This section is from the book "The Gardener V1", 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.
This is a very numerous and natural group of plants. A strong family likeness pervades the whole, yet there is much diversity of habit and stature, which renders them useful for many purposes, and fit for a variety of positions. From the bright and beautiful character of the few species with which we are familiar in cultivation or in nature in this country, we may fairly estimate the ornamental value of a large number of the perennial species. Our own "Scottish Blue Bells," which, with grace and brightness, light up for a long period in summer the hedge-banks and waste places all over the country, may be taken as a fair type of the family in both the scientific and practical sense. A few species from Madeira, the Cape of Good Hope, and Australia, are suitable only for frame or greenhouse culture; but the great home of the family being northern and southern Europe and western Asia, a very large majority are hardy enough to endure the severest winters of our climate. They are all of easy culture.
Campanula Garganica is about 6 or 9 inches high, somewhat tufted and prostrate, throwing out numerous branches, which, from May till July, are rather profusely covered with the light-blue flowers. The flowers are broadly campanulate, and deeply cut into five spreading lobes. This is a very desirable species, and is most suitable for planting on rockwork; but in light, rich, well-drained soil it is available also for the front lines of mixed borders. In some catalogues it is entered as a biennial; the plant is, however, perennial and hardy, but impatient of wet undrained soil.
Campanula Elatine is nearly related to Campanula Garganica. It is prostrate and tufted in growth, and hairy in nearly every part. The flowers appear in June and July, are pale blue, broadly bell-shaped, and deeply cut into five narrow spreading lobes. A distinct and desirable sort, best fitted for planting on rockwork. Native of Piedmont.
Campanula Electinoides closely resembles the last-named sort, but is downy and hoary all over, even to the lobes of the corolla. It flowers in July and August; the flowers are blue, deeply cut into five lanceolate spreading lobes, and borne in rather close racemes. Suitable for rockwork, and planting on dry stony banks. Native of Lombardy.
Campanula Frecgilis, Syn. Campanula Diffusa, is a dwarf tufted species, sending out numerous prostrate branches. The flowers, borne in loose racemes, are bright blue, broadly campanulate, but not so deeply divided as those of the foregoing species. It is a bright free-flowering plant, which about July and August forms beautiful masses of blue. Native of the mountains of Naples and Sicily, and hardy as the rock it clings to, if protected against stagnation of moisture. Erroneously included among the half-hardy species in some lists. A variety named Hirsuta is peculiar in aspect, but not so free flowering as this species.
Campanula Isophylla, Syn. G. Floribunda, has much of the appearance of Campanula fragilis, but has broader leaves, is more dense and tufted in growth, and a more profuse bloomer. The flowers, which appear in June and July, are pale blue with a grey centre. Native of Liguria; perfectly hardy, but impatient of wet.
Campanula Rotundifolia - "Scotch Blue Bells" - though not very "far fetched," so wonderfully increases in beauty under care and culture, that I cannot pass it over in this list, but strongly recommend it to all who may not have given it a trial. It is one of the most graceful, profuse, and lasting of Campanulas, and adapts itself readily to any position. A white and also a pink variety occasionally to be met with are interesting and pretty.
Campanula Pusilla is a diminutive species in the way of Campanula rotundifolia. The flowers are pale blue, appearing in June and July in small loose nodding racemes. It is from the Swiss Alps, and chiefly valuable because of its great pertinacity of life in dry stony positions.
Campanula Cenisia is a very diminutive species, rising to the height of only 3 or 4 inches, forming a close carpet of lilac-blue flowers, large in proportion to the plant. One of the prettiest and most interesting in the family, found at a great elevation on the Alps of Italy. Most suitable for rockwork. Flowers in July and August.
Campanula Pumila in the form of the white variety, one of the best known of the smaller Campanulas. Like the last-named sort, it forms a close carpet of flowers, which appear in June and last till August. The blue form is not so common, but both should be in every collection of hardy herbaceous plants, as it is one of the most graceful and profuse-flowering, and a most accommodating plant, thriving alike well in nearly every variety of soil and position. Native of hilly pastures in Switzerland.
Campanula Zoijsii is a tufted species, with erect flower-stems from 6 to 9 inches high, bearing long campanulate dark-blue flowers about July and August. Found on mountains and rocks in the Tyrol, and is best suited for planting on rockwork, but succeeds well also in light rich soil in well-drained borders.
