The heliotrope has long been the queen of all flowers grown for fragrance. It is grown readily from either seeds or cuttings; the latter generally rooted in the spring. For blooming in winter, start young plants in February, or cut back old ones after flowering, and keep growing but pinched back and disbudded, in partial shade during the summer.
There are several varieties, from dark purple to very light and white. Lemoine's hybrids have the largest flowers, but are not so fragrant as some of the smaller sorts.
By pinching off the side shoots and training to a single main stalk, the plants may be grown as formal standards, with the flowering branches several feet from the pot, like the head of a tree. For certain uses they are appropriate, but I think not nearly as beautiful as when well trimmed to shape and grown in the ordinary way.
The heliotrope objects to any sudden change, whether of temperature, watering or soil, and will readily turn brown and drop all its leaves. Giving it proper care and cutting back, however, will quickly bring it into good humor again.
Petunia
The petunia is one of the most easily grown and generous bloomers of all house plants. It is, however, a little coarse and some people object to its heavy odor. The flowers are both single and double, each having its advocates. Both have been vastly improved within the last few years. Certain it is that some of the new ruffled giant singles are remarkably beautiful, even as individual flowers; and the new fringed doubles, which come in agreeable shades of pink, variegated to pure white (instead of that harsh magenta which characterized the older style) produce beautiful mass effects with their quantities of bloom.
They are grown either from seed or cuttings, the latter frequently blooming in the cutting box, if allowed to. In raising seedlings, be sure to save all the slowest growing and delicate looking plants, as they are fairly sure to give some of the best flowers, the worthless singles growing strong and rank from the start. Plants growing outdoors during the summer may be cut back, potted up and started into new growth. The singles bloom more freely than the doubles, especially indoors. After blooming, cut the plants back to within a few inches of the root, repot or give liquid manure and a new growth will be sent up, and soon be in blossom again.
Primroses
Of the deservedly popular primrose there are two types, the Chinese primrose (Primula Sinensis) and Primula obconica. Both are favorites, because of their simple beauty and the remarkable freedom and constancy with which they bloom. Another advantage is that they do not require direct sunlight. Primroses need no particular care. The soil may have a little extra leaf-mould and should slope toward the edges of the pot, to prevent the possibility of any water collecting at the crown of the plant, which must be left well above the soil when potting.
The easiest way to get plants is to buy small ones from the florist every spring. They may be raised from seed successfully, however, if one will take care to give them a shaded, cool location during the hot summer months, such as a coldframe covered with protecting cloth, or any light material that will freely admit air. From seed sown in February or March they should be ready to bloom by the following Christmas. It does not pay to keep the plants over for a second season.