By Matt Gibson
During the summer months, ice plants are decorated with yellow, purple, or pink blooms reminiscent of daisies. When the flowers fade, the low-growing, six to eight inch tall plant retains its ornamental value with its interesting succulent-like foliage. Ice plant gets its name from the tiny, shimmering dots that appear on its leaves which resemble ice crystals. Once established, the ice plant is one of the easiest plants in the garden to care for.
Though ice plant is rarely cultivated for consumption in the United States, in its native Africa, it has a long history of culinary and medicinal use. The leaves and stems can be eaten raw or cooked similar to spinach. The flavor is described as tart, acidic, and slightly salty. The leaves can also be pickled or used as a garnish, and the whole plant can be consumed as a cereal. Medicinally, ice plant has been used to treat tuberculosis, cardiovascular problems, minor skin conditions, mouth sores, constipation, and more.
Ice plant is also commonly called fig marigold, frost plant, diamond plant, dew plant, diamond ficoides, glacier lettuce, and sour fig. It is also referred to as highway plant in some regions, due to its frequent placement alongside highways, where it is planted to help reduce erosion issues.
Varieties of Ice Plant
There are many different varieties of ice plant to choose from, with a wide range of colors and foliage types. Picking out which cultivars of ice plants are right for your garden can prove challenging. To make your decision a bit easier, we have gathered some of the best cultivars here to narrow the field a little. Here is our short-list:
Orange Ice Plant – This spring blooming variety produces bright orange blooms with yellow centers and has deep-green leaves.
Redflush Ice Plant – This ice plant cultivar is slightly frost tolerant. It displays bright red flowers that seem to last all season.
Purple Vygie – The purple vygie is known for its blue-green foliage and its pink or purple flowers.
Trailing Ice Plant – A voracious spreader, the trailing ice plant can easily become invasive if not contained by strong borders. Produces white, pink, and purple flowers.
Tresco Cultivars (Orange, Red, Purple) – The tresco cultivars are a series of hybrid ice plant species that were created at the Tresco Abbey Garden on the Isles Of Scilly. These lovely ice plant cultivars are distinguished by their gray-green foliage and voluminous blooms.
Growing Conditions for Ice Plant
Ice plants are hardy to USDA zones five through nine. Outside of these zones, it can be grown as an annual or brought indoors as a houseplant. Every variety of ice plant will grow more voraciously and bloom more prolifically when grown in full sun locations. The plant’s summer flowers, which open in the morning and close after sundown, will open more fully in sunny conditions. Plenty of sun exposure will also help keep the plant from drooping and becoming leggy.
The best soil to grow ice plants in is a sandy or gravelly soil medium that is well draining and as close to a neutral pH as possible. Ice plants will grow well in most well-draining mediums, even if the soil is depleted and low in nutrients. Ice plants will not tolerate standing water, and will rot and die if left in standing water for long periods. Ice plants will not grow well in clay-based soils for this reason, unless they are amended with lots of organic material and sand to improve drainage.
Don’t let their name fool you, as ice plants are not fond of cold weather, nor will they survive in prolonged frosts. Most cultivars will only grow well in warm climates, though the hardiness does vary somewhat between species. A few species can tolerate minor frosts, but if you live in a cold climate area, it is better to grow ice plants as annuals or to bring them indoors to decorate your home. Ice plants are also quite fond of dry growing conditions and will suffer from overly damp or humid conditions. Prolonged exposure to humidity can lead to rot.
How to Plant Ice Plant
The recommended way to grow ice plants is to start seeds indoors and transplant seedlings into the garden after the threat of frost has passed. Using a small container for seed starting tray and a seed-starting soil formula, sow ice plant seeds four to six weeks prior to the last frost. Lightly press seeds into the soil but avoid covering completely, as seeds require light to germinate. Keep the container or tray moist until germination, which should occur within 15 to 20 days.
As soon as seedlings begin to emerge, place the container or tray on a sunny windowsill. If you don’t have a very sunny indoor spot to place your ice plant seedlings in, you may need to use fluorescent plant lights. Keep seedlings three to four inches under lights and run lights 16 hours per day, resting for eight hours in the night time. Plants require darkness to grow, so don’t forget to give your ice plants a significant dark period each day. As plants grow taller, raise lights up to keep them at a distance of three to four inches above plants. Do not use incandescent bulbs, as they get far too hot and can burn your plants.
Feed seedlings once when they are three to four weeks old with a starter solution. Starter solutions are typically a half strength dose of what is given to mature indoor houseplants. Before planting in the garden, harden your seedlings off by gradually exposing them to outdoor conditions, increasing the exposure time a bit each day. Be sure to protect young plants from high winds and extremely hot sun while hardening them off. Gradually exposing your plants to the outdoors will increase their cell structure and reduce the chances of transplant shock.
Prior to transplanting, prepare the beds by tilling the soil to a depth of six to 12 inches, removing any rocks, clumps, or plant debris in the process. Choose a full-sun location with sandy, well-draining soil, and transplant your seedlings on a cloudy day or in the late afternoon to reduce the chance of transplant shock. Space plants 18 inches apart and water thoroughly just after planting. Lay out a light, one to two-inch layer of mulch around your seedlings to deter weeds and improve moisture retention.
Care for Ice Plant
Once ice plants are established, there is very little care required for them to thrive. Though ice plants are extremely drought tolerant, they can still benefit from regular waterings in times of prolonged heat and drought. Water ice plants once per week when rainfall is minimal. Potted ice plants may require additional watering. Allow the top two inches of soil to dry out between waterings during the summer when the plants are in dormancy.
Though fertilizers are not necessary for ice-plants grown in the ground, it may be an answer to minimal blooming issues. Plants grown in containers are quick to deplete their nutrients and could benefit from an occasional boost from a balanced fertilizer.
How to Propagate Ice Plant
Though ice plants can be propagated by seed, cuttings, and division, cuttings are the recommended propagation method, as it is the fastest and easiest way to make more ice plants. Take your cuttings when the plant is quickly growing between spring and autumn. Take three to six inch pieces of shoot and remove all leaves other than the topmost set. Allow the cuttings to dry and form calluses from exposing them to several hours of air overnight. Root your cuttings in a well-draining container using a succulent potting mix. Keep the substrate moist until your cuttings start to root. Gently tugging on the cuttings will let you know whether roots have formed or not. If the tugging is met with resistance, it means the roots have formed and the plant is ready to be moved into a larger container or into the ground during the spring.
Garden Pests and Diseases of Ice Plant
Damp conditions, cold spells, and other weather issues are typically the most pressing problems to cultivating ice plants. Overly moist soil conditions can cause fungal infections that can kill your plants, including botrytis, damping off, root rot, and sooty mold. Aphids, mealybugs, and scale pests can sometimes trouble ice plants, though providing a healthy growing environment will likely keep your plants healthy enough to ward off these pests.
If you need a low-growing carpet of succulent-like foliage and lots of colorful, daisy-like flowers throughout the summer, ice plant is the plant for you. Ice plants will also help control erosion and strengthen the soil structure wherever it is planted.