Host an Event Volunteer Join Tickets

Support the plant database you love!

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

Friday - April 04, 2014

From: Leander, TX
Region: Southwest
Topic: General Botany, Drought Tolerant
Title: Water-saving strategies of drought-tolerant plants
Answered by: Joe Marcus

QUESTION:

Although "drought tolerant" plants are fairly well documented, it's clear that many different strategies are responsible, such as a huge root system (like Mesquite). I'm interested in learning the characteristics that allow plants other than succulents to USE LESS water to thrive. I believe that small or waxy leaves are such characteristics. Are there other qualities that might help us decide which natives to plant, so as to reduce our water consumption?

ANSWER:

It is true that plants native to arid lands employ a variety of methods to reduce the amount of water used, including deeply-growing roots, fleshy water-storage organs (roots, bulbs, stems, leaves, etc.), reduced leaves and waxy epidermal coatings.  Another strategy for water conservation used by many plant species native to areas of low rainfall is CAM photosynthesis.  

Arid country plants do not conserve water so much by sequestering less water in their tissues -- to the contrary many of them actually store more water than species native to areas of higher rainfall.  Rather, these species reduce the amount of groundwater removed from the soil and passed to the atmosphere through the process of evapotranspiration.  CAM plants accomplish this by enabling their stomata to remain closed during the day when evapotranspiration rates are higher and carry out their photosythetic process at night when evapotranspiration rates are lower.

So the CAM process itself is not so important to water-use reduction as what the process allows those species employing it to do.  That is, it allows them to carry out photosynthesis at night when evapotranspiration is reduced.  With less than 10% of the earth's plant species employing the CAM carbon fixation process, those plants that do, use less water than those using the more typical C3 and C4 carbon fixation pathways.

Whatever water-saving strategies are employed, the important fact is that plants native to arid lands are well-adapted to their environment and the reduced availability of water there.  For that reason, the method of water savings is somewhat moot.  Native plants' adaptation to low water availability is in large part why we strongly encourage their use in landscapes within their native ranges.

 

More Drought Tolerant Questions

Hedge in Desert Full Sun
March 25, 2012 - We want a short hedge, 2-3 ft tall, small leaves that fill in to full looking hedge. It is in Phoenix Arizona area and gets full sun all afternoon
view the full question and answer

Winter- and drought-resistant plant for North Central Texas
April 11, 2012 - I would like to know is there a good winter and drought resistant flowering bush for my area. I would like something with bigger flowers like azaleas or roses maybe bigger, that will not grow anymore...
view the full question and answer

Erosion tolerant plants for shade from Kerrville TX
August 06, 2013 - We have just cleared a lot of cedar out of a small draw and would like to know the best groundcovers, shrubs, etc. to plant to hold the soil. Deep shade most of the day.
view the full question and answer

Drought-tolerant trees for planters in San Diego
August 09, 2012 - We need some ideas for a drought tolerant tree that will provide shade (4 foot raised planters in sunny location) not get too big when mature, and not too messy. San Diego
view the full question and answer

Plants for a hillside in WI
February 18, 2012 - I live in Wisconsin and am currently doing a research project on plant variation on the north and south sides of a hill. I was wondering you could suggest any books to me that would address this issue...
view the full question and answer

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