Host an Event Volunteer Join Tickets

Support the plant database you love!

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
1 rating

Monday - July 25, 2011

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

QUESTION:

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

ANSWER:

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

Spotted joe-pye weed
Eutrochium maculatum

Obedient plant
Physostegia virginiana ssp. praemorsa

Aromatic aster
Symphyotrichum oblongifolium

More Pruning Questions

When is the best time to trim oak trees in Driftwood TX?
September 09, 2010 - When is the best time to trim oak trees?
view the full question and answer

Browning of leaf tops on Iris plants
April 22, 2008 - My Iris plants bloomed beautifully, now some of the leaves are turning brown from the top down, about half way. Is this normal? What can I do about it and should I cut off the brown leaves? Also, what...
view the full question and answer

Care for lantana in Katy TX
December 04, 2010 - Hello. I live in Katy TX and have a number of Lantana shrubs. How and when should they be cut back?
view the full question and answer

Removing Center Stem From Desert Spoon (Sotol) in Phoenix
March 11, 2016 - I have a desert spoon. I hate the center stem. Can I remove the center stem without hurting the rest of the plant? And what is the best way to remove it? I looked for this answer in your questions bu...
view the full question and answer

Live oak leaves not dropping from Austin
April 29, 2014 - We had a 65 gallon live oak planted last October. We watered it regularly and it was green all through the winter. In March the leaves started to turn brown but never dropped, as they should have. ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.