During the very hot weather earlier this summer I watered them a few times so they wouldn't dry out, but I stopped when they started to turn brown.

==>> its really hard.. in hindsight.. to determine when an injury occurs.. rather than when it 'shows up' ...

i find it significant.. that when you stopped watering.. they seemed to recover ... regardless of the fact that they browned about the same time ...

do you.. in any sense.. insert your finger.. and water when they need it.. or were you just hosing them down all the time.. perhaps drowning them in the process along with ambient rain ....

my GUESS ... would be some interruption the the roots ability to pump requisite water ... and your decision to ignore them ... saved them.. in time ...

i often say ... on various posts.. that peeps are on the verge of loving a plant to death ... perhaps you were too.. and saved it thru abject neglect [the latter being my preferred option. lol]

the garden is a mystery ... i am glad you have watched a mystery as such ...

ken

I had watered them occasionally when I was watering a struggling rhododendron my father gave me. For the rhododendron I checked the soil, but not for the Astilbes. I don't like to water since I'm always afraid of overwatering, plus I have to fill, refill, and lug around a watering can (rental complex, so no spigot, though some units do have them). The rhododendron is rather large and dried out easily during the hot weather, so many times I only watered that.

kato: I think you are right. They really wilted and then browned during the heatwave. This is the first time I planted Astilbes and I have never had a plant do this before. Now I just hope they survive the winter.

Kato is correct in saying astilbes will go dormant when not watered enough and leaf out again when ideal conditions return. In some cases, the plant may remain dormant until the next spring.

I have never experienced astilbe leafing out again after drying out. The rule here has always been: once brown- stays this way to the end of the season.

I am in the same zone you are and a bunch of my astilbes also turned completely brown in the heatwave we had this summer and are all sending out new leaves now. The few I had from last year didn't turn brown but the few I had planted this year all did so I am assuming it has to do with the heat and not having an adequate root system yet.

Well I feel much better knowing others have had this happen. I was happy to see them come back, but afraid there would be some permanent damage because of this. Honestly, I can't blame them for going dormant. Even I mostly stayed in my air conditioned room as much as possible during the heat wave. So glad its over, and hopefully we won't get another one again this summer.

I wish I would have discovered Astilbes years ago. I don't think the local greenhouse where I lived had any - they had mostly sun plants. It was a small business (couldn't even accept credit cards) and they had very healthy plants, but I live about an hour away now. The main plant I focused on trying to get was a hydrangea, and I was eventually given one...about 8 months before I knew I was moving. I transplanted it to my dad's house and hoped for the best. It is now gone. Dad said it must have died, except his girlfriend has a pond there now and she is the type to throw away things because they are/were mine (which is why I don't visit my dad more often). I've got a Nikko Blue now, but its so tiny it will be awhile before I see flowers (with my luck, it will probably be right before I move again). The Astilbes were the first plants I planted in my current garden. I think next spring I'll add a couple more.

We routinely cut back the astilbes after they brown out, and they almost always put out new growth.

I have had the same experience recently as most of you. My two year old astilbes got really leafy and bloomed quite nice. They are the variety "Deutschland" and they still have their leaves now and July is growing to a close.. The new ones I put in this year in different spots were happy and growing and without a blemish in the spring. Then the 90â¢F+ days started and all the new ones turned brown and the leaves "died" completely. I am confident that they are just dormant though. They seem to dislike the heat.
The new ones are Ostrich Plumes in a corner of the yard and "Red Sentinel" around a crepe myrtle tree. They will be back. Just gathering their strength.
Also, Just a fun fact regarding plants: Unless the foliage is diseased you want to leave the leaves that are turning brown on plants. They do a process called apoptosis where they break down the old cells and use the raw materials to build new things such as roots below the soil or new leaves. So leaves that aren't completely crunchy yet are usually being taken apart and the building blocks getting used elsewhere.

~ Happy Gardening ;)

So far this year we haven't had much heat and we've had plenty of rain, so my Astilbes look great. They only died back the first year (2 years ago) during the heat wave. I don't remember if we had a heat wave last year, but they didn't die back then. I wish the flowers lasted longer, but they are nice for that short period of time. My Visions in Red has an awesome color and makes my neighbor a bit jealous.

I had moved my Astilbes in the spring and under estimated how big they would grow, so next spring I will move them again. One is bigger than the other and growing over my new garden path. I haven't decided yet if I want to divide them -- they are still young and not too big yet. Plus I am running out of room for new plants because of my love for hydrangeas.

Mine did this during hot spells each year for the first two or three years I had them, but now that they are well established, they don't do it anymore (as long as I keep them watered).

My astilbes have great green leaves but the pink "flowers" are horrible and brown. They are watered daily and I am thinking it's too much water? Can I save them or should I rip them out and plant something else?. They get a little sunshine but I would say mostly shaded by the fence.

Sounds normal. The flowers don’t bloom all summer. They flower once then you can cut off the dead flowers and enjoy the foliage until next year.