This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Perennial or more rarely annual or biennial herbs with blue or lilac or white flowers having a regularly lobed corolla and free anthers. This genus contains about 200 species. The name is from the Latin, and signifies a little bell, here applied in reference to the shape of the flowers. There are several native species, including one little gem seldom seen in cultivation, namely, C. hederacea, a small creeping species found in boggy places.
1. C. pyramidalis (fig. 152). - A very pretty though rather tender species with bright blue or white rather shallow corollas. It grows 3 or 4 feet high, with tufted ovate radical leaves and erect spikes of numerous flowers nearly 2 inches in diameter. A native of the mountains of South Europe, blooming towards the end of Summer.
Fig. 152. Campanula pyramidalis. (1/4 nat. size.)
2. C. Medium (fig. 153). Canterbury Bells. - A biennial species growing from 2 to 3 feet high, and remarkable for the large size of its flowers, which are constricted at the mouth. This is, or rather was, one of the commonest and most esteemed of garden plants. The typical form has blue flowers, but there are single and double white varieties, and, what is more remarkable, double and single rose-coloured varieties, in cultivation. Central Europe.
3. C. latifolia. - A perennial 3 to 4 feet high, and the handsomest of our indigenous species. Leaves ovate-lanceolate, acute. Flowers large, blue or white, solitary in the axils of the upper leaves, forming a terminal raceme. This species is commoner in Central Britain and Ireland than in the extreme north and south.
4. C. Trachelium. - Another native perennial species near the last, but differing in its hispid pe-tiolate coarsely-toothed Nettle-like leaves, the lower cordate at the base, and rather smaller flowers, two or more together in the axils of the leaves. The flowers are commonly blue, and there are both blue and white single and double varieties in gardens. This is common in the South of England, extending as. far northward as Forfarshire in Scotland. It comes into flower in September about the time the last is over.
5. C. glomerata (fig. 154). - This species has about the same distribution as the last, excepting that it is rare in the South of England. The clustered sessile flowers distinguish it from others in cultivation. Perennial, flowering in Autumn.
Fig. 153. Campanula Medium. (1/4 nat. size.)
Fig. 154. Campanula glomerata. (1/3 nat. size.)
6. C. nobilis. - A Chinese perennial species remarkable for the large size of its reddish violet or white or cream-coloured spotted flowers, which are 3 inches or more in length. It rises to a height of 18 inches or 2 feet. Leaves hairy; lower petiolate, ovate, toothed; upper lanceolate.
7. C. persicifolia. - A perennial species with linear serrulated coriaceous leaves and hemispherical blue or white flowers 2 to 2 1/2 inches in diameter. One of the commonest and handsomest of cultivated species, including some handsome double-flowered varieties. It grows from 2 to 3 feet high, and continues blooming from June till September. A native of the South of Europe.
8. C. rotundifolia. Hare-bell. - A common indigenous species, owing its specific name to the fact of its lower leaves being rotundate or ovate in outline. The stem-leaves are linear and entire. Stem slender, from 1 to 2 feet high, bearing a few-flowered raceme of drooping flowers on slender pedicels. The graceful habit of this plant renders it equally attractive with the larger flowered species. There are white and pink varieties, but the ordinary blue one is perhaps the handsomest.
9. C. grandiflora (fig. 155), syn. Platycodon grandifiorus. - A perennial species about a foot high, of straggling habit. Flowers deep dark blue, appearing in July. Native of China.
10. C. Carpathica (fig. 156). - A tufted perennial usually about 9 inches high. Leaves cordate, toothed. Flowers hemispherical, on long slender pedicels. There are several varieties of this desirable species in cultivation, with blue, blue and white, or entirely white flowers. This is perhaps the best of the dwarf species.
11. C. Garganica. - An elegant little species with slender stems barely exceeding 6 inches in height. Flowers drooping, pale blue and white, funnel-shaped, with deep narrow lobes; pedicels very slender. Leaves ovate or cordate, toothed. A native of Southern Italy, flowering from June till August.
Fig. 155. Campanula grandiflora. (1/4 nat. size.)
Fig. 156. Campanula Carpathica. (1/4 nat. size.)
C. speciosa is a handsome hairy species near C. glomerata with the corollas of a darker tint within; C. pumila is a very diminutive species with deeply campanulate white or blue flowers; C. rapunculoides is an indigenous plant 1 to 2 feet high with large blue flowers having the corolla lobes recurved.
Phyteuma is an allied genus having a rotate corolla with narrow linear lobes, free anthers, and the flowers usually in dense heads or spikes. Ph. orbiculare, a native species, found only on the chalk downs of the South; flowers deep bright blue, in dense terminal heads. Ph. spicatum, a very local Sussex species, with creamy white flowers in elongated spikes.
Ph. campanuloides has racemose blue flowers. Jasione differs from the foregoing in having connate anthers. J. perennis and J. montana, Sheep's-bit, are dwarf blue-flowered plants of no great beauty, the latter being indigenous.
Symphidndra pendula is separated from Campanula on account of the broad hairy filaments and connate anthers. It is an herbaceous plant about 18 inches high with large drooping creamy white flowers. Caucasus.