PRIMROSES are one of the joys of Easter. Primula vulgaris grows almost anywhere in Scotland – in hedgerows, at the edges of woodland, on coastal cliffs and slopes. The bank below my orchard is carpeted with a mass of these cheery lemon stars.
The beautiful native primroses, including their cultivated varieties, have become essential for most gardens, as have polyanthus, with several flowers on a single stem. These plants hybridise so freely that breeders have developed an endless range of colours and doubles.
Although some gardeners treat primroses as annuals, they are known to live for a long time. The botanist George Peterken noted this at the end of a two-decade-long study. In 1993, he identified 37 individual clumps of P vulgaris growing in a nearby wood and 21 years later found 16 were still alive.
Primulas form clumps, with the central plant producing clones: as the original plant weakens, its peripheral clones grow outwards and, in turn, propagate clones that are identical to the original. Many primulas, from P denticulata, the drumstick primula, to P florindae, the tallest species, spread and clump this way.
The clone-forming process raises the question: what is an individual plant? We normally perceive plants behaving like us – growing from seed, living, setting seed then dying. But, if a plant generates genetically- identical clones, does it ever die, as is suggested by many scientists?
We all know about ancient oaks living for centuries, but clone-forming plants can be just as venerable. Scientists have identified a lily of the valley, Convallaria majalis, growing in southern Finland and they estimate it has a diameter of 850m and that it is at least 670 years old.
When propagating primroses, the usual method is to divide an often congested clump into several plants. The clones are both part of the greater plant and separate plants, with their own root system, crown and tuft of leaves.
You can divide primroses immediately after flowering or in the autumn. Most primulas need moist or even boggy ground, so gardeners south of the border divide them in the autumn rather than before a hot summer. We seldom have that problem so I prefer to divide in May.
After lifting a clump, you can easily identify the individual plants within. Shake off loose soil and tease the roots, replanting the larger crowns. Trim roots to around 10cm and remove large leaves. Soak the roots for several hours and plant them in damp, fertile soil. Discard the old woody plants from the middle.
As a rule, primulas are tough. I have even lifted and moved a clump bursting into flower because it was the wrong colour for a bed. And, against the odds, primulas sometimes survive in dry, gritty soil, as they did for the great plantswoman Gertrude Jekyll when she grew a special polyanthus in her garden at Munstead Wood in Surrey.
Jekyll lifted and divided the plants every year, instead of the usual two or three. When in Home and Garden (1899) she describes her role in the proceedings, she tells us she sat on a low stool for two days, where a boy “feeds me with armfuls of newly-dug up plants, two men are digging-in the cow-dung at the far end, and another carries away the plants, tray by tray and carefully replants them”.
Primulas naturally spread vegetatively and are poor seed dispersers because their large seeds drop close to the parent plants. Ants, rodents and possibly slugs do admittedly spread them a little wider. But it’s tricky getting mature seed to germinate, so dividing is the best approach.
Primulas are hardy but tend to be poor seed dispersers, spreading vegetatively instead