En Español

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

Thursday - July 04, 2013

From: Magnolia, TX
Region: Southwest
Topic: Diseases and Disorders, Cacti and Succulents
Title: Century plant leaves yellowing from Magnolia TX
Answered by: Barbara Medford

QUESTION:

The leaves on my large Agave/Century plant are turning yellow. The bottom leaves, touching the ground are dying. Plant is 5.5" tall, 6" across & approx 10 yrs old. Recently we put red mulch around the plant. Could this be causing it stress?

ANSWER:

There are 10 plants with the common name "Century" plant native to North America, of which 7 are native to Texas. None are native, nor even very close to, Montgomery County, in southeastern Texas. All are members of the Agave genus and, since your plant may not only be not native to your area, it may even be a hybrid or native to Mexico, which means it is not in our Native Plant Database at all. Here are three of the Texas natives, with maps for each from the USDA Plant Profiles, showing in which counties they are native:

Agave univittata (Maguey mezortillo) (Map) native closest to Montgomery County, in Kennedy and Starr Counties on the far southern tip of Texas.

Agave havardiana (Havard's century plant) (Map) native to to Jeff Davis, Pecos and Brewster Counties, in the West Texas Big Bend areas

Agave parryi (Parry's agave) (Map) native to Culberson, Jeff Davis and Brewster Counties, also in Big Bend Area

We mention these locations because we suspect the problems with your agave, whichever one it is, are cultural. Agaves are basically tough desert plants, accustomed to enduring intense heat, full sun and weeks without rain. For instance, here are the growing conditions for Agave havardiana (Havard's century plant), from our webpage on this plant:

"Growing Conditions

Water Use: Low
Light Requirement: Sun
Soil Moisture: Dry
Soil Description: Dry, rocky soils."

We have driven through Magnolia on our way to The Woodlands many times, and our impression of that area is that it is heavily forested, probably with acidic soils from all the leaves and pine needles that have fallen over the centuries, with more shade and more rain than this plant likely needs or can tolerate. This is why we always recommend the use of plants native not only to North America but to the area in which they have evolved because they are already accustomed to the sun, climate and soils of their native area. However, because we can't prove anything we have said, we will look for some research on what could be causing the yellowing and drooping of leaves.

Please read this previous Mr. Smarty Plants question for more information and possible fixes for your plant.

 

From the Image Gallery


Maguey mezortillo
Agave univittata

Havard's century plant
Agave havardiana

Parry's agave
Agave parryi ssp. neomexicana

More Cacti and Succulents Questions

Night-Blooming Cereus not Blooming
September 04, 2014 - I have a plant called a night-blooming cereus, which during the warm season, is supposed to have blooms that come out at night and close up but don't fall off when morning approaches. But my cereus h...
view the full question and answer

Need help with yucca palm in New York City, NY.
November 10, 2011 - I have had my yucca palm plant for almost 10 years. The bark has started to peel off although leaves seem fine. The second smaller separate yucca plant has half its bark and trunk gone. I can't see a...
view the full question and answer

Bringing upright a leaning cholla cactus
August 29, 2013 - I have a 3 ft. tall Cylindropuntia bigelovii that fell over after recent rains. I righted it and supported it with garden stakes for about a month. I was afraid to pull too hard on the low...
view the full question and answer

Will the blooming stalk of my century plant eventually tip over? Yes
June 24, 2009 - I have a century plant in bloom. Will the stalk eventually tip over? Would appreciate any Internet references on the subject.
view the full question and answer

Bugs on yucca plant in New Jersey
August 06, 2008 - I noticed small bugs ALL OVER 4 established yucca plants all near each other. They may look like Halticotoma valida but I'm not positive. There is no brown on the leaves except for the large amount...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center