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
3 ratings

Monday - April 30, 2012

From: Austin, TX
Region: Southwest
Topic: Pruning, Herbs/Forbs
Title: Trimming of penstemon after bloooming from Austin
Answered by: Barbara Medford

QUESTION:

I planted a penstemon in my backyard last fall and it's doing great. Once the flowers have bloomed, do I cut the stalk back? It is about 2 ft tall and doesn't appear to be doing anything. I believe I have a ruellia humilis.

ANSWER:

When we searched on our Native Plant Database on the genus Penstemon, we found 120 species; we switched to penstemons native to Texas and still got 26. So, we went to the Wildflower Center Master Taxa List, which lists all the plants on the Wildflower Center grounds. We figured we're in Austin, you're in Austin, the plants must be pretty similar, at least. The only Penstemon listed as growing on the grounds is Penstemon cobaea (Wild foxglove), so you can follow the plant link and learn more about the plant.

The answer to your question is yes, you can cut back the bloom stalks after they finish blooming. It's tidier looking, and the new growth emerges from the roots in the Spring.

What we don't know is what the reference to Ruellia humilis (Fringeleaf wild petunia) is all about. That is a whole different genus. We will admit there are some similarities in the flowers. You might also follow that plant link and see if you can figure out which is which.

 

From the Image Gallery


Prairie penstemon
Penstemon cobaea

Prairie penstemon
Penstemon cobaea

Prairie penstemon
Penstemon cobaea

Prairie petunia
Ruellia humilis

Prairie petunia
Ruellia humilis

Prairie petunia
Ruellia humilis

More Herbs/Forbs Questions

Yellow-flowered Ipomopsis rubra - Standing Cypress
May 30, 2008 - We have several acres of we call native plant areas, maybe unmaintained areas or natural is a better description of these areas. As we were developing these areas we sown in several different wildflo...
view the full question and answer

Sources for Eustoma exaltatum (Texas bluebells)
October 01, 2015 - Could you list sources for seeds for eustoma (texas bluebells)?
view the full question and answer

Landscaping with native plants in Austin
October 06, 2005 - I'm expanding a flower bed in front of my house and would like to keep it all natives. 1) How do I find out what type of soil I should add? (I live near Hyde Park, Austin and haven't had a soil te...
view the full question and answer

Deceptively deciduous, Cedar sage in Austin Texas.
May 13, 2011 - Is Cedar sage deciduous or evergreen? Your database doesn't say. Thanks, and I always enjoy my visit to the Wildflower Center.
view the full question and answer

Landscaping around a pear tree in Tyler, TX.
September 22, 2010 - We have a large raised flower bed, approximately ten feet by ten feet, surrounding a mature flowering pear tree. Do you have any suggestions for landscaping with native plants in this bed?
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