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
Not Yet Rated

Tuesday - May 26, 2009

From: Philadelphia, PA
Region: Mid-Atlantic
Topic: Diseases and Disorders
Title: Problems with Blackeyed Susans in Philadelphia
Answered by: Barbara Medford

QUESTION:

For 8 years I successfully grew Black Eyed Susans in a fairly large area in my garden. For the last two years,almost immediately upon pushing through the ground they develop black spots and then appear to be eaten away. They continue to grow but the blooms are not vivid and the leaves are ugly. I have tried a variety of bug sprays - 3 in one,and copper dust. I just recently sprayed with Bayer Advanced-Insect control (3-in 1). I plan to spray weekly. Will that work?

ANSWER:

First, stop spraying pesticides. They are contaminating the soil and the air, and killing beneficial insects. Without knowing what the problem is, you can't hope to cure it with pesticides. Have you actually seen any insects? This sounds more like a soil problem, if they are showing symptoms as soon as they come up. Another strong possibility is mold. Although a number of different plants sometimes carry the common name "blackeyed susan," Rudbeckia hirta var. pulcherrima (blackeyed Susan) is native to Pennsylvania. It is a biennial, which will continue to reseed itself if it is in good conditions. It requires full sun, which we consider to be 6 hours or more a day of sun, and dry sandy soil. If conditions have changed in your garden, some other plants may be shading your flowers. You need to always clean up the debris in the garden on a regular basis, to help prevent mold or over-wintering insects from thrivng. Over-mulching, over-watering, over-shading, over-crowding all could be causing this problem. 

Read this Purdue University website on Septoria Leaf Spot of Rudbeckia.

University of Florida Cooperative Extension Service Rudbeckia hirta names several diseases and insects that may be causing the problem. 

You can't treat a disease without knowing what it is. Your spraying is very likely not only not helping, but may be encouraging the decline of your plants. 


Rudbeckia hirta var. pulcherrima

Rudbeckia hirta var. pulcherrima

Rudbeckia hirta var. pulcherrima

Rudbeckia hirta var. pulcherrima

 

 

More Diseases and Disorders Questions

How do you stop the bark from peeling off the tree in Amarillo?
May 07, 2012 - How do you stop the bark from peeling off the tree? I live in Amarillo, TX. If you can't stop the progression, how do you keep the tree alive?
view the full question and answer

Non-native blue potato bush in El Dorado Hills CA
June 12, 2010 - I have two blue potato bush topiary planted in my front porch in a very big planter. It's getting a full afternoon sun. I am wondering why they are losing their leaves??? Am I overwatering them??? Al...
view the full question and answer

Pruning oaks in August from Pflugerville TX
April 30, 2011 - Can I do minor pruning on my Lacey oak and bur oak in August if it is hot and dry? I'd like to prune one limb from each. The Lacey oak limb is about 2 inches in diameter, and the bur oak limb is ab...
view the full question and answer

Ailing Lacey oak in Austin
August 09, 2010 - I have a five-year-old lacey oak that is about 5 feet tall. Last last spring it became infected with oak phylloxera, which was initially misdiagnosed. I treated it with Neem oil several time but this ...
view the full question and answer

What is causing leaf drop on oak in Morgan Hill CA?
June 23, 2010 - Dear Mr Smarty Plants: We have a large, young Valley Oak (about 20 yrs) which is dropping leaves even now in early summer. I have a feeling that the problem might be an invasive weed that is flourishi...
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 | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center