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Ants in Your Succulents? What to Do

Late summer into fall, Argentine ants like to nest in the root balls of potted plants. Haworthias, aloes (especially dwarf varieties), gasterias and gasteraloes are highly vulnerable. Ants overwinter in the soil and consume the plant’s juicy core. Leaves eventually fall off and the plant dies.

Argentine ants infest a haworthia

The first line of defense is to create a barrier around your pots using ant powder or diatomaceous earth. The latter, available at garden centers and online, is the best “green” solution. (Go to my Useful Tools page for more about it.)

Rinse ants out of the rootballIf an infestation is well underway—ants swarm when you water the pot or tap it on a hard surface—unpot the plant and wash the roots until pests are gone (you may want to wear gloves). Before replanting in fresh soil, place a square of fine-mesh screen in the pot to keep ants from re-entering the drain hole. I know it’s overkill to buy a roll of screen for a single pot, but really, you should be using it in ALL your pots. It’s surprising how quickly you’ll go through it, especially if you repot your plants often. A role isn’t expensive and you can always share it with friends.

Pot in a moat of waterMove the plant to a different location and/or surround it with a moat (ants can’t swim). Add water to a bowl or other shallow container and, to keep the drain hole above water, set the pot atop rocks or gravel. Be vigilant until the weather cools in October.

Mealy bugs on aloe

Ants “farm” other pests for their sweet secretions. The best preventative is good air circulation. Aphids attack new growth, and mealy bugs (shown below) nestle under leaves and in leaf axils. Spray with isopropyl alcohol (70%). Isolate plants you’ve treated, and trash any that are badly infested. Indoor plants are especially susceptible, so run a fan in the room in which you overwinter your succulents. If you find pests on one plant, be sure to check its neighbors.

Also see the “Pest and Damage Control” section of Designing with Succulents, 2nd ed (pp 137-142); the “Pests and Diseases” page of my website, and my YouTube video, “Oh, No! Something’s Wrong with My Succulent!”

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How to Water Succulents

Succulents—fleshy-leaved plants from hot, dry regions—are designed to live off water stored in their leaves and tissues in order to survive periods without rainfall. But this doesn’t mean you shouldn’t water them at all. In their native habitats, succulents can look pretty ratty during times of drought, and those that are not yet established may not survive.

Succulents do appreciate water and look best if given it regularly…up to a point. Their roots simply aren’t set up to handle too much water. They certainly won’t survive in mud. Don’t assume that adding rocks to the bottom of a nondraining pot provides drainage. This basically creates a bacteria-filled soup that can rot roots. On the other hand, don’t assume that a pot must have a drain hole in order for succulents to be healthy and happy. (I know it’s counterintuitive…but when you read why, you’ll see it makes sense.)

How to water succulents in pots and in the ground

Aim to keep soil about as moist as a wrung-out sponge. About once a week should do it. Water thoroughly to soak the roots and flush salts. For succulents in containers, that means until water drips out the bottom of the pot. Let common sense prevail: water more during hot, dry spells and less or not at all during periods of high humidity, cool temperatures and rain.

Do succulents need drainage? Not necessarily!

How to water succulents in non-draining containers

They’ll be fine if they’re not overwatered. It’s not drainage that’s important so much as avoiding root and stem rot, which succulents are prone to if they sit in water. When given less water than is optimal, they’ll draw on moisture stored in their leaves (which is the very definition of a succulent).

I water my terrarium succulents by dribbling water onto their centers or inserting a medicine dropper full of water at each one’s base. As soon as I see through the glass at the bottom that the sand is moist, I stop. Underwatered succulents tend to grow very little, which is a good thing because they don’t outgrow the container. You could never do this with most other plants, which when given too little water, will dry out and die.

DO NOT add a layer of pebbles or activated charcoal to the bottom of a nondraining container, assuming that this “provides drainage.” Water that pools at the bottom of a planted bowl becomes a microbial soup that leads to rot. It’s OK to add lava rock (pumice) to soil or sand to help absorb excess moisture, but don’t assume that it “provides drainage” either. Remember, the point isn’t to provide drainage, but to water the plants so minimally that it isn’t needed.

For more about growing succulents in nondraining containers, see my videos, Succulents in Silver (3:58) and Succulent Desk Buddies, DIY (4:15).

What about rain?

Succulents do best in areas of winter rainfall that falls intermittently and doesn’t exceed 20 inches a year (of course there are exceptions). When rain threatens to be excessive, move potted succulents beneath your home’s eaves. Place patio umbrellas with concrete bases for stability in the garden to keep rain from soaking your in-ground succulents. Channel runoff away from garden beds. Move and replant succulents in low-lying areas where water puddles. Topdress the soil around the plants with several inches of pumice to absorb excess moisture.

