Host an Event Volunteer Join Tickets

Support the plant database you love!

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
1 rating

Saturday - August 30, 2014

From: Livonia, MI
Region: Midwest
Topic: General Botany
Title: Is a height of 5 to 8 feet forOenothera biennis (Common evening primrose) normal?
Answered by: Nan Hampton

QUESTION:

I have identified a version of Evening Primrose Oenothera biennia L. In my yard, Livonia Michigan. These plants range in height from 5-8+ feet. Is this typical? The references I find indicates 3-5 feet.

ANSWER:

Our page for Oenothera biennis (Common evening-primrose) says 2-6 feet.  The USDA Plants Database Plant Guide gives the maximum height as 25 dm=8.2 feet.  Illinois Wildflowers says it grows to 7 feet tall.  Ohio Perennial & Biennial Weed Guide says the maximum is 6 feet.  University of Wisconsin Robert W. Freckmann Herbarium site says 2-6 feet and so does Minnesota Wildflowers. There are, then, several estimates for height, but I don't think yours are too far out of the ordinary.

There are several factors that can affect the maximum height of any plant.  One of these mentioned in the article, Seed weight effects on growth and reproduction in Oenothera biennis L. (by Katherine L. Gross and Marleen L. Kromer in the Bulletin of the Torrey Botanical Club, Vol. 113, no. 3, pp. 252-258) is that the soil type affects the height of the plant.  In a soil-sand mix the average height was 88.9 ±15.0 cm (appx. 3 feet 5 inches) and in greenhouse soil (without sand) it was 123.5 ± 4.0 cm. (appx. 4 feet 2 inches). The soil-sand mix was 50:50 regular greenhouse soil:sand. (Incidentally, the seed weight was not shown to have an effect on maximum growth.)  Many species that prefer growing in full sunlight react to heavy shade by becoming tall and, often, spindly.  Also, there could possibly be genetic variation that would account for the excess height of your evening primroses.

 

More General Botany Questions

Plant Groups
September 22, 2009 - What are ways to group plants?
view the full question and answer

Herbarium locations for Bifora americana
May 12, 2007 - Dr Hampton: I am trying to find specific locations of populations of Bifora americana (prairie bishop). Apparently, many collections of this species have been made in the Dallas-Ft Worth area as we...
view the full question and answer

Which one is huajillo and which one is guajillo?
November 19, 2013 - Recently I attended a field trip to the Leonard Garden at the Kleberg Institute in Kingsville. I took a picture of a tree that was referred to as Tenaza or huajillo. Later I took another photo of a ...
view the full question and answer

Is Common Milkweed a Succulent?
March 31, 2015 - Is the common milkweed (butterfly plant) classified as a succulent?
view the full question and answer

Mountain laurel with fasciation
July 24, 2014 - My Texas Mountain Laurel bush has developed several "crested branches." What causes this, is it harmful & how do I get rid of them??? Thank you!
view the full question and answer

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