Explore Plants

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
    
 

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 Pollinators Questions

Looking for a male Southern Wax Myrtle in Newport News, VA.
August 20, 2012 - We are looking to add more southern wax Myrtles to make a hedge row with them. We already have one in the ground that is a female. I have called around to see if anyone sells the male but i keep get...
view the full question and answer

Neighborhood association wanting wildflowers mowed from Grand Prairie TX
July 14, 2013 - For at least 15 years, I have been fostering growth of wildflowers in 60% of my 90x400' yard which include 150' utility trunkline easement in which I can plant no trees. This year, we had volunteer ...
view the full question and answer

Shrubby options for a bird lover in New Jersey
September 07, 2011 - Could you please recommend a native shrub to NJ that grows to about 3-4 feet, is very low maintenance, does well in afternoon sun and is also something the birds will like? Thank you.
view the full question and answer

Early, middle and late blooming flowers for pollinators in East Texas
July 05, 2010 - On our farm in northeast Texas we are participating in a Conservation Program through the NRCS. We have to plant 4 acres for pollinators--early blooming, middle blooming, and late blooming. I need t...
view the full question and answer

Plants for pollinators & honey bees in PA
March 12, 2012 - In the database section entitled "Value to Beneficial Insects" on the page for "Tilia americana L" (also known as the Bee Tree, or Linden Tree, American Basswood); the tree is identified as being ...
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.