See my videos, Why Rain is Good for Potted Succulents (0:53) and Post-Rain Must-Do’s for Succulent Gardens (3:51)

Overwatering concerns

The rule of thumb is to let the soil dry out (or nearly so) between waterings. An occasional overwatering won’t harm most succulents providing the soil is fast-draining. If water has collected in a pot saucer, remove it so roots don’t sit in water.

How to tell how much water a succulent needs

The fatter the succulent or the fleshier its leaves, the more water it stores in its tissues and the less water it needs (and will tolerate). Cacti in general are less tolerant of overwatering than smooth-leaved succulents. See my video, Why Succulents Rot and How to Prevent It (2:01)

The more susceptible an in-ground succulent is to rotting from excess moisture, the higher it should go on a berm or mound of soil.

Also on this site: 

How to Fertilize Your Succulents 

Fertilize succulents when they’re emerging from dormancy and beginning their annual growth spurt, which for most is [Continue reading]

Watch How You Water! Summer Care for Succulents 

OK, we all know that succulents are low-water plants. But they’re not “no-water” plants. Although they may survive without… [Continue reading]

Prepare Your Succulents for Rain Storms
Succulents, which come from arid climates, may rot. Stems or trunks turn squishy and collapse… [Continue reading]


 

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How to Stress Succulents (And Why You Should)

Plenty of sun brings out brilliant reds and yellows in certain succulents, but how much to “stress” the plants varies depending on where you live, the time of year, and the kind of plant.

If there’s a good thing about our too-hot Southern California summers, it’s that heat makes certain succulents stunning. Give aloes and crassulas a bit more heat, sun or cold and less water and richer soil than they really want, and they’ll turn brilliant shades of orange, red and yellow. This doesn’t harm the plants, which I deem “well-stressed” when they show the brilliant colors they’re capable of. A case in point is Aloe nobilis, which in my garden grows in nutrient-poor decomposed granite with minimal water.

Aloe nobilis. Left: winter (cool temps, bright shade). Right: summer (full, hot sun).

In winter, the same plant reverts to green.

Such “stressed” succulents—which seal moisture in their leaves as effectively as Glad-Wrap—are fine. They perk up and send out new growth when the weather cools and the rains return.

Not all succulents turn shades of red, pink or orange when stressed, in fact, the majority don’t. But many common aloes and crassulas do, plus certain kalanchoes, euphorbias, sempervivums, sedums, aeoniums and echeverias. Agaves normally don’t; the one above is an exception. The reason is it’s post-bloom and dying, which has revealed the anthocyanin in its tissues. In the same way deciduous trees turn color in autumn, sunset hues become visible. The pigment also is found in berries and fruits—and is considered a powerful antioxidant. Anthocyanins, according to Wikipedia, “are not synthesized until the plant has begun breaking down chlorophyll, it is presumed for photoprotection…” i.e. protection from excess sunlight, much the same way melanin tans skin. Wikipedia also wisely states that “plants with abnormally high anthocyanin quantities are popular as ornamental plants.”

After seeing my YouTube video, “How to Stress Your Succulents…and Why You Should,” a non-gardening friend observed, “I’d probably stress them so much, they’d croak.” Good point. How do you give a succulent the right amount of stress, but not too much? And how do you know which are worth stressing, and which aren’t?

Basically, observe the plant. If it’s leaves are margined or tipped in red, it’s a likely prospect. But if excess heat, sun or cold makes its tips shrivel and turn beigey-gray, it’s suffering. Move it to a kinder location, keep the soil moist (but not soggy), and/or repot it. Also check its roots. The problem may be that roots can’t access moisture and nutrients, as in the case of a cutting that’s sitting atop the soil instead of snugly planted.

This specimen of Crassula ovata is beautifully stressed (how’s that for an oxymoron?). Its leaves have reddened due to less water than the plant would like plus more cold than jade prefers (frost will turn the leaves to mush, but temperatures near but above freezing reddens them).

Most succulents—especially those with fat, fleshy leaves—can last weeks and sometimes months without water, even in hot sun, nipped by frost, and/or rooted solely in gravel. But eventually they need a respite, lest stress become life-threatening.

A few common succulents that redden when stressed:

Kalanchoe luciae

 

Aeonium canariense

 

Aloe dorotheae

 

Learn more in my book, Succulents Simplified“The Well-Stressed Succulent,” pp. 54-55.

Also on my YouTube channel:

Most succulents are sun lovers, but how much do they really need? And what happens if they get too much or too little light? (Filmed at the Succulent Extravaganza.)
How to Stress Succulents and Why You Should, my first video now with 80,000 views, gives additional examples and includes before-and-after photos.

