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Frost and Succulents: What You Need to Know

Frost and Succulents: What You Need to Know

Depending on how long temps stay below freezing (32 degrees F), “frost tender” succulents may show varying degrees of damage. When moisture in the cells of a vulnerable plant freezes, it expands, bursts cell walls, and turns leaves to mush. In a “light frost,” leaf tips alone may show damage. In a “hard frost,” temps stay below freezing for hours, which can collapse entire plants. Succulents typically don’t regenerate from roots.

Crassulas, aeoniums, euphorbias, and kalanchoes are among the most tender succulents. A few succulents have a built-in antifreeze that enables them to survive temperatures well below 32 degrees F—below zero, in fact.

Should you be worried about your outdoor succulents in winter? It depends on where you live. See “Cold Weather Care for Outdoor Succulents, By Region.”

Your area is frost-free (lucky you!) if…

Agave attenuata grows in gardens, and the plants look like this year-round.

Cold Weather Care for Garden Succulents

Agave attenuata is the first succulent to show damage from frost in winter.

In my garden, this soft-leaved agave is the canary in the mineshaft where cold is concerned. A lot of succulents breeze through a brief frost (less than an hour), but leaf tips of Agave attenuata show damage right away.

Frost and Succulents: What You Need to Know

After a brief exposure to 32 degrees, Agave attenuata will look like this.

Such damage is unsightly but seldom fatal. See the healthy green part of each leaf? Use scissors to trim off the tissue-paper-like frozen tips [see how], cutting each leaf to a point. When you’re done, the damage will be barely noticeable. By summer new growth will have hidden those shorter, trimmed leaves. (Note: Such damage is similar to scorching caused by too much sun and heat, typical of desert climates, and by—believe it or not—wildfire.)

 

Cold Weather Care for Garden Succulents

What about an agave or other succulent that has frost damage only on its leaf tips? Don’t bother to trim them. It’ll lose those oldest leaves in a few months anyway.

Areas of occasional, mild frosts (like inland Southern CA):

Watch the weather forecast, and if there’s a “frost advisory” for your area, before dark go outside and cover your tender succulents. Frost tends to happen after midnight, with temps getting colder toward dawn. Cold air is heavier than warm, and flows down slopes and collects in low spots. Consequently, succulents in swales are more at risk than those atop berms. You may have heard that Christmas lights raise the temperature a few degrees. Yes, if they’re the old-fashioned kind. Those sold nowadays (LEDs) don’t generate heat. The succulents you have to worry about are those out in the open, with nothing above them. I sometimes stand over a succulent and gaze upward. If there are no tree limbs or eaves directly overhead, it gets draped.

I live in the foothills NE of San Diego at 1,500 feet (Zone 9b). And yes, I’ve been outdoors in my pajamas and slippers at 11 pm after hearing the weather forecast on the late-night news, shivering as I throw sheets on vulnerable plants, while my husband holds a flashlight. If frost is predicted for a series of nights, I may leave the plants covered; otherwise, I remove the sheets the next morning. To make sure they won’t blow off, I secure them with clothes pins and rocks. Do NOT use plastic. It doesn’t allow the plants to breathe.

Frost and Succulents: What You Need to Know

Frost cloth protects jades and other vulnerable succulents in my garden. See the video. 

Why cold damages 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—and those are the ones that don’t freeze. See my article in the Wall Street Journal: Showy Succulents for Snowy Climates. Among the “hardies” are:

Frost and Succulents: What You Need to Know

Stonecrops (small-leaved sedums), like those above in a Colorado rock garden…

Frost and Succulents: What You Need to Know

sempervivums (hens-and-chicks, above) of which there are numerous species and cultivars; certain cacti, yuccas and agaves (like Agave utahensis, A. montana and A. parryi), and lewisias from the Pacific Northwest.

