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
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

QUESTION:

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?

ANSWER:

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 Seasonal Tasks Questions

Native plants for Summer Planting in Vernal UT
May 24, 2011 - What are the native plants that I could plant this summer in Vernal, Utah
view the full question and answer

High mowing equipment for Llano TX
November 03, 2012 - We're trying to follow your wildflower meadow recommendation "if your meadow has tall, warm-season native grasses, wait until late summer or early fall to mow, allowing them to elongate, flower, and...
view the full question and answer

Trimming native salvias in January
January 17, 2008 - I have heard you can trim Hot Lips, Raspberry and other salvias back severely in January, to about six inches from the ground. Is this correct?
view the full question and answer

Deadheading Mexican hat to produce more blooms in Austin
July 05, 2010 - I have several Mexican hat (rudbeckia) plants growing wild in my yard. Would deadheading now give them a second flush of bloom in fall?
view the full question and answer

Pruning cherry laurel in January in Austin
January 07, 2011 - Do trust I checked Q&A first. Can Cherry Laurel shrubs be pruned earlier than late winter in Austin? I foolishly planted 12 native Cherry Laurel standards on our suburban property line 5 years ago. I ...
view the full question and answer

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