 

 

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Summer Care for Succulents: Heat and Sun Concerns

Don’t let summer sun and heat harm your succulents! Heat, unlike frost (temps 32 degrees F and lower), usually isn’t a concern for succulents. Although some tend not to thrive in temps above 80 or 90 degrees F, the majority can handle more than you’re personally comfortable with…as evidenced by greenhouse temperatures that soar into the triple digits on summer days. However, heat plus sun can be deadly to succulents. Unless they’re desert cacti or agaves, most smooth-leaved succulents need sun protection in summer, especially above 80 degrees.

Summer-stressed Aloe bainseii tree

If you live in an arid climate like Southern CA’s and grow succulents in the open garden (as I do) ~

— Know your property’s orientation to the sun. In North America, plants growing on your home’s north side will get the least amount of sun exposure; those on the south, the most. East-facing gardens like mine get morning sun and afternoon shade. Gardens facing west have afternoon sun and morning shade.

— “Bright shade” (no direct sun but not deep shade) is ideal for non-desert succulents in mid-afternoon when temperatures peak. Bright shade is essential for low-light succulents such as haworthias, gasterias, euphorbias, faucarias, sansevierias, echeverias, and anything light-colored or variegated. (Of course there are exceptions; for the requirements of specific plants, see the “Succulents A to Z” chapter of Designing with Succulents.)

— Whenever you buy a new plant, notice where it was located in the nursery. Was it out in the open or beneath shade cloth? Even if it’s a “full sun” succulent—like an agave—if it was growing in a sheltered area, it’ll need to be “hardened off” (shaded, especially in the afternoon) until it acclimates. Such exposure is similar to tanning: Start with half an hour of sun and increase it by an hour or so each day.

— Give aloes and crassulas enough sun to turn hues of red and orange but not so much that leaf tips shrivel or burn—at least half a day, ideally morning. (See “How to Stress Succulents and Why You Should.”)

— Because sunburned stems are less able to transmit moisture from roots to leaves, cover exposed, horizontal stems of trailing succulents (aloes, senecios, othonna and the like) with dry leaves or mulch.

— Protect newly installed plants and in-ground succulents susceptible to sun-scorch with temporary shade structures. I use old window screens secured with bricks, but you can buy shade cloth at any home improvement store. Leafy branches trimmed from trees works, too; insert branches in the ground next to the plant you want to protect, making sure it’s shaded on the side that gets the most sun.

— Plant trees and shrubs that will provide shade where needed during long, hot summer afternoons. (For low-water varieties good in succulent gardens, see the Companion Plants chapter of Designing with Succulents, 2nd ed.).

When it’s too late (what sunburn looks like)

Beige patches on succulents indicate sunburn. Cells have been irrevocably damaged, which turns them white or putty-colored. This looks similar to frost damage, but instead of leaf tips, you’ll see patches on leaves. An otherwise healthy plant will outgrow the damage. If marred areas are on outer leaves, so much the better; new growth from the center of the rosette will conceal sunburned areas over time. In any case, lower leaves, damaged or not, naturally wither and fall off. Depending on the succulent and the season, recovery from sunburn may take several months to a year.

More Info on this Site:

How to Water Succulents in Summer.  OK, we all know that succulents are low-water plants. But they’re not “no-water” plants. Although they may survive without irrigation during the heat of summer, they’re unlikely to be lush and healthy. Be sure you… [continue reading]

Aloe nobilis, in bright shade on left, in full sun on right

How to Stress Succulents (and Why You Should). Plenty of sun brings out brilliant reds and yellows in certain succulents, but how much to “stress” the plants varies depending on… [continue reading]

On my YouTube channel:


Succulents, Sun and Summer. On an 89-degree day in my garden, I show you what’s in bloom and lookin’ good (or sadly dreadful), and explain how to evaluate the health of your in-ground succulents, small and large.

Twelve Low-Water Trees for Succulent Landscapes.  I help you evaluate garden areas in need of shade and select trees to plant when the weather cools in the fall.

Sun and Your Succulents. Most succulents are sun lovers, but how much do they really need? And what happens if they get too much or too little light? (Filmed at the Succulent Extravaganza.)

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Will Succulents Recover from Frost Damage?

Will succulents recover from frost damage? It depends. Here’s a southern California nursery’s display garden before nighttime temperatures dropped into the mid-20s F:

IMG_9517annotated_resized

Here’s the same Euphorbia ammak ‘Variegata, after the frost:
IMG_1410_annotated_resized

Likelihood of recovery: Nil. Too much of the tissue was damaged. But what about the Euphorbia tirucalli ‘Sticks on Fire’ behind it? It’s hope of recovery is excellent because only the top growth froze. It protected the stems underneath, which are still healthy.

IMG_3059annotated_resized

If something similar has happened to your plants, succulent or otherwise, once all danger of frost has passed, prune the dead top growth and the plant will be good as new…except smaller, of course!

