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
Not Yet Rated

Tuesday - May 15, 2007

From: Austin, TX
Region: Southwest
Topic: Cacti and Succulents
Title: Root depth of opuntia
Answered by: Nan Hampton

QUESTION:

What can you tell me about the depth of roots of the opuntia? Does it vary with different varieties or is there formula to estimate the depth according to the mature size or to the culture - garden soil - wet or dry - etc ?

ANSWER:

As far as Mr. Smarty Plants knows, there is no magic formula to determine the depth of the roots of Opuntia spp. In general, the Opuntia cactus have tap roots with extensive shallow lateral roots. The size of the tap root and the lateral root expanse has to be correlated, to some extent, with the plant's age and size; however, environmental factors, such as abundance of water, soil temperatures, and CO2 concentration, also have a large effect on tap root depth and lateral root extension. For instance, a study of certain Opuntia species naturalized in Africa has shown that water stress increases the length of the tap root and reduces the size of lateral roots. In Opuntia ficus-indica increasing soil temperatures and CO2 concentrations cause the lengthening of tap roots.

You can read more about cactus survival strategies.

 

 

More Cacti and Succulents Questions

Container plant in difficult sun exposure from Leander TX
June 06, 2014 - HELP!!!! I have a large Mexican terracotta pot on my front porch. This awkward area is facing westward, so receives the full dose of Texas sun after about 3 pm onward. Now here's the catch; my fr...
view the full question and answer

Eliminating prickly pear
March 24, 2007 - What is best practice for eliminating 100+ acres of dense prickly pear?
view the full question and answer

Natural fibers for lashing bamboo in weaving
May 07, 2008 - I live in Austin and am looking for plants I can use for weaving fibers, e.g. lashing bamboo for a small project. What plants and parts do you recommend? What resources do you recommend for informatio...
view the full question and answer

Native plants of Taos and Los Alamos NM from Houston
April 07, 2012 - Hi, Mr. Smarty Plants, can you recommend a guidebook for the native plants of the Taos/Los Alamos region? (I'm most interested in forbs.) I'll be headed there in May--is there anything I should es...
view the full question and answer

Century Plant woes
May 04, 2016 - My century plant was fine two weeks ago. Tonight I seen this. Not sure what is happening. It 9 years old. IMG_4716.JPG
view the full question and answer

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