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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.

 

 

 

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