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

Monocarpic plants for Indiana
October 06, 2005 - We were in Hawaii this summer and became acquainted with the Silversword. This plant (according to what we were told) blooms only once in it's lifetime (of 50-70 years). Are you aware of any other pl...
view the full question and answer

Century plant dying after bloom
August 12, 2007 - My century plant is so tall that it is up to the top of the telephone pole top lines that carry our streets electric. I was wanting to know if you knew if I cut the stock off would it save the plant ...
view the full question and answer

Saving frozen yuccas from North Carolina
February 23, 2013 - I live in NC and have 2 potted yucca plants on my deck. Every year I have brought them in for the winter. This year, someone told us that we could leave them out all winter. They began to die in the c...
view the full question and answer

Can Joshua Tree yucca be grown in Denham Springs LA
December 31, 2011 - If planted in a patch of raised and well-drained soil and covered during heavy rains, would it be possible to grow a Joshua Tree yucca in eastern Louisiana?
view the full question and answer

Winter care of succulents from Bethlehem PA
September 09, 2012 - We live in the northeast and we used succulents on our deck this summer because nothing else would survive the intense heat. How can I save these beautiful plants through a cold winter? Thank you.
view the full question and answer

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