En EspaŅol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
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 Compost and Mulch Questions

My newly planted Mountain Laurel isn\'t doing well.
March 13, 2009 - My mountain laurel was planted from a container in Dec. It is in part sun, clay soil, and its leaves are turning yellow. should I move it or will that kill it?
view the full question and answer

Sunny and shady lawns from Austin
April 28, 2012 - My front yard has a large bed surrounded by a mix of St. Augustine and Bermuda grass. Last summers heat killed off about 90% of the St. Augustine, which we would like to replace anyway to conserve re...
view the full question and answer

Live oak leaves turning yellow after planting in Houston
December 19, 2011 - We bought a 65 gallon live oak in early October, and have been watering fairly heavily three days a week. It seemed OK, then all of a sudden lots of the leaves are turning yellow. Is it getting too ...
view the full question and answer

Ground Arizona ash wood suitable for mulch?
April 23, 2015 - We cut down a 40 year old Arizona ash tree and had the stump ground into mulch. Can we use this mulch in our vegetable garden and flower beds
view the full question and answer

Flowers for sandy soil and sun in Wharton Co., TX
March 23, 2010 - I live in Wharton County. I am looking for flowers to plant in beds that have sandy soil and are well drained. The area receives sun all day until 5-6 in the afternoon. I would like to have flowers t...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center