Related Info on This Site:

Overwintering

How to grow indoors

Cold Weather Care for Outdoor Succulents

Frost damage

 

Learn more in my books:

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

Succulents Simplified:
— Protection from Frost, pp. 48-50
— Frost Damage, p. 72 and p. 77

I also recommend Hardy Succulents, by Gwen Kelaidis, illustrated by Saxon Holt:

Screen shot 2016-01-05 at 7.59.00 PM

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Oh No, My Succulents Froze!

Will succulents recover from frost damage? It depends. Here’s how frost-tender succulents looked before temps dropped into the mid-20s F, and after:

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.

If Your Succulents DO Become Damaged

Remove collapsed leaves if it’s likely they’ll rot, because that threatens the health of the plant. If instead they dry out, they’ll help protect healthy tissue from future frosts. Leave them on, then prune after the weather warms.

Preserve the symmetry of slender-leaved succulents (such as agaves and aloes) by trimming tip-burned leaves to a point, rather than cutting straight across. (See below.)

Chalk it up to experience. Now you know that particular plant is vulnerable and needs a protected location.

How to trim a frost-burned Agave attenuata

The tips of the leaves of this agave melt at 32 degrees, but the plant is usually fine. Here’s how to make it look good again—only takes a minute!

Related articles and info:WSJ article

Cold Weather Care for Outdoor Succulents

 

Winter Protection for Succulents: Products  Soggy soil, dim light, high humidity and freezing temperatures can be death to succulents native to warm, arid climates. These items will help you get your succulents through cold, wet North American winters…[Continue reading]

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

All the info you need, all in one place: 

I also recommend this excellent book about succulents that survive freezing temps: Hardy Succulents, by Gwen Kelaidis, illustrated by Saxon Holt.

Screen shot 2016-01-05 at 7.59.00 PM

Cold weather care for outdoor succulents
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Cold Weather Care for Outdoor Succulents, By Region

Cold Weather Care for Outdoor Succulents, By Region

Should you be worried about your outdoor succulents in winter? It depends on where you live.

It’s all about frost. The temperature at which water freezes—32 degrees F—is the Great Divide. Above that, most succulents are fine. Below that, most are at risk. See “Frost and Succulents: What You Need to Know.

Hardiness Zone Map

The USDA Plant Hardiness Zone Map is a good basic guideline. However, it doesn’t take into account climate variables potentially harmful to succulents.

Regional Care for Succulents, An Overview

There’s very little of North America where every kind of succulent will grow outdoors year-round. The “banana belt” is the heavily populated California coast. Of course, you can grow any succulent anywhere if you’re able to replicate the conditions it likes, either in your home or in a greenhouse. But this article is about cultivating succulents outdoors, in the garden, during the most challenging season: winter.

If you live in…

Coastal CA from the Bay Area south: You don’t get frost (at lower elevations), and humidity and rainfall are minimal, so simply make sure your succulents get good drainage during occasional rainstorms.

Cold weather care for outdoor succulents

My garden is in Southern CA inland, in the foothills NE of San Diego at 1,500 feet (Zone 9b). A freak snowfall happened on New Year’s Day, 2017. When temps rose above freezing, I hosed off the snow. The Agave attenuata at left was damaged but recovered.

Central and Southern CA inland: Frosty nights tend to follow rainy weather, December through February. Like a citrus grower, I pay attention to “frost advisories for inland valleys.” When temps are predicted to drop below 32, I drape succulents with bed sheets or commercial frost cloth made of non-woven fabric[Learn more about how I protect my garden.]

Cold Weather Care for Garden Succulents

When a non-gardening friend noticed bedsheets draped over my plants, she asked if my dryer wasn’t working (!).

Areas of hard frost: You get temps below 32 degrees that last for hours, so it’s not adequate to merely cover your in-ground succulents or shelter potted succulents beneath eaves. Move them indoors or into a greenhouse. Depending on where you live, an inexpensive temporary shelter may be OK. [See “Four Ways to Overwinter Succulents” on this site.]

Northwest and Northeast: Protect and shelter your succulents indoors (perhaps in your basement) or in a climate-controlled greenhouse. [On this site, See “Cold-Hardy Succulents for Northern Climates” for exceptions; “How to Grow Succulents Indoors;” and “Winter Protection for Succulents: Products].

