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

Problems with Agave americana in Comfort TX
November 09, 2009 - We have lost a huge agave americana and are not able to find out what to do for our others. The one we lost was rotted or eaten (beetles?) at the base and the whole thing just fell over. We have a l...
view the full question and answer

Will a cut back yucca grow back in Lockbourne OH?
October 28, 2009 - I live in Ohio and recently I cut back all my plants to prepare for winter. I am wondering if my Yuccas will grow back. I cut them to ground level so only a little bit of the leaf is showing. I was...
view the full question and answer

Topmost leaves on yucca are brown
June 08, 2009 - I live in the Lansing, Michigan area, in the lower peninsula and have a couple yuccas whose topmost leaves are brown emerging from winter. Do I prune those, or has the plant died? Thank you.
view the full question and answer

Sun loving plants for flower bed by the pool in Weatherford Texas
October 03, 2011 - We have a 40' long x 2 1/2' wide flowerbed along our pool. It is in full sun with the pool deck across the front and a 6' privacy fence across back. Also, the level of the bed is 18" below the l...
view the full question and answer

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