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Monday - July 25, 2011

From: Mohnton, PA
Region: Mid-Atlantic
Topic: Pruning
Title: Cutting back perennials in PA
Answered by: Anne Bossart


Can you pinch back echinacea in the spring to produce a shorter plant? I have some that get too tall and fall over.


Yes you can, but not this year.

There are a number of late-summer/fall blooming perennials that can be cut back by half in late spring/early summer.  As a result, they will be shorter and sturdier (less likely to need staking or fall over).  They will also be bushier and more floriferous.

I have had a similar problem in one of my perennial beds and tried it this year on:

Aconitum delphiniifolium (Larkspur-leaf monkshood)

Monarda didyma (Scarlet beebalm)

Phlox paniculata (Fall phlox)

So far, so good ... the monarda is blooming on schedule at a shorter height than usual and the other two seem to be budding.  I am in zone 5 and did it late in May ... you will want to do it a little earlier than that.

Besides these three and your Echinacea purpurea (Eastern purple coneflower), you can also give the same treatment to:

Eupatoriadelphus maculatus (Joe-pye weed)

Physostegia virginiana (Fall obedient plant)

Symphyotrichum oblongifolium (Aromatic aster)

and the tall sedum varieties.


From the Image Gallery

Larkspurleaf monkshood
Aconitum delphiniifolium

Scarlet beebalm
Monarda didyma

Fall phlox
Phlox paniculata

Eastern purple coneflower
Echinacea purpurea

Joe-pye weed
Eupatoriadelphus maculatus

Fall obedient plant
Physostegia virginiana ssp. praemorsa

Aromatic aster
Symphyotrichum oblongifolium

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