Succulents in the genus Crassula are native to South Africa. They include shrub (branching) varieties commonly called jade plants, as well as "stacked crassulas" with leaves pancaked along thin stems. Green jade (Crassula ovata) is a common houseplant worldwide. Nearly any nursery sells it, and it's often added to assortments or used as a giveaway plant. Newer cultivars are more interesting, just as easy to grow and well worth having. Look for those with rippled or tubular leaves; diminutive varieties; and those variegated with gold, yellow, cream, pink or red.
Crassulas prefer mild, frost-free regions with low humidity (but not desert heat) typical of Southern California from the Bay Area south. The thicker the stem, the more drought-resistent the plant. Although jades appreciate regular water, they're often the last plants standing in neglected gardens---an indication of their ability to do without. Leaves shrivel as plants draw on stored moisture, then plump when rains return.
Like aloes, many crassulas will stress beautifully to shades of red, yellow and orange. Sun makes the difference. In low light, even the reddest jades will revert to green.
Pests seldom are a problem. The biggest challenge with these simple succulents is protecting them from temperatures below 32 degrees F.
Plants that prune themselves
A remarkable thing about jades is that random limbs will shrivel and fall off. This enhances air circulation, allows more sunlight to enter, and starts new little plants. Eventually you get a sort of bonsai---a nicely balanced shrub that resembles a small tree. This is most noticeable in old potted specimens with thick trunks. Remove any baby plants if you don't want them.
It's obvious how to take stem cuttings from shrub crassulas: Cut off the top few inches and stick it upright in the ground; as with most succulents, new roots will grow where old leaves were attached. But how about stacked crassulas? It's basically the same, except you gently remove the lowest leaves. One stem can yield a dozen cuttings! See my video: How to Propagate Stacked Crassulas.
Where to buy crassulas
Debra Defends Jade Plant (4:04) Some have tubular leaves, others are yellow, red or variegated...
Plant a Pink Jade Succulent Container (3:02) Debra combines pink-flowering jade with Echeveria agavoides 'Lipstick'...
Grow Sunset Jade! (0:50) See a slope planted with golden variegated jade in midwinter, in full bloom...
How to Propagate Stacked Crassulas (3:53) You'll be amazed by how many new little plants you can get from an 8-inch stem!
Crassula Photo Gallery
Because varieties can look quite different depending on growing conditions and when flowering, you may see several photos with the same ID. If a plant is mostly green, it was likely in bright shade; if red, orange and/or yellow, in full to half-day sun.
I'm confident these names are correct, but if you believe I've made an error, do let me know. Thanks! — Debra Lee Baldwin