There are some plants about which it is hard to get excited — the ones that appear in gardens again and again but do not always get noticed. Vinca is one of these but it actually fills a very valuable role in gardens, that of sturdy, vigorous ground cover, and it will cope in almost any conditions.
Vinca is classified as Apocynaceae, the family with milky sap, and they are known commonly as the periwinkles. It is a genus of seven species of evergreen subshrubs or herbaceous perennials, natives of Europe, North Africa and West and Central Asia.
They all have prostrate or arching shoots and the stems root again as they touch the ground, meaning they make excellent ground cover. Their flowers appear in the leaf axils and are salverform, with five petals creating a neat whirl, like the sails of a windmill. These are usually blue or violet, occasionally white or plum purple. The leaves are generally neat and ovate, arranged oppositely along the thin stems.
The evergreen trailing shrubs are the ones seen in UK gardens. The two best known, and which have a large number of varieties, are the greater periwinkle, V. major, and the lesser periwinkle, V. minor. The leaves of V. major are larger and dark glossy green. This species is highly vigorous and begins with ascending shoots that later lengthen and root at the tip. The smaller-leaved V. minor has stems that root at intervals. Both species have attractive bright-blue flowers from April to June and often intermittently until autumn.
There are numerous good varieties, including some with interesting leaf variegation and flowers of an unusual shade. V. major ‘Variegata’ Award of Garden Merit (AGM) has creamy margins. V. minor f. alba ‘Gertrude Jekyll’ has pretty white flowers. Another unusual-coloured variety is V. minor ‘Atropurpurea’ AGM, which has gorgeous deep plum-purple flowers. A choice variety is V. minor ‘Bowles’s Variety’ AGM (syn. V. minor ‘La Grave’) — its flowers are larger than the type and they are a striking azure blue. V. minor ‘Azurea Flore Pleno’ AGM also stands out for having a sky-blue double flower.
The only other species generally cultivated in the UK is V. difformis, also known as the intermediate periwinkle. This species flowers much earlier, at some point in late winter or early spring. It has very pale lilac-blue flowers formed like a delicate propeller and is usually herbaceous in cold areas.
Vinca can be planted in almost any kind of soil, in sun or shade. They spread rapidly and therefore can be used to create ground cover in any location, which makes them very useful for planting in difficult situations like a slope or in shady places under trees. Shoots of V. major may be cut back in late winter before growth begins again, to keep them neat and renew older shoots, but otherwise they can be left to scramble where they will.
Chris Day from Buckingham Nurseries & Garden Centre recommends planting bold groupings of Vinca in odd numbers to create a mat-forming tapestry effect over a large area. He also suggests that periwinkles can be used in larger rockeries where evergreen interest is needed.
V. minor ‘Atropurpurea’
What the specialists say
Morris Hankinson, managing director, Hopes Grove Nurseries, Kent
"Vinca are a very useful group of plants. We sell them mostly for ground cover. They will establish even in the more difficult settings of shade and on banks. Low maintenance is a key selling point, as is their tolerance of aspects from full sun to full shade. Vinca is also very drought-tolerant once well established, so overall we think they are a great landscape plant.
"We sell the older established varieties of V. major and V. minor, all as two-litre pots. V. major ‘Variegata’ and the V. minor varieties ‘Gertrude Jekyll’ and ‘Bowles’s Variety’ are the most popular.
"They are easy plants that need little attention. Keeping them trimmed and spaced keeps problems at a minimum and the plants looking nice for most of the year."
Chris Day, garden centre publicity manager, Buckingham Nurseries & Garden Centre, Buckingham
"We find all the smaller-leaved Vinca sell well and we tend to promote them as a versatile evergreen ground cover plant. They are good doers, especially if the soil is reasonably prepared with some organic matter and the area is kept relatively weed-free. They are very easy to grow and certainly don’t succumb
to any major pests or diseases.