How about the frozen aeonium below? Pretty much hopeless. But look a the Sedum ‘Angelina’ surrounding it. It’s a succulent too, and perfectly fine!
IMG_1237resized_annotated

Why does frost kill some succulents and not others? A lot has to do with where a particular kind of plant originated. Succulents, which store water in their leaves to survive drought, are mostly from dry, hot climates. But some are from dry, cold climates. See my Wall Street Journal article on this topic.

Related articles and info:

An excellent book about succulents that survive freezing temps is Hardy Succulents, by Gwen Kelaidis, illustrated by Saxon Holt.

Screen shot 2016-01-05 at 7.59.00 PM

My books also have info on growing succulents in challenging climates and how to protect them from frost and excess rain ~

 

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How to Make Succulents Bloom

Is there a way to make succulents bloom? Yes and no. It partly depends on a plant’s age. It may not be large or mature enough to gear up for reproduction (which is the point of flowers). But there IS something you can do to make a succulent bloom if it’s just sitting there, sulking, with no apparent reason not to produce a prized flower spike—if it’s the proper season. Most succulents bloom in spring and summer, but others (like aloes and crassulas) flower in midwinter.

So here’s the secret: Succulents (most plants for that matter) need light in order to flower. Sun is essential to photosynthesis, which creates energy and fuels new growth. All plants (actually, all living things) want to reproduce, and for plants that means being robust enough to bloom. Because most succulents come from warm, dry climates, they require a lot of light.

 If this aloe could talk, it would say, “I’m starved for light! I may not be able to bloom! Help!”

Aloe maculata (A. saponaria)

Above: A specimen of Aloe maculata growing indoors in the Seattle area. Although it’s healthy, it has flattened and elongated its leaves in order to expose as much of its surface as possible to light. The term for this is etiolation (et-ee-oh-lay-shun).

Aloe maculata (A. saponaria) in bloom

Above: This is how Aloe maculata looks with half a day of sun and half a day of bright shade. Even in these near-ideal conditions, the rosette and flower spikes are leaning in the direction of greatest light. Leaf tips have protected themselves from too much sun by turning reddish-brown. The pigment it’s similar to melanin, which causes skin to tan or freckle.
And here, in all-day sun with minimal water, a similar specimen’s leaves have shortened to reduce evaporation. (Note how those in the first photo are much longer.) Sun exposure is evidently somewhat harsh because it has reddened even more. The horticultural term for this is “stress,” which is aesthetically desirable because it enhances color and symmetry. This plant may be a bit too stressed—leaf tips have scorched and growth has slowed—but look closely: It’s in bud!
What to do if you live in an often overcast climate or grow succulents mainly inside? This is from my website page, How to Grow Succulents in Seattle (Northern Climates):
Indoors, set them near windows that face south or west. Don’t bother with north-facing windows, but if your windows face east, do collect and enjoy low-light lovers such as haworthias and gasterias. [Read more]
About Aloe maculata: Formerly known as Aloe saponaria (soap aloe) because the gel in its leaves lathers like soap, it is one of the few potentially invasive succulents, capable of sending up new plants from horizontal roots a few inches below the soil surface. Baby plants can pop up three feet or more from the mother! I have a colony of Aloe maculata in a rocky area of the garden where they can’t get into trouble, because I love the flowers, which are branching—unlike the columnar spikes of many other aloes. They don’t make good cut flowers, though, because cut stems ooze a mucilaginous gel. Aloe maculata is not often found at nurseries in Southern CA because there’s minimal demand for it (it’s a common passalong plant). A similar aloe that is better behaved, not toothed, often sold in nurseries, and much more prized in cultivation is Aloe striata (coral aloe). See it and others on my website’s Aloes page.

Related info on this site:

Summer Care for Succulents: Heat and Sun Concerns
Don’t let summer sun and heat harm your succulents! Heat, unlike frost (temps 32 degrees F and lower), usually isn’t…[Continue reading]

Aloe nobilis, in bright shade on left, in full sun on right

How to Stress Your Succulents (And Why You Should)
Plenty of sun brings out brilliant reds and yellows in certain succulents, but how much to “stress” the plants varies depending on [Continue reading]

On my YouTube channel: Sun and Your Succulents (1:41)

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How to Grow Succulents Indoors

If you’re wondering how to grow succulents indoors, basically you need to outfit a basement, sun room, spare room or alcove with tables and shelves that can withstand moisture, plus lights and a fan that run on timers. Fortunately succulents need very little water. Dribble a little at the base of each plant every three weeks or so, enough to hydrate the roots but not so much it puddles on the floor.

Place your succulents near a window. Maximum sun exposure is on the south and west sides of your house. The farther north you live in North America, east will provide bright light, but not enough for crassulas, echeverias and aloes to maintain their red hues. [Read more] 

OR…

Install grow lights. Experts in growing succulents in gray-sky climates recommend T-5 grow lights.

