S. morganianum (burro's or donkey's tail)

CHARACTERISTICS:   The burro's tail is a fascinating plant: its strange 1-inch-long tear-shaped leaves overlap so closely on pendant stems they seem to form 1- to 1 1/2-inch-thick braids as much as 1 1/2 feet long. The green succulent leaves are covered with a powdery blue dust, called bloom, like that found on blueberries and plums. The plants should be placed where they will be undisturbed because the leaves are attached flimsily and fall easily.

HOW TO GROW. Burro's tails do best where they get four or more hours a day of direct sunlight, or where artificial and natural light average 1,000 foot-candles over 12 hours a day, but they will grow fairly well in bright indirect light, such as that reflected from light walls. Night temperatures of 50° to 55° and day temperatures of 68° to 72° are ideal. Let the soil become moderately dry between thorough waterings from spring through fall; in winter, water only enough to keep the leaves from shriveling. Feed established plants three times a year, in very early spring, late spring and late summer; do not feed them the rest of the year and wait four to six months before feeding newly potted plants. Burro's tails rarely need repotting. Because the leaves are brittle, feed and water old, overcrowded plants more often than usual rather than repot them. If repotting is necessary, use a mixture consisting of 1 part loam, 1 part leaf mold, 1 part sharp sand and 1/2 part crushed charcoal, or else use a mixture of equal parts of a packaged general-purpose potting soil and sharp sand; to each gallon pailful of whichever of these mixtures you use, add 1 tablespoon of ground limestone and 1 tablespoon of bone meal. Propagate at any season by inserting the bottom of an entire leaf into sand. Watch for mealybugs.