Rent Shop Volunteer Join

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
1 rating

Friday - August 09, 2013

From: San Antonio, TX
Region: Southwest
Topic: Container Gardens, Planting, Herbs/Forbs
Title: Growing conditions for Giant Coneflower from San Antonio
Answered by: Barbara Medford

QUESTION:

Rudbeckia maxima is considered to be a perennial plant for the sun but I have had a difficult time maintaining it in a pot in full sun before attempting to plant. Do you feel that it will survive and thrive in the sun in the San Antonio area with temperatures reaching 105? Will it need deep soil and lots of water?

ANSWER:

Here are the growing conditions for Rudbeckia maxima (Giant coneflower) from our webpage on that plant:

"Growing Conditions

Water Use: High
Light Requirement: Sun , Part Shade
Soil Moisture: Moist
CaCO3 Tolerance: Low
Drought Tolerance: Low"

And

"Native Habitat: Found in moist open places. Forming beds in low ground, sandy or silty soils; east Texas west to East Cross Timbers. Seems pretty drought resistance despite its swampy origins."

From this, we are inferring a need for part shade (2 to 6 hours of sun a day) in such a hot summer, as well as lots of water. The problem for plants in pots in either extreme heat or cold is that a few inches of potting soil and the sides of a pot are not much insulation for the roots. Its native habitat appears to be low places and swampy soil, indicating some shade during the day. Also, the insulation of the earth around any roots is more valuable than any kind of pot material for the preservation of the roots. We would suggest you either move the pots to a shadier spot, or transplant the coneflowers into soil earlier in the season, before the heat becomes so intense.

 

From the Image Gallery


Giant coneflower
Rudbeckia maxima

Giant coneflower
Rudbeckia maxima

Giant coneflower
Rudbeckia maxima

More Herbs/Forbs Questions

Ground cover for shady area in north Texas
July 29, 2013 - I'm looking for a ground cover for a mostly shady area where St. Augustine won't grow. I don't want the ground cover to overtake my established St. Augustine in the rest of the yard. The area is un...
view the full question and answer

Plants for full-sun landscape
November 20, 2007 - I live in a very rocky area just outside of Fort Worth, TX. It's taken me all spring, summer & now I'm going into the fall, to landscape just 30 feet in front of my house. The front of the house get...
view the full question and answer

Damaged newly planted Gaura in Austin
April 16, 2010 - Hello yet again! This past Friday we attended the plant sale where we got lots of goodies to start a new bed. The plants were all planted on Sunday. All of them are doing fine, even beginning to...
view the full question and answer

Propagation of Asclepias tuberosa
June 18, 2012 - Re: Asclepias tuberosa, "butterfly weed" bush -- I have a bed in a mix of Shoal Creek well-drained caliche, soil, and some enrichment of mulch that gets almost full sun and low water. After 4 yrs a...
view the full question and answer

Plants for a pool fence in Ohio
October 28, 2010 - I live in Ohio and have a pool with a white vinyl fence. Each year I plant sunflowers around it, but they are so messy when the birds/bees find them. Previously I planted castor beans, however, they...
view the full question and answer

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