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
1 rating

Sunday - July 20, 2008

From: Houston, TX
Region: Southwest
Topic: Container Gardens
Title: Failure of potted verbena to bloom
Answered by: Barbara Medford

QUESTION:

I have a trailing purple verbena that won't bloom. It is in a container, not in the ground, and gets lots of sun. What is the problem?

ANSWER:

In our Native Plant Database, there are 36 species with the name "verbena" in the name of the plant, most members of the genus Glandularia. Probably the most-used native verbena is Glandularia bipinnatifida (Dakota mock vervain). We are pretty sure that what you have is some sort of a hybrid, with different colors, as that is what is usually available in commercial nurseries. Since we don't know, and you were probably not given any indication, what hybrid this would be, we can only deal with your question on a general basis. This website from GardenGuides.com Verbena can give you some more care information, regardless of the species. In cooler climates, verbena are considered annuals, but in Houston, you should be able to get it to perennialize. You said it was in a container, so you need to make sure the container drains very well. The verbena needs moist soil until it is pretty well-established, but cannot tolerate soil that does not drain well, and may develop disease because of the poor drainage. The native verbena mentioned above blooms from March to October. Although our webpage on the verbena says it needs part shade, which we define as 2-6 hours of sun a day, other websites say that verbena needs full sun, up to 8 to 10 hours a day of sun. A plant that needs lots of sun to bloom is not going to do well in a more shaded location. If blooms seem to slow during the summer, you might trim the whole plant back by about 1/4, and hopefully it will recover its vigor and bloom again. Dedheading is important on this plant but, again, just trimming across the top to take off spent blooms should suffice, instead of snipping off each individual blossom. If your plant has lush foliage and no flowers, we suspect the plant food you are giving it is heavy on nitrogen, which promotes green leaves. Switch to one that has a higher phosphorus content, the number in the middle of fertilizer designations, and see if that will inspire your plant to bloom.

 

From the Image Gallery


Prairie verbena
Glandularia bipinnatifida

More Container Gardens Questions

Winter plants for windowbox in Piedmont SC
October 26, 2012 - What kind of outdoor window box spruss can grow in upstate South Carolina in the winter months?
view the full question and answer

Native plants for small pots in sun in Austin
January 24, 2011 - Hello Mr. Smarty Plants! We are renting our house, so while we have a yard, the landlord would prefer us to only add plants to his landscaping in pots. I have filled some large ones, but have been una...
view the full question and answer

Shrub that will grow outside in Zone 5 from Millbrook NY
April 21, 2012 - Is there any shrub, tree or other sort of plant that will grow well in zone 5 in a very large container outdoors?
view the full question and answer

Native plant for container on deck in Oak Grove VA
April 05, 2011 - What VA native plant can I grow in a container on my deck that will block the view from the neighbor's deck? I am thinking columnar. This is in full sun and gets hot winds off of a bay. The plant ...
view the full question and answer

Return of empty Plant Sale pots from Austin
April 20, 2010 - Would the WFC want the empty plant containers back? I live near the center and could drop off quite a few containers, along with plastic tags. Let me know where, if so.
view the full question and answer

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