Growing Aeoniums In Phoenix Arizona

Article contributed by: Grant Meyer 
Photo
Shown on the right is a small sampling of the many cultivars of Aeoniums available. They are available in a wide range of plant and leaf sizes, plus leaf coloration (light green, dark green, burgundy, variegated and combinations... great for the collector). Some aeoniums have rosettes of foliage with a diameter of just 2 inches (5 centimeters) and others have individual rosettes that are easily a foot across (30 centimeters). The colorful plant on the upper left is a Kiwi, and the black one on the upper right is a Schwarzkopf. The Schwarzkopf is 5 years old. A tennis ball has been included to give a sense of scale.
Aeonium - Several Varieties
Overview
Aeoniums are originally from the islands off the North coast of Africa and are generally winter-growing and summer-dormant. Despite what many "experts" say, Aeoniums will do quite well in the Phoenix metro as long as you select suitable varieties (non tropical types) and as long as you give them plenty of sun in winter, and light shade (and less water) in summer.

Heat Tolerance and Sun Exposure
In the Phoenix metro, aeoniums thrive in partial to full sun from autumn through spring (say, November through April or so). Once the blast furnace kicks in for summer, they prefer partial shade to full bright shade. Aeoniums are ideal for containers which can be relocated through the seasons to adjust to these needs, and are relatively good candidates for growing in the ground under deciduous trees where they get winter sun and summer shade.

Cold Tolerance
Cold tolerance varies greatly with variety, so it is good to do some research before choosing one. Typically aeoniums are fine to 28 degrees F ( -2 C), but the more tropical types (generally with large, floppy leaves) will want to be kept warmer. I've grown the dark-leaf variety 'Schwartzkopf' outside in outer North Scottsdale for five years with no damage from cold. They're certainly are happier in warmer winters, but many are fairly cold tolerant (for here). None will tolerate a long, hard freeze, so bring them indoors for a day or two if you expect such conditions.

Planting
I grow my aeoniums in basic cactus/succulent mix, which for me is about one part regular houseplant potting soil, one part pumice, and one part coarse sand. I generally grow them in porous terracotta pots. If planted in the ground, again make sure they get winter sun and summer shade, and keep them in a fast-draining location.

Fertilizing, Watering, and Growth Rate
One key aspect of culture to remember is that aeoniums grow actively during the cooler months, generally November through May or June, so those are the months to water and fertilize them regularly. Even though watering is more frequent, it is still important to let them dry out between waterings. During these active months, water once a week and fertilize once a month with a basic water-soluble house plant fertilizer, or water-soluble tomato plant fertilizer.

Now for the tricky part. In summer, when it's the hottest, aeoniums enter dormancy and require very little water. Watering frequency drops to approximately every two weeks. Over watering aeoniums in summer is their number one killer. Do not fertilize them during this time. When they are dormant in summer, they are not the most beautiful plants and will drop many of their lower leaves and the rosettes of foliage often curve in on themselves to create shade. They can look a bit like Brussels sprouts on long stems. But rest assured, as temperatures cool down, they will relax and begin active, vigorous growth again.

Propagation
Aeoniums are very easy to propagate from stem cuttings in late winter and early spring. Just snap or cut a rosette of leaves off with an inch (or two, or three, or six) of stem attached. Remove any lower leaves and let the cutting air-dry in the shade for two days and plant in the same mix as the adults. Water well and water on the same schedule as the adult plants. They root quickly and easily, but again, only during their active growth during the cool months. Cuttings in summer almost always rot and those in winter usually are slow to start due to low temps and short days.

Pests
Aeoniums are relatively pest-free. They can be attacked by the usual suspects like scale or aphids, or mealy bugs, but these are easily treated with your method of choice. Some alternatives are: 70% rubbing alcohol rubbed on the insects, insecticidal soap, and systemic insecticide. My aeoniums have yet to be bothered by any pests.