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.
The Rocket Larkspur was introduced into England, from Switzerland, in 1573, although not supposed to be a native of that country. It is of a compact habit of growth, and its blossoms appear set around the raceme, forming a dense mass of blossom; and its beauty has made it a great favorite for more than two hundred and fifty years.
It requires a rich soil to bring it to perfection, and an addition of leaf mold from the woods will tell a good story when the plants are in bloom. There are few plants that will better reward good culture. The seed should be sown in drills, where the plants are intended to blossom, as they will not bear transplanting. When the young plants come up, they will require but little thinning, and may be left standing within two inches of each other; as from their compact habit they require but little room, and should be seen in masses to produce a fine effect. These plants are of such a neat and symmetrical growth, that any device, such as a name, can be well made with them. The time for sowing is in April.