Thursday, April 28, 2011

Ice plants lighting up the garden

Three years ago I planted some trailing ice plants (Delosperma cooperi) in a hot and dry spot in our front yard where previously nothing much would grow. This area is at the bottom of a slight slope which used to be dominated by a mistletoe-infested Bradford pear. This tree hogged all the water and nutrients it could, making it difficult for other plants to thrive near it.

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Delosperma cooperi bordering a sea of yellow:
Jerusalem sage (Phlomis fruticosa) at the top left,
Cape balsam (Bulbine frutescens) below it

Fortunately, this tree was removed by the City of Davis in January of 2010 and we replaced it with a giant clumping timber bamboo (Bambusa oldhamii). This area is now completely transformed. Not only is the bamboo thriving, all the other plants are as well. This includes our trailing ice plants. They have more than quadrupled in size and at the moment are lighting up this part of the planting strip with a color so intense, it almost looks unreal.

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Delosperma cooperi in full bloom
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The flowers only open up when exposed to strong sunlight. This is what they look like in the morning and evening, or on cloudy days.

Delosperma cooperi is one of many plants that go by the moniker “ice plant.” Native to South Africa, it is a drought-tolerant creeper with very small leaves—significantly smaller than the sea fig (Carpobrotus chilensis), for example. It needs full sun and well-drained soil but does tolerate a bit more water than many other ice plants. It blooms from spring to fall, although in my experience the initial burst of flowers is by far the best.

Unlike most other ice plants, Delosperma cooperi is very cold hardy, supposedly all the way to zone 5. However, the Missouri Botanical Garden says that in the St Louis area (zone 6), Delosperma cooperi is “at best semi-evergreen and is not reliably winter hardy.”

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Delosperma cooperi flowers are typically fuchsia purple, like ours. However, in recent years some hybrids have come out that have different colors. At the top of my wish list is salmon pink Delosperma ‘Kelaidis’, named after Panayoti Kelaidis, Curator of Plant Collections at the Denver Botanic Gardens where it appeared as a seedling mutation. I’m still waiting for this hybrid to make an appearance at our local nurseries; I’m sure it will eventually since it’s distributed by Monrovia under the registered trademark Mesa Verde®.

Apparently, Delosperma cooperi is easy to propagate from cuttings. I will definitely give this a try so I can spread it to different areas of our front yard planting strip.

Some interesting side notes:

In addition to Delosperma cooperi, the name “ice plant” is also used for the sea fig (Carpobrotus chilensis) commonly found along the shoreline on Central California’s Monterey Peninsula, the closely related Hottentot fig (Carpobrotus edulis), as well as many other plants in the genera Lampranthus, Drosanthemum (known as the “vygies”), and Aptenia. Confusion reigns supreme!

Many gardeners on the California coast lump all ice plants together under the moniker “mesembryanthemum.” Today, the genus Mesembryanthemum only contains a few ice plants rarely seen outside South Africa. However, in the past it also contained the ice plants so ubiquitous along the California coast, especially the invasive sea fig, Carpobrotus chilensis, which in spite of its species name is native to South Africa, not Chile. It has become such a common sight that many people—including gardening web sites—think it’s a California native. Massive efforts have been made in the last 20 years to eradicate Carpobrotus chilensis and edulis so native plants have a chance at a comeback. While ecologically sound, this hasn’t been an easy sell to the public since in a floral beauty contest Carpobrotus would beat the coastal natives any day.

2 comments:

  1. No fair mentioning mobot and St. Louis in your post! ;-)

    It's most likely not reliable here because of too much winter moisture. I know the one I planted didn't make it, but I could probably find a better location for it.

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  2. Alan, I love Mobot.org. It's a great plant resource no matter where you live.

    If you amend your soil with decomposed granite, pea gravel, etc. and plant them on a slight mound, Delosperma might make it through the winter in your garden.

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