For over 40 years, Panayoti Kelaidis has served as a curator and director of outreach at the Denver Botanic Gardens. Photo courtesy of Panayoti Kelaidis

by Enrico Villamaino

For a very long time, landscape architects in the American West had to use what Panayoti Kelaidis dubbed “hand-me-down horticulture.”

Kelaidis, senior curator and director of outreach for the Denver Botanic Gardens, elaborated during his presentation “Reinventing a Western Landscape Aesthetic” at the Perennial Plant Association’s 2021 National Symposium.

“The West is a very vast area,” Kelaidis began. “We’re talking about quite a range of habitats. There are valleys, mountains and extremities of the seasons. This expanse covers the Great Plains to the Pacific Ocean; from Mexico to Canada.”

He said that the American West is truly a “glorious landscape,” with a large percentage of the biodiversity endemic to American plant life found in the Rocky Mountain region alone. Nevertheless, the region was settled more by miners than gardeners. As a result, much of what was planted and cultivated was more Connecticut than Colorado. “Most of what was originally used in landscape architecture was the same old, same old. People just used what they had seen being used on the East Coast. It was not a great palette.”

That palette, according to Kelaidis, consisted of four main elements: turf, spreaders, uprights and trees. He explained, “More often than not, the turf would be bluegrass. The spreaders would be pfitzers; for uprights they favored junipers; and blue spruce was the tree of choice. It was all very routine.” He added that the more adventurous planters would add posies.

All of this changed in the latter half of the 20th century. Homeowners began to adorn their properties with cacti and succulents. Kelaidis himself made numerous trips to, of all places, South Africa in search of new species for the Western landscape. “Many people are surprised when they first hear this. They think of Africa as exceedingly hot and the snow-capped mountains in the West as snow-covered. What they don’t realize is that much of the plant life from higher elevations in Africa have transplanted very nicely here.”

In particular, Kelaidis pointed to several species that have thrived in the U.S., and have proven very popular with consumers.

The Delosperma nubigenum, commonly called ice plant, is a succulent, mat-forming species that reportedly has formidable winter hardiness. It typically grows to only two inches tall but spreads to 20 inches wide. Foliage is covered with small but bright yellow flowers from late spring to early autumn, acquiring a reddish hue later in that season. Kelaidis pointed out that this is a very common choice for step gardens.

D. cooperi forms a vigorous, succulent, spreading evergreen ground cover. However, outside of USDA Zone 7 (which stretches from Arizona in the south northward through regions into Washington) it is at best semi-evergreen and is not reliably winter hardy. This succulent mat-forming plant typically grows to three inches tall and spreads quickly to 24 inches or more. Daisy-like, bright red-purple flowers of up to two inches across cover the plant with bloom from June to September. The neon-like intensity of the flower color and length of bloom greatly enhance the ornamental interest of these plants. He added that this species is best grown in dry, well-drained soils in full sun. It will grow poorly or die in any soil that is not well-drained.

The D. floribundum Starburst® variety is also mat-forming succulent. It grows to only four inches tall but spreads to 10 to 18 inches wide, with foliage covered with transparent flakes that resemble small pieces of ice. Its petals shimmer as if they were covered with thin metal. Kelaidis said that while its bloom is short, it is breathtaking.

It’s only reasonable to assume that in transplanting African plants in the U.S., the development of new hybrids was inevitable. One of the most popular is the Delosperma Red Mountain Flame®. With flowers nearly three inches across, Kelaidis described its color as “a brilliant scarlet. It is very popular.”

Another hybrid that has a place close to Kelaidis’s heart is the species named for him. The D. ‘Kelaidis’ emerged as a spontaneous hybrid seedling in Denver. Its flowers are a delicate pink. “To be honest,” Kelaidis laughed, “I would have preferred something with a robust red flower. But it’s an honor nonetheless and I love it.”

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