Agave edema strikes again

A couple of weeks ago, I bought an Agave attenuata ‘Blue Fantastic’ at the UC Davis Arboretum Teaching Nursery for the newly revamped front door bed:

Agave attenuata ‘Blue Fantastic’ at UC Davis Arboretum Teaching Nursery

Before heading home, I made a brief stop at Trader Joe’s, no more than 20 minutes. While I was in the store, the agave was sitting in the car, with the windows slightly cracked. Imagine my frustration and annoyance when, just a few hours later, I discovered that several leaves were starting to show large brown spots:

The next day, after I planted it in the ground

Here’s a closer look:

And a week later:

20 minutes in a closed car on a reasonably warm morning, that’s all it took. Fortunately, the damage is cosmetic, but still, it’ll take my agave until next summer to shed the blistered leaves.

If you’ve ever transported agaves in a closed car on a warm day, you might have experienced this yourself. Some species seem to be more prone to this, especially those with thinner leaves. This phenomenon is well-known to growers who transport agaves and other succulents in closed delivery trucks or trailers. In the Spring 1997 issue of Santa Barbara Garden News, pest control advisor Robert Muraoka called it “oedema.” I don’t know if he was the first to use this term, but that’s what it’s referred to now: agave edema.

In a 2016 Facebook thread started by Loree danger garden Bohl on this very topic, agave expert Greg Starr said: “I attribute the damage to the process of respiration being interrupted very suddenly, causing the stomates to shut rapidly and not allowing gas exchange to slow normally, thereby causing the surrounding cells to burst from a ‘gas overload’. I think [the cause is] primarily a light-dark change frequently in conjunction with a change in temperature. I have noticed this happen more when transporting plants from a cooler to hotter location, but that is not consistent.” (To see more responses to this Facebook thread, read Loree’s original blog post.)

It’s important to note that this is not caused by a pathogen, but simply by a disruption to normal physiological processes. There’s no sure-fire way to prevent this, short of not transporting plants on a hot day. According to an article on the San Marcos Growers website, “it seems that plants transported with good air circulation fare much better than those in closed stagnant areas.”

In my case, I should have known better. After all, this isn’t my first experience with agave edema (I wrote about it in this April 2024 post). I should have taken my Agave attenuata out of the car when I got to Trader Joe’s and left it in the shade next to the car. I doubt anybody would have stolen it.

© Gerhard Bock, 2025. All rights reserved. To receive all new posts by email, please subscribe here.