Agrobrite FLT44 T5 Fluorescent Grow Light System, 4 Feet, 4 Tubes, about $120 on Amazon.

 

Create a “light island.” Shown below is arguably the ultimate indoor plant-shelf unit. Made of lightweight, powder-coated aluminum, it has adjustable lights with energy-efficient, full-spectrum bulbs; plastic drip trays; and wheels for easy positioning. Three shelves provide 18 square feet of growing space. From Gardener’s Supply Co.; about $600. 

Get a timer which automatically turns the lights on at, say, 7 a.m. and off eight hours later. I like this one, below, because it has multiple outlets:  Titan Apollo 14, about $26. 

Watch the temperature. If it falls below freezing (32 degrees F) many succulents may show long-term damage (or die). This indoor thermometer is digital and also has a humidity gauge. But what I love about it is that it keeps daily high and low temps for 24 hours!

AcuRite 00613 Humidity Monitor with Indoor Thermometer, Digital Hygrometer and Humidity Gauge Indicator, about $10 on Amazon.

 

Related info on this site: 


 

 

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Agave Snout Weevil Prevention and Treatment

VIDEO: Agave snout-nosed weevil (30 sec.)

The agave snout-nosed weevil is a half-inch-long black beetle with a downward-curving proboscis that enables it to pierce an agave’s core, where it lays its eggs. Grubs hatch, consume the agave’s heart, then burrow into the soil to pupate. The weevil (Scyphophorus acupunctatus)—once prevalent only in desert regions and Mexicois spreading rapidly throughout the US and abroad, earning it the dubious distinction of being one of the “Top 100 Worst Global Invasive Species.”

The agave in the middle shows signs of snout weevil infestation. This a block from my home (eek!)

According to the Global Invasive Species Database, “Scyphophorus acupunctatus is becoming a major pest of native Agavaceae and Dracaenaceae species worldwide. From Mexico, it has decimated populations of Agave crops there, in particular those used in the tequila industry. The importation of ornamental Agave plants worldwide has facilitated S. acupunctatus to establish in many parts of the world, particularly in Central America and the Caribbean, in Africa, Asia and South America.”

Is your agave infested? Look for damaged tissue where leaves meet stem. The lowest leaves will appear wilted, and may slope unnaturally downward while the center cone remains upright. The plant, no longer anchored by roots, will rock when pushed. When an infestation is well underway, it’s possible to shove the agave over onto its side. It’ll break at soil level, revealing a mushy, foul-smelling core infested by plump, squirming, half-inch, cream-colored grubs with brown heads.

Agave snout weevil

Above: an agave’s grub-eaten core resembles a sponge.

PamPenick_AgaveWeevilLarva_R

Above: Close-up of a snout-nose grub.

In my YouTube video, “Agave Snout Weevil Prevention and Treatment,” I demonstrate how to inspect nursery agaves, show resistant varieties, and interview agave expert Kelly Griffin at an infested colony of Agave americana. Kelly also talks about applying a systemic insecticide as a prophylactic (preventive) option.

How one homeowner does it: Succulent collector Jeanne Meadow is well versed in the fauna and flora of her large garden in Fallbrook, California, midway between Riverside and San Diego. Jeanne, an ace researcher, has become an expert on the agave snout-nose weevil. She says people tend to assume most nursery plants are pest-free, yet that’s the primary way snout weevil enters gardens. When an agave in her garden shows signs of infestation, she removes it and every plant for several feet surrounding it. Then she sifts the soil and picks out grubs and beetles. “It’s a huge undertaking,” Jeanne says. “Fortunately they’re slow crawlers.”

To remove a diseased agave, here’s Jeanne’s method:
1. Place a tarp around the plant.
2. Position a wheelbarrow nearby. Make sure the tarp covers the ground between it and the agave.
3. Dig up the agave and put in the wheelbarrow.
4. Dig out more dirt to a depth of 12 inches (deeper if you find grubs) and about 12 inches from where the base of the plant was.
5. As you transfer the soil to the wheelbarrow, inspect it for grubs and weevils.
6. The beetles “are hard to crush,” Jeanne says. “I use a hammer.”
7. Take the wheelbarrow to a paved area, like your driveway, so if beetles escape they’re easy to spot.
8. Transfer into heavy-duty trash bags, sprinkle contents with insecticide, and triple-tie.
9. Seal any rips with duct tape.
10. Drench the soil where the agave was with insecticide.