Desert Southwest: You get hard frosts, so protect and shelter tender succulents indoors or in a climate-controlled greenhouse. Those that do well for you include cacti, agaves, dasylirions, yuccas and other succulents specific to your region.

South: If you get frost, see above. But even if temps stay above freezing, you’ll still contend year-round with trying to grow arid-region plants in a wet, humid climate. Find out which succulents you can grow outdoors in Florida and other states too damp and humid for most succulents.

Related info on this site:
How to grow indoors
Overwintering

Frost and succulents Frost damage

Learn more in my books:

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

Succulents Simplified:
— Protection from Frost, pp. 48-50
— Frost Damage, p. 72 and p. 77

I also recommend this excellent book: Hardy Succulents by Gwen Kelaidis, photos by Saxon Holt.Cold Weather Care for Garden Succulents

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Four Ways to Overwinter Succulents

These four ways to overwinter succulents give you several options, depending on how cold it gets where you live. Most varieties 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.

#1: Cover your plants

If you live where frost is occasional and lasts only a few hours (inland valleys of Southern CA), cover vulnerable, in-ground succulents with bed sheets when there’s a frost advisory for your area. Or use what nurseries do: Pellon nonwoven fabric or Agribon’s floating row cover. These are made of spun nylon, like fusible interfacing without the fusible part. It will protect about 2 to 4 degrees below freezing. For a bit of extra warmth, use C-9 Christmas light strings (the old-fashioned kind).

Ways to overwinter succulents

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. 

Also:
— Don’t peel away dry leaves attached to a succulent’s trunk or stem. They protect it from temperature extremes (cold and hot).
— Keep succulents on the dry side. Cells that are turgid are more likely to burst when the liquid within them freezes and expands.
— Move cold-sensitive succulents beneath a deck, tree or eaves. Such structures help to keep heat from dissipating and protect leaves from falling ice crystals.
— Or place pots against walls, hardscape, boulders and/or shrubs that absorb and slowly release the day’s heat. South- and west-facing exposures do this best.

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:

#2: Outdoors, Temporary Greenhouse

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

#3: Indoors, shelves with lights

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

#4: Climate-controlled greenhouse

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

Related Info on this Site:

Temporary greenhouse


Succulent FAQs, Basics

How to keep succulents happy


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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. Don’t fertilize succulents when they’re dormant (growth slows to a standstill, usually in winter).

Move potted succulents indoors when temperatures drop into the 30s. Clean the pots’ exteriors and check for pests. Keep them above 32 degrees F but not higher than 60 (cold is necessary for flowering later on). Keep a fan running to enhance air circulation, and a dehumidifier if the air is moist.

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.

Don’t set plants near heaters or furnace vents. They’ll cause the soil to dry out and your plants to desiccate.

Install grow lights. Situate indoor succulents beneath lights that stay on six hours daily. Fluorescent is fine and economical. Experts in growing succulents in gray-sky climates recommend T-5 grow lights. If your plants stretch toward light (or flatten their rosettes to expose more of their surface area), add more lights or move the plants closer to the ones you have.

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

 

No room? Go vertical. Create a “light island.” There are shelving units designed for indoor plants. Each shelf has a waterproof tray, and each unit is lit by two T5 bulbs. The lights, on timers, stay on from 7 am to 7 pm daily. 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 $12 on Amazon.

Watch for pests. Succulents in cramped conditions are at risk of mealy bugs, spider mites and other pests. At the first sign of infestation, spray with 70% Isopropyl alcohol. Isolate infested plants so pests don’t spread, and clean the surrounding area.

Related info on this site: Overwintering

 

How to keep succulents happy


 

 

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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.

A member of the Succulent Dreamers Facebook group summed it up perfectly:

How to water succulents

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]


All the info you need, all in one place:

 

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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

Related Info on this Site:

Succulent FAQs and basic info

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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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)