Whether a garden patch is devoted to vegetables or flowers, the scale of its border is important. To avoid overwhelming a small garden, the border should consist of relatively low-growing plants that will complement the vegetables or flowers they enclose and not compete with them. Annual and perennial plants are both suitable for borders; which to choose is a matter of personal preference and the amount of time available for gardening.
Growing only 6 to 9 inches in height, lobelia makes a fine annual border. It prefers cool summers, but will grow in warmer climates if shaded during the hottest part of the day. Lobelia is hardy in zones one through eleven and blooms prolifically all summer long. The most commonly seen variety has deep, royal blue flowers and dark leaves, but newer varieties of lobelia with brilliant red or white flowers have been developed. Lobelia is stunning when massed in a border and complements a host of other plants because of the contrast it provides.
In spite of their distinctive odour, which some find annoying, marigolds are beloved in plant circles. They are heavy bloomers, easy to grow in every planting zone, and though they are annuals, they reseed generously. Brilliantly coloured flowers in shades of yellow, orange, deep rust and red are accompanied by fine, lacy leaves. Flowers may be relatively flat and button-like, or crested and ruffled in appearance. Dwarf varieties may grow as tall as 12 inches, but many are in the 5 to 8 inch range making them ideal for borders. Marigolds are often planted with vegetables because they ward off insects. They bloom continuously through the summer until frost if spent blossoms are removed.
Alyssum, or sweet alyssum as it is sometimes called, is a hardy annual that will bloom year round in mild climates. It grows 8 to 12 inches tall and is covered with compact clusters of tiny flowers in white, pink, or lavender. Alyssum is a popular choice for an informal border because of its loose, spreading growth pattern, abundant flowers and sweet smell. Though somewhat fragile in appearance, alyssum is easy to grow and very tolerant of less than perfect soil and light conditions. When spent flowers are sheared back, alyssum blooms continuously.
For a permanent border that can take on a more formal aspect, liriope muscari is a proven winner. Slender leaves of dark green or green and white grow 12 to 18 inches long, but arch over and keep the profile low and rounded; spikes of handsome purple flowers appear in the spring. Liriope is a perfect choice for almost any garden type. It will look good enclosing vegetables or flowers and is an evergreen perennial that will grow well in zones seven through eleven. Liriope will grow in sun or shade and is not overly particular about soil type.