Ice plants (Delosperma spp.) are versatile perennial plants that bloom in bright purple-pink from late spring until the first frost in autumn. They are called ice plants because there are tiny, silvery hairs on their succulent leaves that make them shimmer in the sunshine as though they are covered with ice crystals. Ice plants are relatively easy to grow, so long as you give them the sunlight, soil, water, and food they need.
Consider using ice plants as a ground cover.
Ice plants grow to a height of 3 to 6 inches and width of 1 to 2 feet, which makes them suitable for use as a ground-cover plant. They thrive in the dry, gravelly soil of desert landscapes and rock gardens.
They can be planted in a landscape with any other plants that thrive in dry, gravelly soil like cactus and agave.
Edge your garden with ice plants.
Their short height also makes them useful as an edger plant or plant that grows along the edge of a landscaped area.
Plant ice plants in window boxes.
There are trailing types of ice plants with stems that grow to a height of only 1 to 2 inches then hang down, growing to a length of 9 to 18 inches. They are ideal for window boxes and containers on the patio or deck.
“Starburst” (Delosperma floribundum “Starburst”) is a popular trailing cultivar. Its flowers have a white center with purple petals.
“Basutoland” (Delosperma nubigenum “Basutoland”) is a yellow-flowering trailing ice plant.
Consider your climate when planting ice plants.
Ice plants are hardy in USDA Hardiness Zones 6 to 10 and can withstand average winter lows down to −10 °F (−23 °C).
Make sure your soil drains well.
The garden soil must be gravelly, loamy, sandy-loam or sandy. Loam is soil that is loose and crumbly. Ice plants will not thrive in clay soil due to the fact that clay soil does not drain quickly.
If your soil is clay, build a raised bed and fill it with sandy-loam soil for the ice plants or grow them in containers. Use sandy-loam soil or a potting mix formulated for cacti when growing ice plants in containers or raised beds. Sandy-loam soil is readily available in 10 or 20 pound bags at most garden centers.
Watch out for signs of rot.
If the soil does not drain quickly enough, the ice plant’s roots will rot, the leaves will turn yellow and drop and the entire plant will eventually die. If the leaves begin to turn yellow, carefully dig up the ice plant and check the roots.
If most of them are brown or black and mushy, the plant will not recover and should be thrown away.
If most of them are white, firm and healthy-looking, trim off the bad roots with sharp scissors and replant it. Let the soil dry out before watering the ice plant again. Root rot is the only disease ice plants are susceptible to but it is a very common cause of death in these plants.
Pick out a location where your ice plant will get at least six hours of sunlight each day.
Eight to ten hours of sunlight is even better. Plant them in a sunny garden or, if they are planted in containers, set them on a sunny patio or deck.
When ice plants do not get enough sunlight the leaves will become pale and they will bloom very little, if they bloom at all.
Give ice plants space.
Space plants 16 to 24 inches apart in the garden or in a window box to give the ice plants enough room to reach their mature width.
A 10- to 12-inch diameter round or square container will comfortably hold one ice plant.
Water the ice plants generously immediately after planting them.
This helps to remove air pockets and get the soil to settle around the roots.
If there are pockets of air around the roots, they will dry out and die.
Give your ice plant about 1 inch of water each week.
Do this for the first few months after you have planted them.
Choose your watering device.
Ice plants can be watered with a watering can, a soaker hose or the sprinkler. If they are watered with a soaker hose or sprinkler, set a 1-inch deep tuna or cat food can right next to the ice plants. Shut off the sprinkler or soaker hose when the can is full of water.
Cut back on your watering regimen after the first couple of months.
These are extremely drought-tolerant plants that do not need supplemental water to survive after the first few months.
They will begin to look a little rough, however, during extended periods of drought. The leaves will turn yellow or brown and shrivel. Giving them 1 to 2 inches of water every three to four weeks during an extended dry spell will keep them looking good.
Do not give ice plants supplemental water during the winter.
They will not use it and cold, wet soil will cause their roots to rot.
Give ice plants fertilizer in the spring when they begin to grow again.
Use a balanced garden plant fertilizer with a ratio of 8-8-8 or 10-10-10.
This means 8 parts nitrogen, to 8 parts phosphorous, to 8 parts potassium (or potash).
Use 4 ounces of fertilizer per 25 square feet of garden space.
Sprinkle the fertilizer on the soil around the plants but be careful not to get any on the ice plants. It could burn the leaves and stems.
If fertilizer does get on the plants, wash it off immediately with clear water. Water the ice plants right after spreading the fertilizer to help wash it into the soil.
Look for signs of mealybugs or aphids.
Ice plants are rarely bothered by pests but aphids and mealybugs do occasionally attack them. Both of these insects are generally less than 1/8-inch long. They suck juices from the ice plants and excrete a clear, sticky liquid called honeydew on the leaves. Severe infestations cause slowed plant growth, yellow leaves that eventually drop and can eventually kill the plants.
Aphids are commonly green or red but they can be nearly any color. They have soft bodies, move slowly and rarely have wings.
Mealybugs are flat, immobile insects that are most often off-white, gray or light tan. They are called mealybugs because they have a waxy coating on their backs that looks mealy.
Use the garden hose to conquer these pests.
Both of these insects can be controlled by simply spraying them off the ice plants with a garden hose. Aphids are usually blown onto the plants by the wind and mealybugs are carried by ants. They are crushed by the water from the hose or knocked off the plant and cannot get back on by themselves.
Attach a nozzle to the garden hose and spray the ice plants with the nozzle set at medium pressure. If the water pressure is too strong, it could damage the plants.
The water will also wash off the honeydew these pests create.
Spray the ice plants every few days if the insects return.
Try using insecticidal soap.
If the infestation is severe and spraying them with the garden hose is not keeping them under control, spray the plants with insecticidal soap. Insecticidal soap works by smothering aphids and mealybugs when they are sprayed.
Commercially formulated insecticidal soap works well as it is more refined but mild dish soap mixed with water will also work.
Create an insecticidal soap mixture.
Commercially formulated insecticidal soap is available in concentrated and ready-to-use formulas. Concentrated forms should be mixed with water at a rate of 5 tablespoons per gallon.
Mix it thoroughly and pour it into a spray bottle.
Use the same amount of mild dish soap in water, if you prefer, but do not use dishwasher soap, laundry soap or dish soap that is highly concentrated. Those types of soaps will damage the leaves of the ice plants.
Spray the ice plants in the morning or evening until the insecticidal soap is dripping from the leaves.
Make sure the stems, undersides of the leaves and tops of the leaves are coated. Do not spray them in the afternoon when the sunlight is strongest or when temperatures rise above 85 °F (29 °C).
The heat and strong sunlight will make the soap dry too quickly and could cause damage to the leaves.
Wait one to two hours, then wash the soap off the ice plants with plain water.
The soap will only kill aphids and mealybugs that are already on the ice plants and, if left on the plants, it could damage the leaves.
Repeat the treatment once each week if these insects continue to attack the ice plants.