Native Plants

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

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

Friday - March 04, 2011

From: Llano, TX
Region: Southwest
Topic: Cacti and Succulents
Title: Freeze damage on Barrel Cactus in Llano TX
Answered by: Barbara Medford

QUESTION:

I believe my barrel cactus has freeze damage. The flesh turned yellow and is now turning dark. The base is still green. If I cut off the damaged top portion, leaving the green base, should it survive? This would take off 3/4 of the plant, leaving only about 3 inches above the soil. It is a single barrel, not branched.

ANSWER:

There are several plants with the common name "barrel cactus." Of these, Thelocactus setispinus (Miniature barrel cactus) is shown on its USDA Plant Profile as growing in Travis County, which is relatively close to Llano. Another is Ferocactus wislizeni (Candy barrelcactus), which grows in Texas but only in two isolated counties, one in very far West Texas. Both cacti are indicated to be hardy to USDA Hardiness Zones 9-11. Travis County is considered to be Zone 8a and Llano County appears to be the same, so your cactus may be slightly out of its hardiness zone.

On this Arizona Cooperative Extension article on problems for cacti, scroll down to Page 5 where freezing problems are discussed. We found no conclusive advice on what to do with the damaged area; we would suggest you wait it out, see if the plant begins to put on new growth. Then, you can cautiously (those are SHARP spines) trim off the area you consider damaged beyond repair.

From the Image Gallery

Miniature barrel cactus
Thelocactus setispinus

Candy barrel
Ferocactus wislizeni