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
Not Yet Rated

Thursday - July 30, 2009

From: St. Louis, MO
Region: Midwest
Topic: Pollinators, Compost and Mulch, Herbs/Forbs
Title: Failure of tall garden phlox buds to open in St. Louis MO
Answered by: Barbara Medford

QUESTION:

Why won't the buds of my tall garden phlox open? Plants are apparently healthy, no powdery mildew or visible insects, foliage looks great and buds are profuse but they don't open. I have two clumps in different areas, both get full sun. I gave one clump a high phosphorous bloom booster fertilizer but it didn't help. The bees love the closed buds all the same. This happened last year too.

ANSWER:

Tall Garden Phlox are hybrids of Phlox paniculata (fall phlox), which is native to Missouri.  However, hybridized plants can present a problem, as you don't know exactly what their parentage is, and what attributes of the original plant were edited out and what others were added in to gain more height, different colors, longer blooming time, etc. We found an excellent website, Tall Garden Phlox for Minnesota Gardens, from University of Minnosota  Extension. We realize you are not in Minnesota, but the principles should apply. Please read the whole article but some of the things you should probably give attention to are:

The amount of sun (you already said you had full sun).

The soil being well-drained yet retaining adequate moisture; this may require incorporating a generous amount of organic material (compost, etc.) before planting. Plant grows best when it's moist.

Good air circulation to prevent mold, and watering soil, not sprinkling from above, for same reason.

Light application of balanced fertilizer as new growth emerges each Spring, again just before plants begin to flower. Not too much nitrogen, and don't use lawn fertilizer, which is high nitrogen. The high nitrogen encourages leaf development (as in grass) at the expense of flowering. 

 

 

 

More Herbs/Forbs Questions

Looking for Irises for Coryell County, TX.
May 07, 2012 - I'm looking for a hearty plant for Coryell County, TX. My mother always referred to these plants as "flags." I assume it is a type of iris. I'm looking for the one that will survive in the Cent...
view the full question and answer

Plants resistant to white-tailed deer from Austin
April 01, 2013 - Could you tell me whether American Beautyberry and Blackfoot Daisy are usually eaten by our Austin white-tailed deer, or not? I get different answers in different publications. It would be great to ...
view the full question and answer

Growing Chile Pequin Indoors
December 09, 2015 - About a year ago I visited your page and as a result I planted 8 seeds in spring 2015 from a large Chile Pequin plant that came up wild in my Cedar Park home near Austin. The last harvest was late su...
view the full question and answer

Planting iris rhizomes in Wisconsin
October 10, 2008 - I live in central WI and was given some iris bulbs (think they are called Rhizomes) and have no idea how to go about planting them. I am very new to planting so step by step instructions with good de...
view the full question and answer

Planting instructions for horsetail
March 10, 2009 - Re: Equisetum hyemale L. Canuela, Horsetail, Scouring rush, Scouringrush horsetail I bought a 1-gal Equisetum hyemale for my seep/pond. In searching the web, I find conflicting planting instructions...
view the full question and answer

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