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?


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
1 rating

Monday - July 06, 2009

From: Lake Ronkonkoma, NY
Region: Northeast
Topic: Compost and Mulch, Propagation, Transplants, Herbs/Forbs
Title: Dividing blackeyed susans in Lake Ronkoko NY
Answered by: Barbara Medford


How are you supposed to divide blackeyed susan's? And when is the best time to do this?


The only plant we found with the common name "Blackeyed Susan" native to New York is Rudbeckia hirta var. pulcherrima (blackeyed Susan). According to the information in our Native Plant Database, this is a biennial, which may perennialize if it's happy where it is. So, we're going to go on the assumption that your plants are happy, and suggest you divide them in early fall in your climate, preferably after the first cool nights, but when the soil is still warm. The plant will be going into dormancy then and won't be quite so subject to transplant shock. You can spend some time between now and then preparing their new home, possibly adding some compost and working it in to improve drainage and to help make trace nutrients in the soil more available to new roots. 

We found an excellent website by Fine Gardening, 10 Tips on Dividing Perennials, which gives you information in a much more organized form than we could. 

Rudbeckia hirta var. pulcherrima

Rudbeckia hirta var. pulcherrima

Rudbeckia hirta var. pulcherrima

Rudbeckia hirta var. pulcherrima




More Propagation Questions

Yucca sprouting shoots in Oxfordshire, England
July 11, 2010 - I have a 20ft outdoor yucca with four huge branches.It is 11 years old. For the first time it has sprouted two side shoots on one of the trunks. They are about 12 inches in length. What is the best wa...
view the full question and answer

When is it safe to mow wildflowers in Castroville, TX?
May 26, 2010 - Hi Mr. Smarty Plants, My yard in Castroville, TX sprouted many wildflowers early in April. By now the Blue Bonnets are seeded and gone. However, I still have a lot of Mexican Blankets. My husba...
view the full question and answer

Altering the flowering time of Phacelia tanacetifolia
September 08, 2008 - I have been using Phacelia tanacetifolia as a forage plant in a 1 acre and 6 acre enclosure to mass rear the Blue Orchard Bee,(BOB), Osmia lignaria for use as a managed pollinator of almonds in Califo...
view the full question and answer

How to propagate milkweed from root cuttings
June 08, 2009 - I am interested in propagating Asclepias speciosa (showy milkweed). Your info page for this species says it can be propagated via root cuttings. Does this mean I can lop off a chunk of the root/tuber ...
view the full question and answer

Reproduction of purple coneflower (Echinacea purpurea)
May 06, 2008 - What is the reproduction of a Purple Coneflower?
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.
© 2015 Lady Bird Johnson Wildflower Center