A narrow 12 inch wide flowerbed need not be abandoned to weeds or smothered in landscape bark. While a container is limited in its depth, a narrow flower bed can have a growing medium worked and supplemented with rich, organic amendments to 2 feet deep. With soil quality built to a premium, a vast array of annuals, perennials and ground covers will thrive in the narrow space.
A narrow flower bed provides room for a combination of tall and short annuals. Pack them in closer than the seed packet or tag advises, since they are only a one-season plant. This is the same technique used in flower baskets. A complementary combination is tall, yellow-and-orange sunflowers with short, white, sweet-scented alyssum covering the entire base. Another is 4 foot high sensation cosmos, as a back layer with godetia in the front covering the lower stems of the cosmos. The colours of both blend, as they are a mixture of pink, rose and white.
For the narrow flower bed that requires little care and a low profile, plant flowering ground cover. For early spring blue flowers, plant veronica liwanensis. It hugs the soil with glossy evergreen leaves creating a thick blanket covered with an abundance of spikes of flowers. Blooming for months beginning in spring is the white-flowered soapwort (Saponaria ocumoides). It will easily fill in the entire narrow bed, appearing as a single mass of white bloom. Thymus pink chintz provides a summer blooming option with evergreen foliage topped with pure pink flowers.
If a single white flower covering the entire bed is desired, plant the common form of candytuft (Iberis), Little Gem. It provides evergreen foliage nearly hidden in spring by the large flower clusters. For a combination of short and tall perennials, tuck Delphinium elatum in the back for a mix of blue, purple and white with the shorter delicate blues of forget-me-not (Cynoglossum amabile) in the front.
A narrow bed has room for a riot of spring colour with bulbs. Daffodils, tulips, hyacinth, allium, scilla, crocus and muscari provide colours from which to choose. Hide the fading foliage by sowing seed of an easy, fast-growing annual between the bulb plants, such as nasturtium or marigold.
Although most lavender (Lavandula) grows to sizes of 3 to 4 feet, variety lavender lady is a dwarf that will fit nicely in the narrow flower bed. Prized for providing scent to the entire yard, this variety grows quickly and blooms the first year with deep purple flowers.