This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
Barrelier's Bell Flower (Campanula Barrelieri) is considered by a correspondent of the Garden one of the finest of all dwarf-growing Bell flowers for window culture; and, after trying many others, including C. pulla, C. turbinata, C.fragilis, and others, I have given this the preference. Grown in a pot of rich, sandy earth, it forms a bushy little plant in the spring, while a month or two later its branches elongate, until they hang gracefully over the pot sides, covered with pale, purplish-blue salver-shaped flowers. One of my plants looks splendidly just now, being a perfect mass of flowers. A good potful of this plant makes a capital substitute for a hanging basket; and the flowers show to better advantage when the plant is suspended in the window or on the balcony outside. It is also a capital bracket plant; or it looks well on the window sill, where the shoots can hang down freely. The two best campanulas for the window gardener are, undoubtedly, this and C. pyra-midalisy which are very distinct from each other in habit of growth, and both perfect in their way.