"On the nursery, keeping them sufficiently spaced apart is important because they can easily root into neighbouring pots if you are not careful. In small 9cm pots, we tend to regularly liquid feed from early March until September, using a high-potash feed plus some seaweed extract.
"We tend to favour V. minor ‘Illumination’ as one of our favourites. This evergreen carpeter has stunning bright golden leaves with narrow dark-green margins on pink-tinted stems. It holds its colour well even in the shade, so is excellent for brightening up a shady area. Pale lavender-blue flowers come in April and June, and sometimes again in the autumn.
"This would be closely followed by V. minor f. alba ‘Gertrude Jekyll’. This form has a very compact neat habit, green foliage and a profusion of small starry white flowers. Popular with our customers is V. minor ‘Bowles’s Blue’, with its highly attractive deep-green foliage and outstanding large lavender-blue flowers. Its punchy presence in spring and early summer certainly attracts the eye."
V. minor f. alba ‘Gertrude Jekyll’
Species and varieties
V. difformis, also known as the intermediate periwinkle, produces upright stems bearing pretty pale-blue to nearly white flowers from late winter to early spring. It has fresh-looking, ovate, evergreen leaves on stems that spread and root. Can be damaged by frost so plant in a sheltered area. Height: 30cm.
V. difformis ‘Jenny Pym’ is a pretty variety with deep-lilac flowers that have white centres and petals narrowly margined with white, from late winter to early spring. Glossy dark-green leaves. Height: 30cm.
V. difformis ‘Ruby Baker’ is a vigorous form with trailing stems bearing olive-green leaves and
rich pinkish-purple flowers. Height: 45cm.
V. difformis subsp. sardoa is a Sardinian species with attractive, large, pale, smoky violet flowers in late winter and early spring, above glossy dark-green foliage with paler venation. Height: 35cm.
V. major, which is also known as the greater periwinkle, is a vigorous evergreen subshrub. It produces erect stems bearing glossy ovate leaves and starry violet-blue flowers. The long rooting sterile stems make effective ground cover. Height: 45cm.
V. major ‘Variegata’ AGM (H6) is a vigorous variegated evergreen subshrub that has erect leafy flowering stems and long prostrate rooting stems. Its ovate leaves are dark-green with creamy white margins and it produces large blue-violet or dark-violet flowers with white centres, on arching shoots, from April through to September. Height: 45cm.
V. minor ‘Argenteovariegata’ AGM (H6) is a lesser periwinkle with greyish-green ovate leaves, margined with creamy white, and light violet-blue flowers. Height: 10cm.
V. minor ‘Atropurpurea’ AGM (H6) is a lovely variety with shiny green leaves and purple flowers
from April to June. Height: 10cm.
V. minor ‘Aureovariegata’ has yellow blotched leaves and sky-blue flowers. Height: 10-20cm.
V. minor ‘Argenteovariegata’
V. minor ‘Azurea Flore Pleno’ AGM (H6) has small shiny green leaves and lovely double sky-blue flowers from April through to June. Height: 15cm.
V. minor ‘Bowles’s Variety’ AGM (H6) (syn. V. minor ‘La Grave’) is a vigorous and attractive variety with dark-green ovate leaves and lovely neat lavender-blue flowers over a long period from April to September. This is regarded as the best blue-flowered variety and less invasive than V. major. Height: 20cm.
V. minor f. alba ‘Gertrude Jekyll’ is a lovely pure-white form of the lesser periwinkle. It forms a compact mat of small, dark-green ovate leaves. Height: 10cm.
V. minor ‘Illumination’ has bright-yellow leaves, narrowly margined with dark-green. Delightful pinkish-red stems bear deep violet-blue flowers that can appear in May and sporadically throughout the rest of the growing season. Height: 10cm.
V. minor ‘Ralph Shugert’ AGM (H6) is a popular form of lesser periwinkle that has dark-green leaves with narrow yellowy-cream margins. Its large attractive flowers are deep-violet. Height: 20cm.
Thank you to Floramedia, which supplied the images for this article from its photo library www.floramedia-picture-library.com