Rent Shop Volunteer Join

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

Friday - October 28, 2005

From: TULSA, OK
Region: Southwest
Topic: Non-Natives
Title: Hours of darkness for non-native poinsettia to bloom
Answered by: Joe Marcus and Nan Hampton

QUESTION:

I have a poinsettia from last Christmas still alive. I was told to get it so many hours of darkness. Do you know how many hours? When would be the best time to start displaying the plant again?

ANSWER:

The poinsettia (Euphorbia pulcherrima) is native to southern Mexico. They are "short-day" plants which means that flowering is in response to long nights. It varies among cultivars, but 16 hours of uninterrupted darkness per night for several weeks is sufficient to induce the flowering response in any poinsettia. Any light at all will delay or stop the flowering response. There are classic stories about automobile lights from nearby highways and even flashlights from night watchmen delaying flowering on greenhouse grown poinsettias. People commonly put their plants in a dark closet each night for a few weeks in the fall to induce flowering and the red bract development (they bring them out each day). It is a little late to get your plant to flower by Christmas, but you can still get it to turn red just the same. If you start now, it may be red in time for St. Valentines Day! You can read more about the care of poinsettias.
 

More Non-Natives Questions

Transplanting non-native bougainvillea in Florida
February 10, 2009 - Hi, My neighbor has two established bougainvillea that he is giving me..I just have to dig them up and not kill them..what is the best way to dig up and transplant them?
view the full question and answer

Removing St. Augustine, replacing with native plants
October 06, 2007 - Hello Mr. Smarty Plants, always excited to talk to the Green Guru himself. I've recently purchased a house in South Austin and am interested in establishing a small, 500+ sq ft, prairie grass and wi...
view the full question and answer

Top soil dressing for bermudagrass
February 25, 2009 - Need to apply top soil dressing to bermudagrass. Can you suggest any type? This area is heavy clay soil and need to even out the lawn as well as feed the grass.
view the full question and answer

Crows foot plant for Christmas wreaths from Millsboro DE
November 04, 2012 - I am looking for a plant called crows foot to make wreaths for Christmas. Where do I find this plant.
view the full question and answer

Non-native little leaf linden (Tilia cordata)
June 24, 2011 - What is the name of the little leaf linden that has no flowers or pods to shed?
view the full question and answer

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