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?

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
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

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

Promoting growth on non-native dipladinias (mandevillia) from Point Pleasant NJ
May 26, 2011 - My Dipladinias were almost dead when I bought them last year, but after a little TLC, they blossomed like CRAZY in pots outside. They stopped blooming in November (I brought them into the house in Se...
view the full question and answer

Care of Rio Grande Wild Petunia
July 17, 2007 - I have bought the Rio Grande Wild Petunia, Ruellia davisiorum. How should I look after it?
view the full question and answer

Houseplant identification
October 15, 2014 - Had a houseplant with leaves that were green on the top and purplish on the bottom. The leaves were velvety to the touch. Would like to know what it was.
view the full question and answer

Problems with non-native mimosa
August 29, 2008 - We have 2 large mimosa trees in front of our house that are close to 50 years old. They have not been cared for over the past 8 years (we did not live here). This year, I trimmed them, removed dead ...
view the full question and answer

Non-native pittisporum disease in Austin
August 09, 2009 - Did Barbara Medford of Round Rock, TX ever find out what was causing sections of her dwarf pittosporum to die out? I have seen this in many yards now.
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center