether if I water that soil heavily, they'll tolerate the sun, or whether I'll just have to bite the bullet and move them.

Another, older group of plantings is in a spot that is always moist, has rich soil and gets just a couple hours of sun, then bright shade. They look great and come back well every year.

Easy, easy, easy to grow. When I first started gardening I stuck astilbes everywhere, none of them in the correct soil conditions. That was 8 to 10 years ago, and they still come up and bloom every year and their foliage always looks good. Last year I actually planted some in moist semi-shade and they were spectacular this year. Some astilbes don't tolerate heat and humidity well, so buy from a local nursery that specializes in perennials for your area. As long as you get astilbes for your climate, they are super-easy.

I picked up tons of seedling astilbe from a local nursery and popped them around the front shade garden. Soil is only moist depending on rainfall, mostly sand although I imagine it's ammended itself with all the leaf fall each year etc. and I try to ammend the area of each new plant put in. They get probably 4 hours of sun each day. 2 hours morning and 2 hours late afternoon/early evening and they are literally going crazy. I have one that I think is over 4 feet tall. A gorgeous Amethyst one with the rest filling and just looking amazing this year. I'm going to divide them in the fall (hopefully) or spring and sprinkle more around. I don't do anything special with them (I'm one of those common sense gardeners. If it grows it stays if not well then what can I say). I love my astilbe.
Cheri

"I have some that I planted in a bed this spring that gets a bit too much sun, and their leaf tips burned. I wonder whether if I water that soil heavily, they'll tolerate the sun, or whether I'll just have to bite the bullet and move them."

You may have to... I planted a few late in the season this year and the next day we had 105 degree heat [that's so wrong for us!] - poor little things shriveled right up. I yanked them dunked their roots in cool water and moved them to a shadier/wetter part of the garden... so now he's doing fine! Just little burnt leaf tips to remind me never to plant one in that spot again... ;)

Violet Sky,
I did dig them up and relocate them. Had to. They looked miserable, all burnt. They've been in a shadier and cooler place for a couple of weeks now and are perking up, but they won't look really good until next year.

In the spot where astilbes suffered, I put gaura (wandflower) and lady's mantle, both of which are just right for there.

Can you trim the spent flowers and achieve a second round of blooms?

Deckman -- Astilbes have a fairly long bloom season, but I'm not aware of any varieties that will put on a second show if cut back.

One important thing about Astilbes that I don't see mentioned above is that they are heavy feeders. I fertilize them early in the spring with regular fertilizer & them give them regular doses of fish emulsion or alfalfa tea throughout the rest of the growing season. They also benefit from being divided every few years. I always work in organic material (peat, compost, etc) when dividing/replanting.