Primulas for Atlantic Canada

By Sterling Levy

There are more than four hundred species of Primula and new ones are still being found. In addition there are a lot of natural and man-made hybrids. From this large pool of plants only a few are being grown here. Many of them are too tender for Atlantic winters, some are not in cultivation, others are only grown in Botanical gardens or by specialists and are difficult or expensive to obtain. Even so, with a bit of effort there is still a wide variety of primula types that we can grow here in Atlantic Canada.

The least expensive way to get plants is to grow them from seed. The process is not too difficult but does require patience and some space in your garden (frames, nursery beds etc.) where you can pamper the small plants.

Seed Sources

There are a number of commercial sources of primula seed throughout Canada, USA and UK. Primula seed tends to be expensive. The seed exchanges of plant societies, especially Alpine and Rock Garden Clubs, are an excellent way of getting small quantities of seed. The American Primrose Society has a seed list that offers a wide range of different types at a reasonable price. The RSCAR seed list occasionally has a few primulas.

A word of caution, much of the seed is garden collected and is likely to be of mixed blood. A package of seed may produce plants that bear little resemblance to the official description of the plant listed on the label. They may still make good garden plants, often hybrids are more vigorous than the species.

Climate determines which primulas you can grow, especially the winter conditions. Our lack of snow cover, January thaws and cold wet springs all make growing some of these plants a challenge. Hot, humid summers can cause trouble as well. Where I garden, in Fall River, the winter temperature is often 5C colder than Metro Halifax and the coastal areas. I get my water from a well and cannot water extensively, so in summer areas of the garden become very dry and the plants suffer. Some winters I lose a lot of plants but they are worth the extra effort it takes to keep them going.

I am arbitrarily grouping the plants according to garden and habitat preferences and similar physical characteristics; I am also including hybrids as well as species. Any of the following are worth trying.

Polyanthus Types

This is a group of complex hybrids, some of which have been bred for the florist trade. They were developed from a number of European species and are characterized by their clusters of brightly coloured flowers. In some areas they are used for mass bedding with spring bulbs. Seed strains available are Pacific Giants, Cowichans, Gold Lace, and Wanda Hybrids. I find that many of the hybrids do not have a strong enough constitution for my conditions but are certainly worth trying in milder areas or areas with reliable snow cover. Seed from European sources seems to be the hardiest. The species in this group: Primula vulgaris, Wild primrose – Soft yellow
flowers; P. elatior, cowslip – nodding ,bright yellow; P. veris, oxlip – bright yellow; P. juliae – purple; P. amoena – white or violet, are all quite hardy.

Candelabra Group

These plants are native to various Asian mountain ranges. The flowers are arranged in rings or layers along a tall stem. They can get quite large, up to two feet in diameter. They need regular moisture when in full growth. They all go dormant in winter usually forming a fat bud at or slightly below the surface of the soil. When dormant they are vulnerable to rotting and should be kept as dry as possible. Good drainage is needed. They set large quantities of seed and will self sow in the garden if not dead-headed. Species to try are: P. aurantiaca, 12″ – orange yellow; P. beesiana, 2′ -rose-lilac; P. bulleyana, 18″ – red buds orange-yellow flowers; P. burmanica, 2′ – reddish purple; P. chungensis, 18″ – orange; P. cockburniana, 12″ – red-orange; P. pulverulenta, 3′ – crimson; P. japonica, 2′ – red to white (Miller’s crimson and Postford white are two seed strains available).

Sikkimensis Group

A small group of excellent garden plants. They are medium sized with clusters of flowers ( often scented) that are bell-shaped on a tall stem: P. alpicola, 18″ – white, violet, or yellow; P. sikkimensis, 2′ – yellow; P. florindae, 3′
– yellow; P. secundiflora, 18″ – red-purple; P. waltonii, 18″ – wine-purple.

Asian Woodland Group

Plants from China, Japan and Korea that are native to open woodlands. They all have “rounded”, hairy leaves with long petioles. They usually go dormant after setting seed in late summer and then disappear completely. It is a good idea to mark their place in the garden to prevent you from digging them up accidentally: P. polyneura, 12″- densely hairy leaves, mauve-pink blooms; P. saxitalis, 12″ – pink-mauve (P. cortusoides); P. sieboldii, 8″ – white,
pink, to purple including bi-colours, this latter is one of my favourites.

Farinose – “Bird’s Eye” Group

Most of these plants have two common
characteristics, a mealy coating (farina) on the leaves and stems, and a bright yellow “eye” in the centre of the flowers. They are small plants, typically four to eight inches tall, found all over the Northern Hemisphere growing in meadow or boggy conditions. The flowers are usually mauve-pink but occasionally white forms appear. They are good for rock gardens, small beds, troughs or pots. Most common
species are: P. farinosa, P. frondosa, P. modesta, P. scotica, P. laurentiana, P. mistissanica, P. darialica, P. rosea. Seed of any of these is worth trying although it may not be correctly labelled.

Auricula Group

Alpine plants from European mountain ranges, many are eagerly sought by rock garden enthusiasts. The flowers look like primulas but the foliage is thick, glossy and looks more like a succulent than the other primulas listed. Since they grow above the treeline some of them prefer a bit more sun and will tolerate drought. Many of them are spectacular in the garden with large clusters of brightly coloured blooms. Any seed you can get is worth trying. Look for P. auricula, P. carniolica, P. minima, P. x pubescens , P. rubra, P. marginata, P. clusiana, P. villosa, P. hirsuta, P. integrifolia, P. glaucescens, P. wulfeniana.

Garden and Alpine Auriculas are complex hybrids developed from P. auricula and other species in the group. They have large clusters of flowers, usually with a light centre and a darker colour band around the edge. Seed is offered in commercial catalogs as well as plant society seed banks. They are tough garden plants.

Miscellaneous

Here are a few others which are worth trying:
P. denticulata, 12″- Drumstick primrose, an early bloomer with ball shaped trusses of purple, pink, or white; P. vialii, 2′ – Unusual, has a spike of red buds which open to pale purple flowers;
P. chionantha, 16″ – A Chinese species with clusters of nodding white flowers, fragrant;
P. sinopurpurea, 18″ – Similar to P. chionantha but with violet flowers;
P. capitata, 12″ – A late (Aug.-Sept.) blooming species with pale purple flowers, somewhat tender and usually dies after blooming in my garden.

American Primrose Society
2630 W. Viewmont Way
Seattle, WA, USA 98199
Dues c. $20.00 per year ($US)

Some Primula Reference Books
Primula. John Richards (Timber Press, 1993)
Asiatic Primulas. Roy Green (AGS Publications, 1976)
Primulas of Europe and America. Smith & Burrow