Another Astilbe question....

[MMathis]

I've tried researching this on the internet, but am getting slightly different answers, so I don't know if this is "zone specific," or what.

1. Do the leaves die back in the winter or do they stay green?
2. In either situation, are you supposed to cut them back?
3. And if you cut them back, when is the best time?

 

[Robert Cummings]

Hi, whatever zone you are in you need to treat astilbe as a Herbaceous perennial. Cut back dead or dying flower heads to a leaf joint or growing point as necessary, as and when the plant has finished flowering and the leaves are looking old and tired, completely cut the whole plant back to 2" inches above ground level, clear away all cuttings to compost heap and mulch around the cut back plant with well rotted compost or manure. In the spring your Astilbes will start to shoot and a handful of granular fertiliser should be gently forked around the plant to feed hungry young shoots. You can repeat this procedure until such time that the plant outgrows it's space and then you will be able to divide the root to replant the offcuts elsewhere or share with your fellow gardeners.

 

[Verdun]

Word for word how I do it too Robert.

 

[MMathis]

@Robert Cummings Thank you! I am in US zone 8b, though for some reason, my profile said 7b -- glad you mentioned that. I've changed it.

 

[Robert Cummings]

Glad to be able to help you can treat most herbaceous plants in the same way Rudbeckias Echinacaea Aster and many more Good luck and hope this knowledge gives you much pleasure.

 

[MMathis]

....as and when the plant has finished flowering and the leaves are looking old and tired, completely cut the whole plant back to 2" inches above ground level,

I thought of another question......maybe a picky one, but here goes....
Here, in the Southeastern US, we sometimes have very mild winters, and sometimes plants that are supposed to die back, well, don't. So, you are saying that it's totally OK to trim back the entire plant at some point? And since we do go through cycles (we can go through several dormant/growth periods during our winters...!), where plants can and will sprout prematurely, would it be less stressful for the plant to wait and cut it back closer to spring......or would that even matter!

@tbendl For you, as well, since you're considering astilbe in MS.

 

[Robert Cummings]

Hi again, Cut the old growth back when the flowers leaves and stem are looking tired, but make sure you leave a stem about 2 inches high from the ground, Astilbes like many other herbaceous plants will make new growth from the base in the fall or Autumn as we call it here in the UK, the new shoots will keep growing when the weather is mild but you must cut back the old as leaving it will eventually result in poor quality plants.

 

[Verdun]

In spring any remaining old woody stems can be snapped off to make way for the new growth but astilbes are really very tough, vigorous and easy plants. Their only real requirement is moisture at the roots. Feeding with a dried manure mulch will further ensure a fantastic display of foliage and flower.