Aren’t insecticides bad for the environment? Although neither Jeanne nor I advocate inorganic pesticides, and we certainly aren’t licensed pest control experts, we strongly believe that the responsible thing to do is to share knowledge with others based on research and personal experience, and to do what we can to prevent the beetle from spreading. “This is an emergency situation,” Jeanne says. “The pest is spreading like crazy and has to be brought under control.” According to agave experts, growers, and pest management specialists, the best approach is preemptive: drench the soil around healthy agaves with a systemic insecticide that has imidacloprid as the main ingredient.

Hire a licensed pest control expert. The going rate is $175/hr., but you’ll know for certain that everything is done safely and protects the environment while eradicating the pest from your property. One in the San Diego area is Chris Mizoguchi, chrisagpestcontrol@hotmail.com.

How to preventatively treat your agaves. The goal is to drench the agave’s roots. Twice a year, in spring and fall, here’s what I do:

1. The night before, soak (hose-water) the soil at the base of each agave to aid penetration.
2. Read and follow the label directions. Be sure to wear gloves and protect your skin and eyes.
3. To mix the solution, I use a hose, a 3-to-5 gallon bucket, and a stick for stirring. Product labels don’t say how much concentrate per gallon of water for agaves, so I go with the ratio for shrubs. (If using Compare-N-Save Systemic Tree and Shrub Insect Drench, it’s 3 oz. per foot of height per gallon of water.)
4. Agaves naturally funnel rainwater water to their roots, so if you slosh the solution where lowest leaves meet the core, you’ll effectively drench the soil below them at the base of the plant.

Note: Avoid doing this in temperatures above 80 degrees F. High temps diminish the insecticide’s effectiveness and may even harm plants already stressed by heat. 

Don’t panic, but do pass the word. It’s only a matter of time before weevils in neighbors’ agaves find their way to yours (and vice-versa). The unfortunate reality is that agave owners who do nothing are inadvertently aiding the proliferation of a serious pest, and may incur the expense and inconvenience of removing prized, immense and spiky plants. I suggest you:
— Send close neighbors a friendly email with a link to this page.
— Post about agave snout weevil on your neighborhood’s online forum. If possible, include a photo of an infested agave.
— Copy-and-paste part or all of this into an email to the editor of your community newsletter. (All I ask is to be credited. With, of course, a link.)

Don’t assume your agaves won’t be affected. Although snout-nosed weevils can’t fly (yes, there are such things as flightless beetles), they sure can walk. I first suspected that snout-nose had arrived in my backcountry community northeast of San Diego when I noticed a collapsed Agave americana in a friend’s garden. I could barely believe it. She lives atop a rocky hill surrounded by acres and acres of native chaparral. Either the weevil had arrived via infested nursery stock (on a different agave most likely, seeing as the sick plant was part of an old colony), or it had walked in. I’ve since observed that it takes a captive weevil ten days to die despite receiving no water nor food. The entire time, it was mobile and capable of traveling 4 inches per second. Had I released it, it easily could have gone several blocks (at least). It also was a surprisingly good climber.

Consider: If a dying agave hosts dozens of grubs that turn into beetles, and if each takes off in a different direction, one or more will certainly find another agave.

A tiny concern. If your goal is to kill snout weevils before they spread, a systemic ought to do it, but it’s uncertain how much damage the puncture hole causes. The weevil is a vector (carrier) of Erwinia carotovora, a micro-organism that decomposes plant tissues, enabling grubs to easily consume it. I’m hopeful, and it seems likely, that the bacteria doesn’t go deeper unless spread by live grubs. Moreover, as I mention below (see “Good News”), bitten agaves have been known to recover.

GREEN ALERT: Insecticides kill beneficial insects as well as pests and may disrupt your garden’s natural predator-prey balance. Snout weevils have coexisted with agaves for millennia and are naturally preyed upon by reptiles, birds and mammals (though the spines that protect an agave from predation also protect the weevil). Systemics, as the name implies, transmit insecticides through a plant’s system, so that any bug that eats it dies. Some studies have indicated that bees and birds are not harmed by the nectar of treated plants, and that animals farther up the food chain are not at risk. Use sparingly and follow label directions. Don’t pour this (or for that matter, anything inorganic) into drains or gutters.

Weevil control without pesticides. Remove an agave at first sign of infestation and sift grubs and weevils out of the soil. (Feed them to your chickens or put them out with the trash in sealed plastic bags.) Don’t plant agaves in that part of your garden again, and watch your other agaves for signs of infestation. It’s possible that beneficial nematodes may be effective. They do kill larvae, but I’ve yet to find out if they’ll work against snout grubs. (Check back.)

Earthworm castings destroy beetle exoskeletons, advises Pat Welsh, author of Pat Welsh’s Southern California Organic Gardening: Month by Month. In Jan, 2018, in response to this post, she wrote: “Imadacloprid is killing bees. It is one of the worst ever pesticides and will end up killing us also. Instead of that, purchase earthworm castings and spread them on top of soil surrounding agaves. Keep it up. Earthworm castings kill all insect pests and are a great barrier to the ones that live in the ground under plants. Weevils walk on top of soil and cannot cross earthworm castings or they die. This is because earthworm castings contain chitinase, an enzyme that destroys chitin. The exoskeletons of insects are made of chitin.”

