The greater part of this genus are handsome climbing plants.
The only difficulty in its successful cultivation, in our climate, is the shortness of our seasons. It requires heat to bring it to perfection, and will not give general satisfaction, unless the plants are brought forward in the hot-bed.
If it is planted in the open ground, it will not be of any advantage to sow the seed before the last of May, as it will not grow till the ground is warm. Previous to sowing, the seed should have boiling water poured over it, which should remain until the water is nearly cold. If sown in a warm place, the plants will appear above ground in a few days. The plants are difficult to transplant, therefore the seeds should be sown where the plants are to remain. Without scalding, or unless the hull of the seed is taken off, it will remain in the ground a long time without vegetating. Plants thus raised will, in a warm season, do very well, but much inferior to those that have been forwarded in the frame. The seeds should be sown in a. hot-bed, with a brisk heat, in March, in small pots, a number of seeds in each pot, so as to be sure of two or three plants in each. In a month, if carefully attended, the roots will have filled the pots; it will then be necessary to shift the plants into larger ones. Before the first of June, the plants will begin to flower; but do not be in haste to put them into the ground; keep them in the frame, where they can be protected in case of cold storms, but expose them during the day to the full influence of the sun and air, by taking the sashes entirely off. By the 10th of June, the plants may be turned into the ground very carefully, so that the roots may not be disturbed. The ground should be made rich with well-rotted manure: the plants should be placed at the distance of one foot, or a foot and a half, if the object is to cover a wall or trellis. I have covered a trellis by the middle of August, twenty-five feet long and five high, with its elegant feathery foliage, so as to form a complete screen. The flowers, like those of the Morning Glory, appear in the morning and perish before noon. They are of a deep crimson color, and contrast finely with the rich green of the leaves. There is another variety, with white flowers. It should be sheltered from the northerly winds by a fence, trees, or buildings. An elegant cone may be made by setting a straight pole substantially into the ground, eight feet high from the surface; describe a circle round it, whose diameter shall be three feet; let about ten pots of plants be turned into the circle; drive down a stake by the side of each, nearly to the surface, to which tie a strong twine, that may be stained or painted green; let it be carried to the top of the pole and fastened there; then bring it down to the next stake, and so on until the whole is completed. With a little assistance the vines will climb the strings, and by the middle of August will be at the top of the pole, making a splendid show, more than paying i / all the trouble. It may be trained over an arch, or any other way fancy may direct. This beautiful vine is a native of the Southern States.
1. coccinea. - Scarlet Morning Glory. - A handsome species flowering in great profusion towards the close of the season, growing ten feet high; a native of the West Indies. The flowers are bright scarlet in one variety, and, in another, yellow and quite small; from July to the first hard frost. The seed may be sown from the 1st to the 10th of May, or treated like the Cypress Vine.
I. lacunosa. - Starry Ipomea. - This is also a handsome species; a North American plant; culture the same as cocci-nea; with delicate blue flowers, from July to September; ten feet high. There is also a variety with white flowers.
I. nil is a highly beautiful plant, with the corollas of a clear blue color, whence its name anil, or nil, (indigo); treatment same as the last, and flowering the same time, attaining the same height; a North American plant.