Border gardens sit in front of a background, like a fence, building, wall or shrubbery. Although there are many kinds of plants used in border gardens, some plant characteristics are more important than others. Height is one of the most important factors. In addition to height, the garden location, blooming period and color of the plants are other factors. Plants should be kept in odd-numbered groups and consider foliage color and longevity when planning the border garden.
Tall Garden Phlox
Tall garden phlox (Phlox paniculata) is hardy in U.S. Department of Agriculture Hardiness Zones 4 to 8. This perennial plant grows 2 to 3 feet high and has pink, blue or white flowers that sit in clumps on top of the foliage. Tall garden phlox lives in full sun or part shade, prefers good circulation and moist, well-drained soil. Lack of circulation causes mildew to form, and fungicides may be needed. Tall garden phlox does not like extreme heat. This plant makes a good background plant in the border garden.
The hollyhock (Alcea rosea) produces a spike of bell-shaped flowers. These perennials grow between 5 and 9 feet tall and make good background plants in the border garden. Hollyhocks like full sun and moist, well-drained soil. To prevent rust from spreading, infected hollyhocks should be cut back to the ground when flowering is done. Hollyhocks grow in USDA Hardiness Zones 3 to 8.
Butterfly weed (Asclepias tuberosa) grows 12 to 24 inches tall and blooms between June and September. The bright orange flowers sit in a cluster on top of the dark green foliage. This flower attracts butterflies. Butterfly weed prefers very well-drained soil and full sun and is hardy in USDA Hardiness Zones 4 to 9. This plant can be used near the rear of the border garden.
Bleeding heart (Dicentra spectabilis) is hardy in USDA Hardiness Zones 2 to 9 and grows up to 30 inches tall. This perennial produces pink and white flowers that hang like bells. Bleeding heart prefers sun or light shade and ample water in the spring and summer. This plant must be protected from high winds. This plant flowers in the early summer and then dies down. Bleeding heart works well in the middle of the border garden and near other plants that will bloom later in the season and cover the gaps left by this plant.
Coral bells (Heuchera sanguinea) grow in USDA Hardiness Zones 3 to 8 and produces red, pink, purple and white flowers. The flowers grow on spikes and are bell shaped. This perennial grows up to 2 feet high. Coral bells prefer not to grow in clay. Remove the old flowers to get the plant to rebloom in the fall.
The tunic flower (Tunica saxifraga) grows in USDA Hardiness Zones 5 to 7. This 8 inch tall perennial produces pink and white flowers. Tunic flowers prefer full sun and well-drained soil. Single- and double-flowered varieties are available. Tunic flower is a good plant for the edge of the border garden.