Good news ~
Agaves treated early in an infestation may recover, providing there’s adequate meristem tissue to regenerate new growth. (An agave’s meristem cells are at the core, or heart, where leaves join roots. It’s prime grub fodder.)
An organic control currently being tested is a pheromone trap designed to attract adult beetles in search of mates.
— Weevil-resistant Agave varieties do exist and are being selected and cultivated. (Sometimes you’ll see seemingly unaffected plants alongside diseased ones.) Tissue-culture labs make it possible to produce quantities of plants over a short period of time, which is likely the future of commercially-sold members of the Agaveaceae family.
— The weevil seems less inclined toward those with thin, flexible leaves, such as Agave attenuata; those with tough, hard-to-pierce leaves (such as agaves desmetiana, murpheyi, parryi, lophantha ‘Quadricolor’, ‘Sharkskin’, triangularis, victoriae-reginae and vilmoriniana); and those with slender, nonjuicy leaves such as agaves bracteosa, filifera and geminiflora. See photos on my website’s Agaves page.

CRW_1686_A_r

In the meantime…

Plant agaves bare-root. Before planting, remove an agave from its nursery pot, set the plant (root ball and all) in a wheelbarrow, and hose the soil from the roots. Examine the plant for beetles and puncture holes, and the soil for grubs. If a plant is infested, destroy it and inform the source nursery. Jeanne notes that when chased, weevils head back to the agave for shelter. “They don’t try to escape from the wheelbarrow.” Btw, after observing grubs kept alive in soil-filled jars, Jeanne says that when deprived of an agave to feed on, grubs don’t pupate (turn into weevils).

Grow agaves in pots. In areas where snout weevil is known to be active, plant agaves in containers like the urns shown here. You’ll know that the soil is OK because it came from a bag; you can easily get rid of infested soil should beetles show up; and when you apply a preventative drench, only the soil in the container is affected. Additional advantages are that pots elevate agaves for better viewing, enabling them to serve as garden focal points even when small. Potentially immense, pupping agaves (such as A. americana species) grow more slowly in containers, which also serve to corral their offsets.

The big green agave at left is likely a hybrid of A. salmiana; at right is A. franzosinii. In the foreground is what Jeanne Meadow calls “snout-weevil candy”: A. americana ‘Mediopicta Alba’.

Watch susceptible plants. Keep an eye on all your agaves, especially mature ones about to bloom, because they’re loaded with weevil-attracting carbohydrates. The pest seems to prefer specimens of Agave americana and its variegates (striped varieties), as well as closely related Agave franzosinii (one of the largest agaves). Reportedly, it may infest other genera in the Agavaceae family, such as Nolina, Beaucarnea, Yucca, and Furcraea. I’ve heard, but have yet to confirm, that it also attacks Mexican fence post cactus (Pachycereus marginatus) and possibly barrel cacti — but symptoms may simply be due to a different bug. After all, it’s a Pandora’s box out there.

Don’t give up on agaves! “Snout-nose shouldn’t discourage anyone from planting agaves,” Jeanne says. “There IS hope, and my garden is a great example of that.” She adds that the imidacloprid drench—which degrades over time—has had no apparent impact on her garden’s overall health and ecosystem, “including its population of beneficial insects, reptiles, birds, and amphibians.”

More info:

UC Nursery and Floracultural Alliance Regional Report, Spring 2016, “Agave Pests

Global Invasive Species Database

Desert Botanical Garden, Phoenix, AZ

Pam Penick’s blog post: “Evil Weevils! Agaves Under Attack in Austin”

Tropical Texana blog: http://tropicaltexana.blogspot.com/p/agave-weevil-eradication.html

View my 7-minute YouTube video, Agave Snout Weevil Prevention and Treatment

Note: This post first appeared in August, 2016. I’ve updated it several times, most recently in Jan., 2018.  I welcome your comments. — Debra

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Ways to Overwinter Succulents

These four ways to overwinter succulents give you several options, depending on how cold it gets where you live. Climate makes a big difference when it comes to the well-being of your succulents in winter. Most varieties go dormant in winter and are frost-tender, meaning they can’t handle temps below 32 degrees F.

These common winter conditions can lead to damage or death for dormant (not actively growing) succulents:
— soggy soil (causes roots to rot)
— excess rainfall (engorges cells)
— frost (causes cell walls to burst)

Some succulents do have a built-in antifreeze. Those indigenous to the Americas, such as cacti and agaves, or to northern climates like many sedums and sempervivums, tend to fare better than those from Madagascar and South Africa (kalanchoes, aeoniums, aloes and crassulas). But no succulents want a lot of water when dormant, nor high humidity at any time of the year. All prefer well-draining soil, bright but not intense light, and good air circulation.

