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?

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
Not Yet Rated

Wednesday - November 13, 2013

From: Rockville, MD
Region: Mid-Atlantic
Topic: Diseases and Disorders, Seasonal Tasks, Wildflowers
Title: Cutting Back Perennials in the Fall?
Answered by: Anne Van Nest

QUESTION:

We have large beds of flowering native perennials that we planted around our house as part of a landscape conservation plan (various Joe-Pyes, goldenrods, turtlehead, blazing star, brown-eyed Susans). Fall is upon us in Montgomery County, MD, and we see lots of birds having a great time kicking around in the leaves from the trees that are littering the beds. In the past we've cleaned the beds out down to the mulch layer before winter, but I'm starting to wonder if this is best for the plants and animals. Do we have to clean out the tree leaves before winter to keep the plants healthy? Can we leave them, or will this promote too much disease?

ANSWER:

The only parts of the garden that really need to be cleaned up well (down to the mulch or even replace this too) are any area around a seriously diseased plant. While native plants are generally disease and pest free, some problems like powdery mildew on phlox, leaf spot on bugbane, or overwintering leafminer on gaillardia could be serious enough to harm the plants. In this case all the affected foliage should be removed so that the fungus spores or insect eggs and pupa do not overwinter.  For the rest of the garden, healthy woody perennials can often be left intact or pruned to 6 inches for the winter.  Any seeds or insects still on the plant will be welcome food for the wildlife and the uncut stems will help collect insulating snow around the plant and give it extra protection as well as mark where the plants are located next spring.
Any fleshy perennials though (like touch-me-nots) should be removed in the fall since they will turn into a mushy mess after the first frost.
Leonard Perry of The University of Vermont Extension has posted a good information sheet on Fall Perennial Care online.

 

From the Image Gallery


Spotted joe-pye weed
Eutrochium maculatum

Ohio goldenrod
Oligoneuron ohioense

Pink turtlehead
Chelone lyonii

Ontario blazing star
Liatris cylindracea

Black-eyed susan
Rudbeckia hirta

Fall phlox
Phlox paniculata

Indian blanket
Gaillardia pulchella

Jewelweed
Impatiens capensis

More Wildflowers Questions

Wildflowers blooming in northern Wisconsin in July from Iron River WI
March 28, 2010 - What wildflowers are in bloom late July in northern Wisconsin, in the Bayfield and Douglas counties?
view the full question and answer

Can you grow wildflowers on a Zoysia greenroof?
June 09, 2015 - I have a 700 square foot zoysia grass roof with irrigation on a pool cabana that I would like to sprinkle with wildflower seeds (bluebonnets, indian paintbrush etc) Is this possible? What is the best ...
view the full question and answer

New Jersey Native Plants for a Raised Bed
April 15, 2015 - I want to plant some native plants in a raised bed in New Jersey along side a stucco wall that gets direct sun and is very dry due to an overhang. Any suggestions?
view the full question and answer

How to Propagate Mexican Bush Sage in Marble Falls, Texas
September 14, 2010 - I need advice on when, how to separate Mexican bush sage. Ours is happy and HUGE but is now sprouting from the roots at the base. Since we've been so successful with this plant, we want to divide it...
view the full question and answer

Need information about broadcasting wildflower seeds in a pasture 70 miles east of Dallas, TX.
April 20, 2011 - We recently moved to upper east TX - 70 miles East of Dallas. I would like to broadcast wildflowers in our pasture. I'm assuming I'll need to wait until next fall, but not sure about that. Can you t...
view the full question and answer

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