Plant of the Month for March, 2019

 (del-oh-SPUR-muh  kon-JES-tum)

General Information:

Delosperma congestum is a cold hardy succulent that makes spectacular flowers that glisten in the sun. It is an alpine plant that originates from the mountains of South Africa.

Delosperma congestum : photo by Robert Pavlis

Delosperma congestum :photo by Robert Pavlis

The common name for Delosperma is hardy ice plant, and this species is known as the congested ice plant. The name ice plant may be due to fact that the leaves are covered with papillose tissue which reflects light, giving the leaves frost-covered look.

This plant is rated for zone 5 and is commonly found in nurseries in S. Ontario. Unfortunately, it is not a reliable plant here. In drier zone 5 areas, such as the mid-western US, this is a reliable perennial but in the wetter eastern regions of North America, it seems to die out in winter, even when grown in a fast draining sandy substrate.

Delosperma congestum : photo by Robert Pavlis

Delosperma congestum :photo by Robert Pavlis

I have had very little luck overwintering this plant in the garden, but it is easy to grow in pots and overwinter in a cold fruit cellar. In fall, reduce watering and allow it to dry out. A light frost will not harm the plant. Before the real cold weather sets in, take the pot into the basement and store it cold. Water it once a month or so. Even in complete darkness, Delosperma will remain green. In spring bring it outside and condition it for full light.

A cultivar, named ‘Gold Nugget’ or ‘Golden Nugget’, exists and I suspect most plants in gardens are this cultivar. There is also a ‘White Nugget’ with white flowers, but it is a cultivar of D. basuticum. I have seen a listing for D. congestum ‘Alba’.

Delosperma congestum : photo by Robert Pavlis

Delosperma congestum :photo by Robert Pavlis

Life Cycle: perennial

Height: 8cm (3in)

Bloom Time: summer

Natural Range: South Africa

Habitat: dry alpine regions

Synonyms:  none

 

Cultivation:

Light: full sun

Soil: well draining

Water: drought tolerant

USDA Hardiness Zone: (4?)(5?) 6- 9

Propagation: seed, division

Seedex availability (ORG&HPS annual Seed Exchange): rare

A

Sow @ 20°C. Seed germinates within 3 months.
Delosperma congestum MIDD 2014, 2017
Delosperma congestum WELS 2017, 2018
Delosperma congestum WELS 2017, 2018
Robert Pavlis