Some alpines for your garden

Bernadette Vangool

A plant I’m anxious to add to my garden is Lewisia longipetala ‘Little Plum’. Lewisia longipetala is a rare species in the montiacea family. It was first discovered in 1806 by Meriwether Lewis, of the Lewis  and Clark expedition. Lewisia longipetala is endemic to the Sierra Nevada and found in only 20 locations, usually on north facing scree slopes near Lake Tahoe. This subalpine bloomer prefers rocky, well-drained, gravely soil. Another species, Lewisia cotyledon or Siskiyou Lewisia is native to Oregon and Northern California. ‘Little Plum’ is a chance  cross of two L. longipetala x L. cotyledon discovered in Scotland. It  was introduced in 2000 to the North American market by Jelitto Perennials.

‘Little Plum’ Lewisia forms small rosettes of narrow fleshy evergreen leaves, 15cm across The star-like, daisy flowers are born on stalks 15 cm high on plants of the same diameter Each flower typically has eight pink-purple petals between 1 or 2 cm long. ‘Little Plum’ blooms in late spring and develops a deep taproot. It is best left in place once established.

For those looking for a winter project next year, perhaps try to grow these little gems from seed, and plant them in a pot or in your garden in spring. Surface sow the seeds in a gritty,  fast draining media.  Cover them thinly with fine grit or sand and leave them at room temperature for 4 weeks. Then refrigerate them for 6 to 12 weeks. Next, bring them into a cool bright place around 15 degree C to germinate. Germination may take over 60 days. Although mature plants are drought-tolerant, seedlings require constantly moist (but not wet) soil. Once large enough to handle, plant the seedlings in pots or into the garden. These plants are ideal for rock gardens with gritty gravely soil. Plant them in full sun or partial shade.

Sticking with the rock garden theme, next up is Arabis caucasica or mountain rock cress, native to the Crimea, Turkey and Iran. In its native habita, it is found in limestone crevices and alpine meadows. It has become naturalized in Canada and the northern Unites States.
The species Arabis caucasica has a white flower, but for the plant sale we are bringing in ‘Pixie Cream’ which has more subdued creamy-white flowers. ‘Pixie Cream’ forms low mounds of grey green foliage, 15 cm high and 30 cm across. As this is a herb in the mustard family, the leaves are edible. The entire mound becomes  blanketed with 4-petaled, creamy white, sweetly scented flowers with a yellow centre, adding colour contrast to the garden in mid to late spring. ‘Pixie Cream’ should be planted in full sun in gritty, or sandy alkaline, well-drained soil. Allow the plants to dry out between waterings. This plant will tolerate poor soils and periods of drought, but tends to get leggy in hot weather with nude branches except for the terminal leaves. For healthier growth in summer and to encourage the spread of rhizomes, cut back the foliage after bloom. This, again, is a plant that does not like its roots disturbed. Pollinators are attracted, but deer not so much. Some years aphids can be a problem.

Last but not least, who has not been wowed by a great show of thyme in the garden. Thymus praecox ‘Coccineus’ forms a mat of evergreen, dark green leaves and is covered in rich mauve flowers in early summer. It thrives in full sun and is drought tolerant. It is great for rock gardens and is often used between pavers and as a ground cover to suppress weeds. An occasional shearing gives the plant a denser appearance. Red creeping thyme is native to the mountainous regions of Europe and Western Asia. Thyme has a long history in human culture. It was used for embalming in Egypt and in Rome it was associated with courage. Thymos is the Greek word for courage.

These three rock garden plants are on order for the Saskatchewan Perennial Society Plant Sale, to be held on Tuesday, May 26^th at 6:30 pm at the Saskatoon Forestry Farm Park Hall. Note that sometimes plants ordered are not delivered due to high demand or occasional poor growing conditions at the nursery.

This column is provided courtesy of the Saskatchewan Perennial Society (SPS; [email protected]). Check our website (www.saskperennial.ca) or Facebook page for a list of upcoming gardening events.

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