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

Monday - June 22, 2009

From: Austin, TX
Region: Southwest
Topic: Watering, Cacti and Succulents
Title: Why are the leaves of my century plants yellowing?
Answered by: Jimmy Mills

QUESTION:

I am taking care of the Agaves (century plants) for my condo community here in Austin. They are planted in 18" or 20" pots. A couple of the plants have leaves that are yellowing around the bottom. At first I thought it might be under watering - I soak them once every other week for about two minutes. Now I'm starting to think it might be over watering. They are all lined up facing West and the ones on the north end of the line up are the ones experiencing the most yellowing. Any ideas?

ANSWER:

The term Century Plant is applied to eight different Agaves in our NPIN Database.  Since Agaves are adapted to surviving in dry environments, over watering is probably more of a threat in your case than under watering.

While some yellowing of lower foliage is normal in Agaves, this could be a case of salt burn which is a result of build up of soluble salts in the soil. Another sign of salt build up is the accumulation of a white residue on the outside of clay pots or on the rim of plastic pots and on the surface of the soil. This condition can be taken care of with leaching which in effect flushes the excess minerals out of the pot.

To accomplish this, give the plants a normal watering and wait  for thirty minutes to an hour. Then pour an amount of water that is four to five time the volume of of the soil in the pot, allowing it to drain through the hole in the pot. Discard the drained water, and wash out the saucer before returning the pot to it.

I'm including a link to an article on watering guidelines from  Colorado State University Cooperative Extension, and a link that describes the leaching process.

 

 

 

More Watering Questions

Water use rate calculations from Toronto ON
December 16, 2012 - Can the high medium and low water use categories be quantified into a rate, say volume of water required by square foot of planted area? How are the water use categories established?
view the full question and answer

Failure to thrive of closet plant
August 13, 2008 - I have a closet plant that is old and was doing fine and then started having droopy leaves. It needed to be in a larger pot so I transplanted into a larger pot with new potting soil. It continues to...
view the full question and answer

Watering oaks during drought in Austin
July 29, 2009 - Should we be watering our live oaks and Spanish oaks during this drought? How often and how much?
view the full question and answer

Transplanting a non-native rose from Akron OH
August 30, 2012 - Can I transplant a rose plant that I have in sunny area to an area that will be partially shady?
view the full question and answer

Wind and erosion tolerant plants from Austin
August 05, 2013 - I recently cleared a fire break by removing cedar from around my home in West Austin. I'd like to plant the exposed NW facing slope with native shrubs and trees. Looking for selections that can wit...
view the full question and answer

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