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

Non-native Chamaedorea cataractarum question from Somerset MA
February 12, 2010 - I have a Chamaedorea Cataractarum palm and I was wondering what a clumping palm is. From what part of the plant do the new fronds emerge? Was trying to look all over the web but can't find it. If you...
view the full question and answer

Native Species List for Ponca OK
June 24, 2011 - I planted daylilies in my Austin garden and did not do well. I moved these daylilies to my garden in Ponca City Oklahoma and have done outstanding relying only on mother nature's rain. My garden in ...
view the full question and answer

Disposal of non-native invasive clerodendron
August 15, 2007 - What do you do about clerodendron that is spreading like wildfire. A friend gave me one plant before I was acquainted with invasives!!
view the full question and answer

Jasminum polyanthum Deer Resistant and Native?
March 07, 2015 - Are Jasminum polyanthum deer resistant? They are selling these plants at Trader Joe's right now so I'm assuming it's native to our area. But the instructions don't say anything about deer.
view the full question and answer

Care for non-native Spathiphyllum from Floral Park, NY
December 03, 2010 - I have a medium to large size friendship lily indoor plant that was once magnificent when first purchased it. I lost plenty of lush green leaves to brown spots. The health has improved( I moved locat...
view the full question and answer

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