Reading Agave Leaves

What is it saying?  

If you are not familiar with Agaves, it might seem they don't change all that much, but lighting conditions affect them as much as any other plant.  For example...
Here's a small Agave parryi truncata grown all its life in full sun:
  This is also an Agave parryi truncata of the same size and age as the first.  Note the elongation of the outer (oldest) leaves:
 Why does it look so different?  Because it was covered up by a mass of Cistanthe grandiflora.  It was growing in darkness.  The newest, innermost leaves resemble the previous Agave, because this plant has been back in the light for several months.  In low light levels, the leaves elongate and flatten out so they and the plant's central growing point can maximize what light they receive.  

Here's Agave ellemetiana, which doesn't require nearly the sun that A. parryi does, but it displays the flattened posture of an Agave that would like more light.
Same thing with this A. gypsophila.  The rose that has shaded it was described as "compact".  Hah!
Another example:  Agave pygmeae 'Dragon Toes' was shaded out by an oak tree.  Note that while the newest leaves at the center of the plant are vertical, the oldest leaves are horizontal, in an attempt to gain more light exposure.  Note also that there is no curl at the sides of the leaves--they are quite flat--again, to maximize light exposure. 

From under lit to over lit.  Here's a mild case of sunburn on an Agave guiengola.  If the damage is superficial, the bleached area will gradually green up again.  More severe damage is permanent.
Slightly more sun damage and some dessication on this A. gypsophila 'Ivory Curls'--pinkness and wrinkles.  In addition, the leaves are curling inward to reduce their sun exposure.  Time to water.
Here is an Agave at the Desert Museum in Tucson, Arizona.  Permanent sun damage to those oldest leaves, and a plant grown "hard"--in extreme conditions.  Note also that the leaves are upright, not flattened out:  no additional sun exposure desired. 
 photo agave9926_zpse1ee7419.jpg
This Agave ocahui suffered damage at some point, though it has  recovered, because the central (newest) growth looks healthy and in excellent shape--no brown tips.  Perhaps it was planted in summer heat, or it got insufficient water when working to establish itself.
 Here is a more subtle difference--'Joe Hoak' in full sun is upright.  Compare the way the central growing point is surrounded by leaves with the form of the shaded A. ellemetiana:
 In morning sun and afternoon shade, 'Joe' flattens out slightly:
Here's 'Joe' stressed by moving from a mostly shady nursery bed to its all-day-sunshine permanent home.  The leaves are folding in on themselves, and they are also quite thin in texture--not fully hydrated:
I should probably shade this 'Joe' for a few weeks, until the root system recovers and begins to grow again, to avoid damage.  Two commenters kindly reminded me that all plants moved from shady conditions to fully sunny ones need gradual introduction to the sun to avoid stress.
Stressing:  the "taco fold"
 There, that's better!
Here's another example of a heat/drought/sun stressed Agave, Agave sebastiana.  Note the "taco fold" of the leaves and drying out of the leaf tips. The plant is trying to protect itself and conserve moisture.
 Not a sunlight problem, but Agave americana 'Medio Picta Alba' has a tendency to get brown marks from water sitting on the leaves.  Best to avoid water sitting in the leaves by planting at an angle, so that water drains, or by avoiding overhead watering.  
I have no examples to offer of rot, edema, bacterial/fungal infections, or freeze damage--Agaves like it here--so my leaf-reading is limited, but the effects of light are interesting.   

Keep in mind that many Agaves are native to higher elevations and are found in open pine and oak woodlands.  That means cooler nights, somewhat cooler temperatures, partial shade, and excellent drainage.  There are relatively few Agaves native to the extreme low desert conditions of areas like Phoenix or Palm Springs with summer temperatures over 100F (38 C) for weeks at a time.  A few Agaves, like Agave attenuata or A. ellemeetiana, are nearly tropical in that they can take significant shade, and regular water (given good draining soil). 

So, after seeing what light can do, Test yourself:  what's wrong with this 'Snow Glow'? 
 Nothing.  Absolutely nothing.

Comments

  1. Agaves 101. Very instructive course. I shall now look at my agaves more knowingly and therefore get more enjoyment out of them.

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  2. The leaves can tell you a lot about how the plant is coping with its environment, very clever plants. The Agave Ellemetiana and Joe Hoak are beautiful plants, so too Snow Glow.
    xoxoxo ♡

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    1. They are fascinating in their response to the sun, sensitive and aware. We share the planet with marvelous living things.

