New primroses or connoisseurs
- Primula 'Elizabeth Killelay' (a double-flowering, gold-laced polyanthus hybrid) ruffled, maroon blooms with yellow eye and gold edge; spring; full sun to part shade; 15 cm tall and wide; rock or woodland garden; Zone 3
- P. x polyantha 'Penumbra' (a silver lace polyanthus) deep purple petals with yellow eye and silver edge; spring; full sun to part shade; 20 cm tall and wide; rock or woodland garden; Zone 4
- P. x tommassini (you and me group) (hose-in-hose type) various colours; spring; full sun to part shade; 30 cm x 20 cm; woodland, rock or perennial garden; Zone 4
- P. veris 'Prinic' Katy McSparron (a double cowslip) golden yellow; late spring; full sun to part shade; 20 to 30 cm x 45 cm; woodland or perennial garden; Zone 4
A good basic growing mix for most primroses consists of one part soil, three parts organic matter (preferably leaf mould) and one part coarse grit or sand. As an alternative, clean, weed-free compost also works well. If you use peat for the organic matter, keep in mind that it lacks nutrients, so supplementary full-strength fertilizer must be added each month during the growing season. Of course, in the real world most of us have to make do with what soil is on site, amending it as best we can. Often improvement is gradual, sometimes taking a number of years. Here are the best soil mixes for specific types of primroses:
Woodland light, fluffy, well-drained but moisture-retentive organic soil with leaf mould and a small amount of clay
Rock garden one part soil, one part leaf mould (or peat) and two parts washed sharp builder's sand or fine grit
Bog and pondside half leaf mould and half well-composted cow or sheep manure; some growers use half peat and half soil
Container-grown well-rotted organic matter and clean grit in varying proportions, depending on species
Indoor-grown equal parts sterilized houseplant soil, peat and sharp builder's sand
Easiest primroses to grow
The most rewarding group of primroses for the average home gardener is likely the Juliana hybrids (Primula x pruhoniciana). These are low-growing, spring-flowering, easily pleased perennials of great beauty. With a bit of hunting, numerous cultivars can be found. Possibly the best known is 'Wanda', with purple-red flowers and purplish green leaves. Other cultivars to look for include 'Betty Green', 'Mrs. King', 'Dorothy', 'Lady Greer' and 'Kinlough Beauty'. Zones 3 to 4.
For sunnier gardens, it's hard to beat the auricula hybrids (though in very dry conditions they should be given some shade). These spring-flowering perennials have soft, smooth, pale green leaves, often liberally coated with a whitish or pale yellow waxy meal known as farina. They have a height and spread of 15 to 20 centimetres. Auriculas need particularly fast-draining soil, so are ideal for rock gardens or dry stone walls. They're easily raised from mixed seed, which is a good way to start a multi-hued collection. (However, note that named cultivars such as 'Linnet', 'Royal Velvet' and 'Old Irish Blue' must be increased by division, because seedlings of hybrids will be variable.) Zone 4.
Image: Primula pruhoniciana