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 strawberry tree dying in Mt. View CA
August 01, 2010 - My strawberry tree has brown leaves and is dying, what can I do?
view the full question and answer

Native shrubs to replace non-native boxwood in Parker County, TX
January 31, 2009 - I'm looking to replace some Japanese Boxwoods my wife planted years ago with some native plants, they run along the front of our house next to the foundation and porch about 60' in length. I prefer ...
view the full question and answer

Eliminating non-native grasses growiing in non-native alfalfa in Clint, TX
April 16, 2011 - I have six acres of alfalfa in Clint, Tx which was planted three years ago. After taking it to Jaime Iglesias PhD, CEA-Agriculture Texas Agrilife Extension El Paso County; he responded: Mr. Zuniga: ...
view the full question and answer

Failure to thrive of non-native Lamium maculatum
August 01, 2008 - Hello: Approximately 3 to 4 years ago I planted approximately 20 Lamium Beacon Silver plants in a shaded area of my yard, with limited sun. The first year they seemed very hearty and expanded. I ce...
view the full question and answer

Transplanting care of Mayten tree (Maytenus sp.)
November 06, 2007 - I planted a Mayten tree 2 years ago. It's about 8 feet tall. The trunk is about 1-1/2 or 2" in diameter. The earth around it sunk and now there is a "bowl" that fills with water in the rain. I...
view the full question and answer

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