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  3. Poignant...especially the last two images when it's easy enough to overthink something

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  4. Thanks for the lessons in Agave leaf-reading. I have some Agave americana pups that are not doing well, I think maybe they're not getting enough water. I need to remember not to fall into the trap of thinking they never need water.

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    1. They can take quite a bit if it is not too cold.

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  5. We should have teamed up and both posted on this topic at the same time. After all I have examples of all the uglies you mention: rot, edema, bacterial/fungal infections, and freeze damage. Thankfully not all going on in my garden right now, but over the years.

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  6. Thanks. Very enlightening post. Snow Glow is AWESOME. MUST HAVE. GOTTA HAVE. OHHHHHHMY

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  7. Great post! My biggest mistake, generally speaking, is not giving new acquisitions (many of which aren't used to full sun) enough time to acclimate to their new spot. Not such a problem at this time of year (yet) but definitely in the summer. I've had my fair share of burned agave leaves to deal with!

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    1. So much easier to plant them in late fall--but it isn't always possible--and then we get a terrible late fall heat wave...

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  8. Maybe if I can pick up on some of these subtle hints I might be able to avoid the sudden death syndrome (guess it's not really so sudden).

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    1. Being very observant--look what it did for Sherlock Holmes.

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  9. The takeaway lesson is....I need more pretty agaves like Snow Glow and Joe Hoak. Medio Picta alba is new in my garden this year and we have had rain so I'll check for standing water on the leaves.

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    1. You got rain? Real rain? Was it utterly wonderful? Sigh.

      Yes, that Medio Picta seems far more vulnerable to marks and marrs and blotches and scars...compare with parryi whose perfect silver skin is like Teflon (at least here).

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  10. Great post, Hoover! Two years ago I had sun damage after moving the agaves outdoors but not protecting them enough at first. What I hadn't realized until you mentioned it, was that some of the agaves recovered from being scorched, like A. scabra. I used to worry about too much spring rain, but after that lesson, I am also very careful about their first weeks of spring sun.

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    1. Good point from you and Gerhard about gradual introduction to stronger sunlight. I must add that.

      Scabra is a beauty! I love the sandpapery textured ones.

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  11. Thanks for this awesome lesson! I know understand what my flattened looking lovelies are missing - light! Oh well, maybe they will have to move out into the parking strip, but even that isn't all sunny. That 'Snow Glow' is gorgeous!

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    1. Plants will tell us what they want, we just have to listen. I'm still learning!

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  12. This is a good "to-keep-on-file" post, I had never thought of this. Especially seeing a client who's overwatered and his Agave bracteosa: all yellowish, grew too fast (I should have gotten concern then), and some now have spots on leaves.

    The differences in light and the effects on their forms are great to see.

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  13. I need to take these lessons out into the garden to check the condition of my own Agaves - I know some are suffering from sunburn but I'm less sure about their hydration. What are your thoughts about Agave pups? I'm always nervous about putting them in full sun while they're young.

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    1. My thought is the same as about all other plants here: best planted in late Autumn, so they can establish before summer hits.

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  14. Great post with terrific illustrations! I could provide examples of fungus, sunburn, hail damage, cold and related rot [weeps]... Damage limited to just a few species, interestingly enough. Most of my agaves seem pretty tough. The plants I lost to cold/rot are gone for good, but I'm giving the others a chance to grow out of the damage. We'll see.

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    1. Interesting--which ones failed for you? I had a little hail damage a few years ago on an attenuata, but it produces enough new leaves the damage was soon covered up.

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  15. Fabulous information...I just found this, a little late in the game. I have forwarded it to my mother, the proud mom of Oscar, the Agave parryi from Cistus. She's having Agave issues, hopefully this will help.

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    1. Thanks, I hoped it would be helpful. Best of luck to Oscar. He's a tough one--he can make it. :)

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  16. Okay so my problem with mine is that the leaves arent rolling up like a taco but the actual whole leaf is kinda humped over and twisting around the plan ..like the lower leaves are turning around the inner leaves like a tornado lo .

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    1. What species of Agave is it, do you know? What are the growing conditions it is getting? Do you have a photo of it on the internet anywhere? Sounds strange...

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  17. Thanks for this...observation then education, and remedial action. I have learnt to look a little harder at my plants and understand.

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    1. Happy you found it of interest. Thank you!

      I've learned if I just pay attention (sometimes for years) plants will tell me how they are feeling.

