Aloe leaf cut open (c) Debra Lee Baldwin

What Makes Succulents SUCCULENT?

What Makes Succulents SUCCULENT? In my new video of the same name, I rank common succulents 1-to-10 on a "Juiciness Scale." Slicing and squishing may seem unkind, but there's method to my madness. Become a better plant parent by learning the "how's" and "why's" of these lovable chubby plants. On this page you'll discover the fascinating Science of Succulence: how leaves, skin, roots and more make succulents, well, succulent---as well as astonishingly efficient.

The Science of Succulence

Succulents come from climates with low rainfall, strong sun and low humidity. In regions where thin-leaved plants would quickly shrivel, succulents survive---even thrive. The key is the quality of succulence: juicy, moisture-filled leaves that the plants draw on during hot, dry spells. Depending on the time of year and the variety, a succulent's moisture content may be as high as 95%.

Smart leaves

Glottiphyllum leaf squished (c) Debra Lee Baldwin

Glottiphyllum linguiforme (from the video)

Succulent leaf cells expand during rainy weather and shrink during drought. Certain varieties such as aloes also contain a gelatinous goo (mucilage). Although thick leaves mean less light reaches the plant for photosynthesis (chlorophyll + sunlight = energy for growth), that's OK because succulents are from climates with few cloudy days. In fact, some succulents further shade themselves with spines or filaments, or have a powdery coating that deflects UV light.

Waxy skin

The thick, waxy skin of succulents has comparatively few surface openings (stomata) that enable gas exchange (transpiration) with surrounding air. This minimizes evaporation and ties in with crassulacean acid metabolism (CAM), which makes succulents---in particular elephant's food (Portulacaria afra)---renowned for their ability to scrub harmful carbon from the atmosphere. Learn more.

The role of roots

Generally a tap root anchors a succulent, and it sends delicate roots laterally just below the soil surface. These shallow roots absorb even small amounts of rain and irrigation. Roots of succulents may contract during dry spells to avoid desiccation, then regrow when rains return.

Regional adaptations 

Succulents are nothing if not smart! The way they deal with hostile environments is amazing. Here are two examples.

Saguaro cactus (c) Debra Lee Baldwin

Yours Truly with a saguaro cactus in Tucson

Ribbed cacti of the desert Southwest expand during seasonal rains, then gradually shrink during periods of intense sun, high heat and low humidity. Such moisture depletion deepens surface "valleys," serving to shade the plant and lessen its exposure to the elements.

Lithops (c) Debra Lee Baldwin

Lithops have patches of translucent tissue

In arid regions of Africa, certain small succulents have translucent tissue at their leaf tips. These dots, fissures or windows let sunlight enter plump plants that are buried up to their necks to avoid being eaten or sun-scorched. “Living stones” such as lithops as well as certain haworthias come to mind, but my favorite is Fenestraria (baby toes)---partly because the Latin name means “windows.”

Fenestraria aurantiaca (c) Debra Lee Baldwin

Fenestraria aurantiaca (baby toes) has windowed tips

Related info on this site 

Portulacaria afra in ground (c) Debra Lee Baldwin

How Succulents Combat Global Warming

When you grow succulents in your garden, you’re helping combat global warming.  The plants are especially efficient at scrubbing carbon dioxide from the atmosphere.  It has to do with

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Succulents stop fire (c) Debra Lee Baldwin

How Succulents Protected a Home from Wildfire

Such reports aren’t unprecedented. Suzy Schaefer’s succulent garden in Rancho Santa Fe “saved our home,” she told me (and national media) after the Witch Creek Fire. I had heard of others as well. Even so, I was skeptical. True, succulents tend to cook rather than burn and don’t transmit flames. But wildfire is so intense it melts metal…

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6 Comments

  1. Matthew Midgett on March 11, 2021 at 12:13 pm

    Wow! Your articles are educational AND entertaining. It’s difficult (and wrong) to take succulents for granted, when you provide such interesting information about them. Thanks!

    • Debra Lee Baldwin on March 11, 2021 at 12:46 pm

      Aw, Matt, you’re such a love! And YOU have the BEST blog on exploring New Mexico on horseback. I’ll never forget meeting and interviewing you for Sunset back in the ’90s at your marvelous adobe ranch home near San Diego, with its retro (mid-century) succulent garden.

      • Steve on March 12, 2021 at 10:59 am

        Excellent article! Short and to the point and with great photos.

        • Debra Lee Baldwin on March 12, 2021 at 3:18 pm

          Thank you Steve!

  2. Isabel Bloom on March 12, 2021 at 3:12 pm

    You are a wealth of information on succulents and cacti and a talented photographer! Although you had help with the photo of you and the saguaro, it is a beautiful shot! I wonder if the saguaro is photo bombing you or are you photo bombing the saguaro?! 🙂

    • Debra Lee Baldwin on March 12, 2021 at 3:21 pm

      Thanks, Isabel! I’m the worst subject for photos because I’m never satisfied. “Here, take it again,” I say to my husband after looking at a shot he just took. “Only this time I want my hair backlit, don’t shoot straight up my nose, and try to get my left profile, OK? Oh! And zoom in more, but be sure you include (yada, yada).” Poor man, he actually winces when I ask him to take my photo.

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