Summer 2024

Why some Stress might be Good for your Succulents

by Hedwig Van Den Broeck

Research shows that having a positive attitude towards stress in our lives may help us grow and perform better. It is the course of Nature and happens in our gardens as well. In this article, we’d like to address the amazing color changes in outdoor growing succulents that produce more beautiful and vibrant colors when exposed to stressful conditions. We are not writing about their amazing flowers but rather about the color change in the leaves and stems of succulents.
Stress might sound dramatic, but, no worries, you won’t harm your succulents. You are simply manipulating the succulents' ability to survive harsher conditions. Like all plants, succulents require just the right amounts of water and sunlight to thrive.
While buying your favorite succulents at the nursery, you were probably blown away by their amazing colors. You took them home, pampered them, and then, after a short period of time, you might have become dismayed that they turned green! What happened to the vibrant pinks, oranges, purples, and blues?

Succulents are native to many arid areas all over the world, including California. So don’t treat them too well! Learning how to reduce or change a few factors encourages color change because succulents perform best within their natural temperature range. Like many Mediterranean-climate plants, succulents have characteristics that enable them to defend themselves against hot, dry summers and poor soil conditions. Succulents do need a bit of stress to showcase more color in their leaves, stems, and blooms.

A little science is in order here. Two pigments are responsible for the bright colors in succulents: anthocyanins and carotenoids. Anthocyanins produce red, purple, or blue hues, while carotenoids create yellow and orange tones. These pigments act as natural sunscreens, protecting the plants from excessive sunlight and UV radiation.
These pigments appear when a succulent is stressed or in a state of dormancy — also known as being drought-deciduous. These pigments mask the more common, green-colored chlorophyll, turning the plant into other, more appealing shades. And that’s where the magic starts!

In addition, the metabolism of many succulents differs from that of other plants, which breathe through stomata (pores) that open during the day. Succulents, however, have a reduced number of stomata on their leaves. Succulents can conserve water during the hottest part of the day because these stomata only open at night.

Brian Kemble, curator of the Ruth Bancroft Gardens in Walnut Creek, mentioned that healthy color changes in succulents can be attributed to either seasonal changes or exposure to sunlight (or lack thereof.) In agaves, color change can also happen when the plant is nearing the end of its life and might be devoting all of its energy into producing one final spectacular bloom.

What are the stressors?

Sunlight

Succulents are known for their unique shapes and water-storing capabilities. Not only are they easy to grow and propagate, they can also surprise us with stunning colors which range from the vivid greens of a shaded jade plant to the dazzling reds of an Echeveria under stress from the sun.

Some succulents become more pigmented in the presence of strong sunshine, producing darker shades of red, purple, or orange in their leaves and stems. This adaptation not only allows them to endure harsher environments but also produces an amazing visual show for us to enjoy.
On the other hand, succulents housed in lower light levels could turn back to green. This is because when they are not exposed to as much sunshine, they create less carotenoid and anthocyanin pigments, and the green chlorophyll becomes the dominant color.

Water and Temperature
are important factors in succulent color as well. Too much or too little water can have an impact on pigment production, and cooler temperatures can intensify color in certain succulents.

Soil
Succulents need good drainage to thrive. What soil to use will depend on whether you are planting in-ground, in raised beds, or in pots. Potted succulents tend to get stressed more easily, especially when the soil has not been refreshed for over 2 years. For more information on the correct soil to use, watch our webinar: The Joy of Succulents on our YouTube channel.

We can influence the color expression of our succulents through our sustainable practices. Choosing the right soil, adjusting light exposure, and following correct watering routines can encourage succulents to show off their true colors.

Each type of succulent has its own color scheme and reaction to environmental signals. We encourage you to read up on the growing conditions of your succulents, as some react positively to harsher conditions while others do not.

Succulent dormancy also needs to be taken into consideration. Some summer dormant plants, like Dudleya and Aloe, can get pretty rough looking during the summer. We included a selective list of dormancy for some of the more popular succulents.

While we continue to care for our precious plants, let's marvel at the color changes our outdoor growing succulents go through. Whether they are thriving in the sun or enduring a drought, these plants serve as a constant reminder of the strength and beauty of the natural world.

Additional Information:

Dormancy:
Some popular Summer dormant succulents are: Adromischus, Aeonium, Aloe, Anacampseros, Cotyledon, Crassula, Graptopetalum, Gasteria, Graptoveria Haworthia, Kalanchoe, Pachyveria, Pachyphylum, Sedeveria, Sedum, Senecio

Some Winter dormant succulents are: Agave, Echeveria, Euphorbia, Lithops, Sempervivum, Tilandsia

References:

The Joy of Succulents webinar (UC Master Gardener Program of Contra Costa County)
https://www.youtube.com/watch?v=cH5NyV5LBdM&t=6s

California Native Succulents listed on Calscape

Succulents (UC Master Gardener Program of Sonoma County)
https://sonomamg.ucanr.edu/Recommended_Plants_for_Sonoma_County/Succulents/

Success with Sensational Succulents (UC Master Gardener Program of Marin County)
https://marinmg.ucanr.edu/ASK_US/IJ_ARCHIVE/?uid=921&ds=275

Book: Succulent Plants of the World, by Fred Dortort

The Biological Principle of How Succulents Change Color
https://www.springergarden.com/blogs/blog/the-biological-principle-of-how-succulents-change-color

How to Make Succulents Turn Color
https://thesucculenteclectic.com/how-to-make-succulents-change-color/

The Secret to Colorful Succulents
https://thesucculenteclectic.com/secret-to-colorful-succulents-stress/

Are Your Succulents Well Stressed?
https://debraleebaldwin.com/succulent-how-to/stress-succulents/

How to Stress Succulents and Why (YouTube video)
https://www.youtube.com/watch?v=665_dhC9kyw