If you live, as I do, where frost is occasional and lasts only a few hours (Zone 9b), plan to cover vulnerable, in-ground succulents with frost cloth or bed sheets when there’s a frost advisory for your area. In my YouTube video, Frost Protection for Succulents, I show how I do this in my own garden. In the foothills NE of San Diego at 1,500 feet, it’s subject to cold air that settles in inland valleys. My neighbors higher-up generally get no frost at all.

Ways to overwinter succulents

If you live in Zones 8 or lower, grow tender succulents as annuals or in containers that you overwinter indoors. These members of my Facebook community graciously shared their winter set-ups:

Pat Enderly of Virginia Beach, VA: Midwinter lows average 32 F. Pat brings her plants indoors and tucks them into shelving units she purchased online. Each shelf has a waterproof tray, and each unit is lit by two T5 bulbs. “They do a wonderful job of keeping my succulents from etiolating (stretching),” Pat says, adding that the lights, on timers, stay on from 7 am to 7 pm daily. Pat moves her succulents indoors in Sept. and Oct. and takes them outside in April.

Ways to overwinter succulents Ways to overwinter succulents

Candy Suter, Roseville, CA (near Sacramento): Midwinter nights may drop into the 20s F but seldom go lower than 25 F. Candy moves her succulents into a small walk-in greenhouse (center) or a gazebo (right), which she covers with 5mm plastic to hold in warmth. She anchors the plastic along the bottom, secures the seams with duct tape, and adds a small heater with a fan on the coldest nights.

Ways to overwinter succulents

Tenaya Capron of Buffalo, TX: Although average midwinter lows hover above freezing, occasional winter lows may drop into the single digits. Tenaya and her husband built this 24×20 free-standing greenhouse, which they outfitted with exhaust and overhead fans, an overhead heater, and double sliding barn doors on either end. I love the library ladder, don’t you?

Ways to overwinter succulents

Find more info in my book, Designing with Succulents (2nd ed.):
— Cold-Climate Succulent Gardens, pp. 111-113
— Cultivating Succulents in Challenging Climates, pp. 143-148

More on this site:


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Watch How You Water! Summer Care for Succulents

OK, we all know that succulents are low-water plants. But they’re not “no-water” plants. Although they may survive without irrigation during the heat of summer, they’re unlikely to be lush and healthy.

I suggest that you ~

— Check your automatic irrigation system. Trust me, it needs it, and maintaining it can mean life or death to prized plants. Watch for leafy growth blocking sprayers, clogged riser heads, and plugged drip lines.

— Pay keen attention to soil moisture during heat waves and desiccating winds.

— If the root zone goes dry, supplement auto irrigation with hose watering. (See my canary-in-the-mineshaft way to evaluate evaporation in my latest video, Succulents, Sun and Summer.)

— Water early in the morning or late in the day. Note to desert gardeners: Watering in midday heat can literally cook roots. (Eek!)

— HOWEVER, aeoniums, dudleyas and other succulents that have closed their rosettes should be watered minimally or not at all, lest dormant roots rot. The plants will revive when the rains return. (They may not make it until then, though, if in full sun. So, shade them.)

— If the ground is concrete-hard, leave a hose dripping overnight to create an underground cone of moist soil.

— Trees and shrubs want water where their canopies would naturally direct rainfall: around the perimeter of the plant.

— Add gravel topdressing around succulents (or use organic mulch for woody plants) to help hold moisture in the soil.

— Take the opportunity, when hose-watering, to blast pests, fallen leaves and dirt out of leaf axils and the centers of rosettes.

— Use a hose-end sprayer—ideally one with multiple settings—to direct water where you want it.

— A hose lying in summer sun may contain scalding water. You already know this, but your house-sitter may not, so be sure to mention it.

— If you have a hose-full of hot water, aim a fine spray skyward. Droplets will cool by the time they hit leaves.

What about potted succulents?

From my website’s FAQ’s:  Aim to keep soil about as moist as a wrung-out sponge. About once a week should do it. Water thoroughly to soak the roots and flush salts. Let common sense prevail: Water more during hot, dry spells and less or not at all during periods of high humidity, cool temperatures and rain.

ALSO SEE: Page 56 of Succulents Simplified, pp. 219-222 of Succulent Container Gardens, and pp. 134-135 of Designing with Succulents (second edition).

Related info on this site:

How to Water Succulents

Succulents—fleshy-leaved plants from hot, dry regions—are designed to live off water stored in their leaves and tissues in order to survive periods without rainfall. But this doesn’t mean [Continue reading]