En EspaŅol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
rate this answer
Not Yet Rated

Thursday - October 01, 2009

From: Thornwood, NY
Region: Northeast
Topic: Container Gardens, Pruning, Seasonal Tasks, Herbs/Forbs
Title: Overwintering Cardinal Flower in Thornwood NY
Answered by: Barbara Medford


I have 6 Cardinal Flower plants in planters. They have mulch on top to keep them moist. Can they stay in the planters all winter? Do I cut the stalks before winter comes or leave as is?


Lobelia cardinalis (cardinalflower) is native to New York and to Westchester County, on the southeastern tip of New York. It is hardy from USDA Hardiness Zones 3 to 10; you are in Zone 6a, with minimum average annual temperatures of  -10 to -5 deg. F, so it would seem the answer to your question is yes. The only reservation we have is that the roots will be in planters instead of the earth. When roots are in the ground, the whole earth is insulating them from the cold. In a planter, they are insulated by the mulch on top of the soil, a few inches of potting soil, and whatever the planter is made of. If it is possible, it would be better if the containers were situated in front of a sunny wall, where the day's warmth from the sun would be re-radiated back out to the nearby plants. If that is not possible, we still think the roots of this plant will be all right, just do everything you can to protect them from freezing temperatures. 


From the Image Gallery

Cardinal flower
Lobelia cardinalis

Cardinal flower
Lobelia cardinalis

More Pruning Questions

Trimming of Flame acanthus from Bastrop TX
February 17, 2012 - My flame acanthus never lost leaves off the bottom tier of branches this winter. With the brief warm weather and rain we've had, the top and middle tier of branches have all re-leafed. It is very l...
view the full question and answer

Removal of pods when pruning Tecoma stans
May 10, 2013 - When pruning Tecoma stans for growth and shape control,should I cut off the pods?
view the full question and answer

Lilies not blooming from Austin
May 03, 2013 - Last December 8, you published a letter in the Statesman that I had written to you regarding Rain Lilies, Oxblood Lilies, and Copper Lilies. The were sprouting in my garage in a bag. You recommended...
view the full question and answer

When and how to prune lavender (Lavandula sp.)
March 20, 2009 - Dear Mr. Smarty Plants I have a Goodwin Creek Lavender plant that I planted last year. It did very well but my question is about pruining. It seems that there is some growth coming up now that it...
view the full question and answer

Winter pruning of lantana from Austin
February 12, 2013 - I live in north Austin. Due to our mild winter, my lantana has not died off this season as it usually does after a freeze - and so I have not cut it back yet this year which I typically do about right...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
© 2015 Lady Bird Johnson Wildflower Center