Carnations are among the most popular border perennials. Carnations have large, fragrant blooms of red, yellow, pink or white. They bloom during the summer and fall months and look beautiful outdoors in the garden, or inside in a vase. The dainty lilac has pink flowers and blooms heavily during the spring, reblooming either in late summer or fall. Lilacs attract butterflies and hummingbirds.
Citronelle plants provide good ground coverage with their mass of lime-green foliage. Some varieties of citronelle are resistant to plant-eating deer and small animals. Foxglove grows to heights of up to 36 inches and has pastel-colored trumpet flowers with colorful speckles. Foxglove is poisonous when eaten, so some caution is recommended. Goldstrum is a hardy border perennial that has bright yellow flowers with brown centers. This plant produces an ample amount of blooms during the summer and fall. Golstrum grows up to 36 inches in height, with an average spread of 18 to 24 inches.
There is no blueprint to follow for planting border perennials. Gardeners may opt to plant mixed borders instead of devoting whole sections to one type of plant. Fortunately, perennials are easy to move around. Usually, tall border perennials are placed behind shorter varieties. However, tall varieties also look nice as a midsection showpiece.