Yardsmart: Raising succulents requires new way of thinking

Succulent plants live by their own rules. To really understand their preferences I had to throw out what I know about traditional gardening and start again. Now that these plants are finding their way to every corner of America, those who have fallen in love with their beauty and easy care will have to rethink the rules as well.

If you study cactus and succulents in the wild as I do here in the southern California desert, simple observation reveals many things. These plants tend to occur on well-drained rocky, south facing slopes. They perch in nooks and crannies where there is little to no soil. The roots survive in crevices that reach deep into the cliff where rock has trapped moisture year around.

Walk through the desert and you'll find plants springing out from beneath rocks and boulders. Here the ground is sandy gravel and porous, so the plants send their roots beneath the rock where it's cool and moist. Sure, they root out into the open to catch scant rainfall, but it moves so quickly through the granular ground that it's difficult to capture. The rain will soak the ground beneath the rocks where it remains long after skies have cleared so roots have more time to take it up.

Soil beneath rocks is also more stable. In the desert sudden rainfall causes enormous erosion, carrying sand far and wide along dry washes and drainages. Plants that depend on this soil for stability will be washed out unless they find anchorage beneath a rock or boulder.

The natural model is also why I like to use at least one decorative stone when I plant young succulents in pots. It's hard to apply water without its velocity picking up particles as it hits the potting soil. This causes the soil levels to drop on the watered side and the traveling particles build up on the other side. It's doubly problematic when your plants have limited access.

Soil movement is more prevalent in pots containing very young succulents and cacti. It's my practice to find a beautifully complementary "watering" rock to go into the pot of every youngster. When I water, I pour it onto the rock, and from there the water flows naturally into the surrounding soil. There is no high velocity flow applied to the soil so there is no erosion, and I can be sure there is plenty of moisture beneath the stone.

Watering inevitably brings the white perlite and woody matter in the potting soil to the surface where it floats. This is reduced by using a fine gravel mulch layer on top, which is far more than decorative, but actually mimics the layers of soil laid down in the desert from rain events. When you water your rock, it flows down into the gravel mulch so the root zone remains undisturbed.

You might be surprised to discover that your succulents tend to send out pups on the far side of the stone. This demonstrates how well they root beneath it and why they prefer to put out new growth points around its edges. Over time many succulents will flesh out the ground around the stone to create a truly eye-catching adult. For plants such as cacti that demand more space as they grow larger, the rock can be removed to allow for development. By that time the roots will be dense enough to hold the entire soil mass tightly.

Ever since I began using watering rocks, I've become a rock hound, collecting unique colors, shapes and sizes that work with my plants. Every hike, every trip to the beach or every visit to my favorite stone yard yields great finds. For high-end creations, don't overlook specialty minerals that can turn a $2 succulent into a big-bucks specimen in just the right pot.

Maureen Gilmer is an author, horticulturist and landscape designer. Learn more at www.MoPlants.com. Contact her at mogilmer@yahoo.com or P.O. Box 891, Morongo Valley, CA 92256.