Some kinds (as poppies) do not bloom all summer, more especially not if allowed to produce seed. Of such kinds a second or third sowing at intervals will provide a succession. Preventing the formation of seeds prolongs their life and flowering period.
A few of the annuals thrive in partial shade or where they receive sunshine for half the day; but most of them prefer a sunny situation.
Any good garden soil is suitable for annuals. If not naturally fertile and friable, it should be made so by the application of well-rotted stable-manure or humus. The spading should be at least one foot deep. The upper six inches is then to be given a second turning to pulverize and mix it. After making the surface fine and smooth the soil should be pressed down with a board. The seed may now be sprinkled on the soil in lines or concentric circles, according to the method desired. After covering the seed, the soil should be again pressed down with a board. This promotes capillarity, by which the surface of the soil is better supplied with moisture from below. Always mark with a label the kind and position of all seed sown.
If the flowers are to be grown about the edges of the lawn, make sure that the grass roots do not run underneath them and rob them of food and moisture. It is well to run a sharp spade deep into the ground about the edges of the bed every two or three weeks for the purpose of cutting off any grass roots that may have run into the bed. If beds are made in the turf, see that they are 3 ft. or more wide, so that the grass roots will not undermine them. Against the shrub borders, this precaution may not be necessary. In fact, it is desirable that the flowers fill all the space between the overhanging branches and the sod.
It is surprising how few of the uncommon or little known annuals really have great merit for general purposes. There is nothing yet to take the place of the old-time groups, such as amaranths, zinnias, calendulas, daturas, balsams, annual pinks, candytufts, bachelor’s buttons, wallflowers, larkspurs, petunias, gaillardias, snapdragons, coxcombs, lobelias, coreopsis or calliopsis, California poppies, four-o’clocks, sweet sultans, phloxes, mignonettes, scabiosas, nasturtiums, marigolds, China asters, salpiglossis, nicotianas, pansies, portulacas, castor beans, poppies, sunflowers, verbenas, stocks, alyssums, and such good old running plants as scarlet runners, sweet peas, convolvuluses, ipomeas, tall nasturtiums, balloon vines, cobeas. Of the annual vines of recent introduction, the Japanese hop has at once taken a prominent place for the covering of fences and arbors, although it has no floral beauty to recommend it.
For bold mass-displays of color in the rear parts of the grounds or along the borders, some of the coarser species are desirable. Good plants for such use are: sunflower and castor bean for the back rows; zinnias for bright effects in the scarlets and lilacs; African marigolds for brilliant yellows; nicotianas for whites. Unfortunately, we have no robust-growing annuals with good blues. Some of the larkspurs and the browallias are perhaps the nearest approach to them.
For lower-growing and less gross mass-displays, the following are good: California poppies for oranges and yellows; sweet sultans for purples, whites, and pale yellows; petunias for purples, violets, and whites; larkspurs for blues and violets; bachelor’s buttons (or cornflowers) for blues; calliopsis and coreopsis and calendulas for yellows; gaillardias for red-yellows and orange-reds; China asters for many colors.
For still less robustness, good mass-displays can be made with the following: alyssums and candytufts for whites; phloxes for whites and various pinks and reds; lobelias and browallias for blues; pinks for whites and various shades of pink; stocks for whites and reds; wallflowers for brown-yellows; verbenas for many colors.
A garden of pleasant annual flowers is not complete that does not contain some of the “everlastings” or immortelles. These “paper flowers” are always interesting to children. They are not so desirable for the making of “dry bouquets” as for their value as a part of a garden. The colors are bright, the blooms hold long on the plant, and most of the kinds are very easy to grow. My favorite groups are the different kinds of xeranthemums and helichrysums. The globe amaranths, with clover-like heads (sometimes known as bachelor’s buttons), are good old favorites. Rhodanthes and acrocliniums are also good and reliable.
The ornamental grasses should not be overlooked. They add a note to the flower-garden and to bouquets that is distinct and can be secured by no other plants. They are easily grown. Some of the good annual grasses are Agrostis nebulosa, the brizas, Bromus brizæformis, the species of eragrostis and pennisetums, and Coix Lachryma as a curiosity. Such good lawn grasses as arundo, pampas-grass, eulalias, and erianthus are perennials and are therefore not included in this discussion.