En Español

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

Bees on non-native holly from Oakland TN
April 18, 2013 - I have bees all over my Nellie Stevens holly. Can I spray anything to alleviate this issue?
view the full question and answer

Non-native Cape Honeysuckle, Tecomaria capensis
March 13, 2006 - I am trying to find general information on the Cape Honeysuckle or "Tecomaria" bush/plant. Is is related to the actual Honeysuckle Plant? What is it's care, propogation, sun tolerance, water requ...
view the full question and answer

Survival of non-native windmill palm in Zone 6b
March 28, 2009 - Will a windmill palm survive a Zone 6b Michigan climate; if so would I have to wrap it up in burlap in wintertime?
view the full question and answer

Problems on mock orange plant in England
August 20, 2008 - I have a small mock orange plant that is about 3 years old. It is currently in a 12 inch plant pot in full sun. It bloomed beautifully this year but the leaves on both the new and old growth are start...
view the full question and answer

Problems with non-native Banana Shrub from Houston
May 01, 2014 - My 7' beloved Banana Shrub (magnolia) has white dots on top of the leaves and nasty black stuff covering the backside of the leaves. The plant is dropping leaves. What can I do to save it? I has bee...
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 | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center