En Español

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

Thursday - November 18, 2010

From: Bellevue, WA
Region: Northwest
Topic: Pruning, Seasonal Tasks, Grasses or Grass-like
Title: Cutting Juncus effusus back from Bellevue WA
Answered by: Barbara Medford


I read your posts about Juncus effusus and just have one follow-up question. When is the best time to cut them back to the ground - before winter or early spring? I live in the Pacific NW. I recently divided a large juncus (apparently wasn't supposed to until spring.) If it should survive, when is the appropriate time of year to cut it down to ground level to promote new growth? Thank you for your time.


Juncus effusus (Common rush) is native to Washington State, but King County is one of those areas with incredibly complex USDA Hardiness Zones, in this case ranging from Zones 6a to 8a. This USDA Plant Profile does not show this particular juncus as growing in King County, in the central eastern portion of Washington. However, these USDA maps are often out of date, and we believe the plant should be hardy in your garden.

From Floridata, we found this site on Juncus effusus, which does, indeed, indicate that the plant should be divided in Spring. However, with its underground rhizomes, it would probably take a lot more than premature division to kill it. Because you live in a mild climate, it really is only necessary to cut it back when it become unattractive, usually in the winter.

From our Native Plant Image Gallery:

Juncus effusus

Juncus effusus



More Grasses or Grass-like Questions

Growing Indian Wild Rice
September 23, 2010 - Could you tell me who has the Canadian rights to wild indian rice grass. It is a drought tolerant grass used in flour production for gluten free products. thanks
view the full question and answer

Groundcover for Shade in Spicewood
September 16, 2015 - We live in Spicewood area in Austin, TX. Our front yard is yellow almost all summer, I was thinking of replacing lawn with a ground cover which can live on once a week sprinkler and no mowing. Also th...
view the full question and answer

Native Grasses for Quebec
August 21, 2014 - I saw an article in the Martha Stewart magazine on native grasses. I live in Canada in Rimouski, in the province of Quebec. I am wondering if native grasses would grow here in the region? Our hardine...
view the full question and answer

What is blooming in NJ in Late November?
November 27, 2015 - I am a beekeeper in Edison, NJ. My bees are still bringing pollen even this late in the season (Thanksgiving). What plants or trees are still blooming? The color of the pollen is a pale yellow.
view the full question and answer

Plants to stop erosion on creek side
July 05, 2011 - I need plants for a westside slope to a creek that will help with erosion, need fast growing and likes lots of sun. Thank you, Mr. Smarty Plants
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center