There are many situations, especially in the making of new landscapes, where nothing can fill the bill quite like annuals. If you’ve moved into a new house and just finished the initial landscaping, the garden is liable to look a little bare for the first year or two. In this case, annuals are indispensable. For a nominal investment, you can fill in among immature shrubs and trees with color spots of annuals and create a big improvement in only a little time.
Some ground covers, for example, are notoriously slow to knit into a solid carpet. For the first few years after planting, you could fill in the bare spots with low, fast-growing annuals, such as sweet alyssum, California poppy, or candytuft. Depending on the annual, these may reseed themselves and continue to come up year after year until the ground cover fills in. Another advantage of this method is that any time you should decide to thin them or eliminate them completely, it’s easy to pull or hoe them out before they can set more seed.
If you are renting a house, or know you are not going to be in one location for very long, annuals can provide the look of a glorious garden at far less expense than permanent landscaping. In one short season it’s possible to completely change your outdoor surroundings.
Some of the most often overlooked plants for quick color are the annual flowering vines. For the most part, they grow at an almost unbelievable rate: The old-fashioned morning glory, scarlet runner bean, and sweet-scented moonflower (Ipomoea alba) can, under the right conditions, grow from 8 to 25 feet in a single season.
As temporary screens against fences, or shade-providers covering arbors or trellises, flowering vines are unequaled. In hot climates, some gardeners even save home cooling costs by using them to screen south and west windows. They can be planted alone or in combination with other, slower-growing but more permanent vines, and in addition to privacy and shade, offer attractive flowers.