The blue forms of Campanula pusilla and Campanula pumila are sometimes sent out for this species. It is rather rare in the country, but is a very desirable and distinct plant. It is dwarf, rarely exceeding 8 inches high, with erect simple flower-stems, bearing each a solitary bright blue flower, somewhat recurved on its stalk. The leaves are bluntly oval on short stalks. Flowers in June and July. Native of south-eastern Germany, on mountain-pastures. Suitable for rockwork, or for the open border in light, rich, well-drained soil.
Campanula Alpini an erect species, about 1 foot high, each stem bearing a pyramidal panicle of showy blue flowers, which appear in June and July. Native of Italy and the east of Germany.
Campanula Latifolia is a fine stately sort, of erect habit, with simple stems, which, in rich soil, reach the height of 5 feet, and are terminated by a long leafy raceme of purple flowers, appearing in July and August. This species is invaluable for planting in woods. It reaches its greatest magnitude and beauty in rich loam, but makes a fine display in poor, shallow, and even dry soil, if partially shaded by trees overhead. There is a dull white-flowered variety, which forms a good contrast to the purple one. Native of woods in the north of England and south of Scotland, and is widely spread over northern Europe and western Asia.
Campanula Rapunculoides grows to the height of about 3 1/2- feet in cultivation, with simple erect stems, terminating in graceful leafy racemes of dark-blue flowers in June and July. One of the most showy of the family, the inflorescence being of great length - often 1 1/2 foot. It is very suitable for planting in woods and other semi-wild places. It is striking also in the mixed border, but rather troublesome, and encroaching by means of its creeping underground stems. Native of woods in Britain, Europe generally, and western Asia.
Campanula Trachelium is a tall handsome species, with erect stems 3 or 4 feet high, and large violet flowers, arranged in terminal leafy racemes, which appear in July and August. In the early stages of growth it resembles the common Nettle, having large coarsely-toothed leaves of the same form. Its geographical distribution is nearly the same as that of Campanula latifolia, and it is found inhabiting similar places, and may be used for the same purposes. There are three varieties, showy and desirable - the double blue, double white, and single white.
Campanula Persitifolia one of the handsomest, and at the same time one of the most common, species. It reaches the height of 2 or 3 feet, the large broadly-campanulate blue flowers being arranged in a close raceme along the greater part of the stems. It begins flowering in June, and lasts on till September. There are five or six varieties, all very beautiful: grandis, flore pleno, alba, and alba flore pleno. The species, along with its varieties, should be more extensively cultivated than they are. There are very few more showy hardy herbaceous plants.
Campanula Garpatica is of dwarf growth, throwing up its bright blue, broadly-campanulate, erect flowers to the height of about 9 inches or 1 foot on simple stalks. There is a very fine companion to the blue form, in the white variety, named Campanula Carpatica alba, which in every respect is like the species, only the flowers are pure white. Flowers from June till August. A very handsome and showy species, which should be in every garden. It adapts itself to almost any position, and will do well in almost any soil if moderately rich. Native of the Carpathian Mountains.
A very beautiful species recently introduced by Messrs Backhouse. The flowers equal in size those of Campanula Carpatica, but are dark purple. The plant is more dwarf, but of the same tufted habit of growth. Native of Transylvania.
Campanula Glomerata grows about 2 feet high, with many flexuose, almost straggling, stems, bearing terminal and auxiliary heads or dense clusters of flowers. The flowers are small individually, but collectively they form a large and effective inflorescence. The most common colour is deep purple or violet, and of this there is a double variety. But there is also a pure white sort, single and double, that is very ornamental and desirable. The flowers last from June till September. Native of the south-eastern counties of Scotland and the greater part of England, and extends over most of Europe and Russian Asia. Fond of rather a dry sunny position and rich soil.
Campanula Speciosa from Siberia, is nearly related to Campanula glomerata, and is mainly distinguished from it by its larger individual flowers and flower heads.
Campanula Cervicaroides from Italy, with long straggling stems, so closely resembles Campanula glomerata that it is scarcely worth having where the other can be got.
Campanula Aggregata from Bavaria, is the finest of the cluster-flowered Campanulas. It is about 2 feet high, with crowded clusters of pale-blue flowers, which last from June till September. Like Campanula glomerata, it delights in a warm sunny position and rich light loam.
Campanula Alpina a handsome dwarf species from the Tyrol, resembling Campanula rotundifolia, but is more dwarf and compact, and with larger dark-blue flowers. Best suited for planting on rockwork. The flowers appear in July. W. S.