This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Of the shrubby species belonging to this interesting genus, only two are hardy enough for open-air cultivation in this country. These are evergreens with a trailing habit of growth, indigenous to a somewhat wide area on the Continent, and probably also to Britain, where, if not really native, they are found in some districts in considerable abundance, growing, as one writer remarks, "in hedges and banks, in woods, but too often near pleasure •grounds." They were formerly known under the popular name pervinca or permit. and one or other of the species is alluded to by the old English poet Chaucer so early as the fourteenth century:—
"There sprang the Violet all new, And fresh pervinke rich of hew And flowers yellow, white, and rede, Such plenty grew there never in mede".
It is scarcely necessary to say that both species, with their varieties, are perfectly hardy, and that they grow freely in almost every variety of soil. Few of the low-growing evergreens are more valuable for covering bare ground under the shade or drip of trees; while, if not quite so luxuriant, they succeed very well on rough banks or rockeries with sunny exposures, which they soon clothe and render attractive with their abundant bright foliage and beautiful flowers. They are sometimes used for vases and hanging-baskets both in the open air and in the conservatory - a purpose for which, from their long, graceful stems, all the sorts are peculiarly adapted.
The long wiry stems of this species trail along the ground, and when in contact with soil strike root at almost every joint. The leaves are oblong lanceolate, and of a dark shiny-green tint. The flowers are light blue, usually produced in succession from March till September, though in mild seasons, when growing in sunny aspects, they are sometimes seen in midwinter.
This variety differs only from the species in having pure-white flowers.
Flowers double, bright blue; an exceedingly pretty and free-flowering variety.
The leaves of this plant are freely variegated with pure white.
Var. Aurea - with leaves variegated with bright gold. Both this and the preceding are very ornamental, and might be utilised with advantage in carpet-bedding and margins of flower borders.
This species is much larger in all its parts than the other. The stems being thicker, are sub-erect, rising sometimes 2 feet, after which the tops droop to the ground, giving the plant when standing alone the appearance of a dwarf, bushy-headed shrub. The leaves, which are fully twice the size of "minor," are ovate-cordate, minutely ciliated, and bright glossy green. The flowers vary in shades of blue and purple; they come out in succession from March till September, though they sometimes appear in midwinter.
A variety with fine golden variegated leaves. A superb plant, well worthy of a prominent place in any flower-garden or shrubbery border.
Another beautiful plant, with its leaves prominently netted with bright gold.
Leaves variegated with white.