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  18. Hi - thanks for the good information. I've had many agave for many years. Lately my variegated ones are showing too-pale greens and yellows (Desmettiana; Am. marginata, etc.). I always transition very slowly outside in spring. All in pots. Not seeing much difference if I put them in full sun or pt. shade. Really don't think I'm overwatering. How do I get the strong variegation back? Fertilize?

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    1. Thank you, happy you found something of interest.

      The faded leaves--are they the brand new leaves or the older ones that have been on the plant quite a while Are the new leaves richer in color? Here with our near-constant sunshine the oldest leaves on some Agaves do develop a washed out look in contrast to the newest ones.

      If you are growing them in grit that has no nutrients, you might try a little bit of fertilizer to see what happens if your temperatures are not too extreme at the moment. (Growth stops in weather extremes.)

      I've never ever given an Agave fertilizer. There's a discussion on Agaveville--most people don't, some do. See: http://www.agaveville.org/viewtopic.php?t=5708

      I will say this from growing experience here: I've got some 'Blue Glow's growing in super rich soil (silty loam rich with compost), some irrigation, and others growing in very,very poor soil (rocks and dust), almost zero irrigation. The 'Blue Glow' in rich soil are stunning, of a deep, intense color. The ones in poor soil are more pale by comparison. (though still beauties).

      Did that help?

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    2. Interesting! The plants are uniformly paled-out. Looks like the saturation was reduced in photoshop. My Blue Glows look great, but the variegated species look pale. My container medium does have some nutrients. I'm experimenting now with some pups in various light and other conditions. Thank you again.

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  19. My agave plant is in a pot planted by the plant shop and placed in my window with some sun. It now has completely brown soft leaves (not folded) - did I water too much or too little? I gave it just a little bit if water every second week the last year. I have no fertilizer. Can it be saved?

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    1. Hello Anonymous,
      is the very center of the plant brown and soft, or does it seem to be alive?

      Why do I ask? The growth point of an Agave is the center of the plant. If that area is alive, the plant is alive. If the entire leaf area is soft and brown, it is most probably dying, or dead.

      Pull it out of the pot and have a look at the entire plant, including the root system. Healthy agave roots are plump and whitish.

      If the plant is dead: some thoughts. Does the pot have drainage holes? This is mandatory. Water must be able to drain from a container.

      Another consideration: sun coming through a window can be extremely hot and cook a plant, even an agave. Also, in a very cold climate, being next to a window can be too cold for a plant in the winter.

      Sorry I cannot be more helpful, but without more information, that is what comes to mind.
      Best wishes -- Hoov

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  20. My Blue Flame agaves were planted last fall in a full-sun location, and the center of the plants still look healthy. Over the summer, the plants looked sun scorched and the outer leaves continue to die off. (It's also possible that they were under-watered). As I've removed the dead leaves, the stems are quite long now. I may try to replant them in another area that gets partial sun, or simply replant the pups that are growing. Can you recommend any types of agave that are suitable for full-sun exposure in a Phoenix desert garden?

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    1. Agave deserti, Agave colorata, Agave macroacantha might do. In the Phoenix area you also have the issue of Agave snout weevil to manage. You have an excellent resource there in the Desert Botanical Garden--check them out. Fun place to visit and they have people there who can advise you as to what would be best for your particular situation. Best wishes and good luck!

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  21. I live in Wisconsin . I planted my agave that I purchased in Fl in my south exposure garden in Wi . I brought it indoors when temps were consistently below 50 during the day. Average temp in house is 70 45% humidity indirect light my leaves have brown spots some with yellow around the brown spots how much and often should I water I hope it doesn’t die before I can take it back outside in may

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    1. Do you know what species or cultivar of Agave you have? That matters. Some can handle a lot more water than others.

      Generally Agaves are dormant in winter and in active growth in spring and early summer, which is when they need watering. Humidity--if it is humid water much less. In winter in the house--water maybe once a month, and not much. As much light as you can give it--grow lights would not hurt.

      For rot/disease you need to pay attention to the very center of the plant where the new growth emerges. That is the part of the plant where all the growth happens and that is what needs to be protected.

      Spots on leaves--you might treat it next mid-late spring when it is in active growth with a systemic fungicide. Watch for mealy bugs and just try to keep it going until spring arrives. If you get regular rain in spring and summer I wouldn't irrigate it at all. All day sun, as much as you can give it.

      Hard to help you as I grow all my Agaves outdoors where there is no frost and most of them live on rainfall alone--10-15" of rain for the entire year is fine for most of them.

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