I Scream, You Scream, We All Scream for Ice Plants!

One of my favorite waterwise plants in the garden! Cold hardy Ice Plants (Delosperma) are one of the most versatile plants that I love to use in my USDA zone 5b garden. Not only do they put on an extraordinary show, they are one of the best “weed fabrics” aka groundcovers out there! They only grow 1-4 inches tall and will generally continue to spread slowly but are easily pulled. One of the best parts is they are pretty low water compared to your lawn but on the contrary, you can’t walk on them either. In this post I’ll line up the what, when, and where to to use Ice Plants and then we’ll review some of my favorite cold hardy Ice Plants on the market.

What is an Ice Plant (Delosperma)?

This South African native succulent is found in the mid to high elevations of the mountains and deserts in its native range. It gets it’s name from the fact the succulent leaves very close up look like they are slightly frosted and depending on light have a slight shimmer. Ice plants are a clumping mat forming perennials that can withstand freezing temperatures, unlike the version of Ice Plants (Carpobrotus) that people from California are familiar with. The Ice Plants (Delosperma) is also nowhere near as invasive as it’s Carpobrotus cousin.

Here in Colorado and the lower intermountain regions, Ice Plant (Delosperma) particularly loves dry hot conditions. During the winter most varieties will turn a purple color with some winter die back until spring. Ice Plants do not like wet winter conditions or places where it will be covered by snow all winter long. Once warmer weather has returned Ice Plants will turn green again and begin to continue to spread and bloom prolifically . Below is an example of my Raspberry Granita Ice Plant in late May growing along a southwest facing retaining wall. As you can see it really loves spreading along the hot warm concrete wall.

When Should You Plant Ice Plant?

Since Ice Plant is hardy you can plant them anytime during the growing season. However, I depending on the location I would try to avoid late fall if it is in a partial shaded location or in an area where it is likely to be covered by snow more often than not. I personally like to plant my ice plants early in growing season which is in May where I am located in USDA zone 5b. Ice plants are also really easy to propagate from cuttings from the main plant. If I am taking a small cutting (smaller than a handful), I will generally do that in May/early June or sometime in early September.

To establish Ice Plants, I will generally water them twice to once a week the first couple of weeks. Once established after a few weeks depending on your soil, you can generally cut it down to about once every other week depending on rainfall and soil conditions. Since large rocks, edges of patio/driveway/sidewalks, and retainment walls hold excess moisture underneath them, I find that Ice Plants do exceptionally well next to them. Avoid areas with high moisture like next to an irrigated lawn as this is a succulent plant that likes to dry out between watering. Below is a 1 year old ice plant late in early October after blooming. In about one year it has spread around two feet between the steps and small moss rocks.

Where Should You Place an Ice Plant?

Ice Plants are a full sun heat loving succulent. Depending on the variety, they can grown between USDA zone 4 – 9. Here in Castle Rock, CO, I live at 6400ft+ and normally place them near a large rock or southern or west facing wall to help melt the snow quicker. I find during the growing season Ice Plants will generally grow anywhere in USDA zone 5b aside from an area in wet conditions or full shade. Ice Plants can be grown in partial shade but will not have as much vigor. It can also prove problematic during the winter months and it might be better off to be treated as an annual in part sun conditions, unless only being blocked by a deciduous trees. However, full sun is best for maximum flowering and growth.

As previously mentioned, I prefer Ice Plants next to large rock structures and along the garden boarder. Below is an another example of Ice Plants growing next to larger rock and siloam stone steps. The goal here is to have the Ice Plants fill in completely around the stone steps. The other purpose is that these are planted on about a 15-20 degree slope that in the past would get severe erosion during have downpours. Since they form a large mat and have an extensive root structure, these plants make for an exceptional erosion control plant in the garden that doesn’t require much water. They not only hold the soil in place, but they also help slow down the water runoff with their dense low formed mat.

Another spot I like to use Ice Plants is to fill in blank spots in the garden. These mat forming plants are excellent at keeping weeds to a minimum. I do find that the occasional dandelion or thistle will weasel its way in. Generally I find the roots of any weeds that did make it are very shallow and not well established due to the how the Ice Plant forms it’s mat. Since Ice Plants are such a low growing perennial they do great between plants like the Mountain Sun Daisy, Yarrows, or Grasses. Since they do not like shade, they have a hard time smothering other plants in the garden. However, if your plants are short or leggy, they could have a battle royale with each other. Below is an example of Ice Plants growing next to Mountain Sun Daisy and again another stone pathway. Since Mountain Sun Daisy are pretty vigorous spreaders themselves, I try to plant the two, about 24-30 inches part from each other. In about one year they’ll form a harmonious solid mat as shown.