Unlike annuals that add instant color to the landscape, perennials have short blooming seasons. Some gardeners find it a challenge to keep the perennial garden in bloom throughout the growing season, but knowing the mature height and flowering season of each plant is a key to continual color. Perennials planted according to height and bloom times will give the visual effect of drifts of colors and textures that can be enjoyed from spring until late fall.
Low Growing Summer Blooming Perennial Flowers
When the heat of summer makes the blooms of the annual border plants droop, low growing summer perennial flowers burst into bloom to keep the garden looking fresh, vibrant and well cared for.
Sweet William and thrift are low growing perennials that bloom from the middle of May until August, when the fall flowers come into bloom. Seldom growing over 12 inches high, sweet William comes in a wide range of colors, and the tiny thrift is available in white and rose. The fuzzy lamb's ears also blooms in the summer, and is available in many colors. The texture of the leaves makes the lamb's ears a point of interest all year long.
Medium Summer Blooming Perennials
Waves of continuing color and texture depend on the proper balance of height in the garden. Plants with flowers that reach from 18 inches to just over 3 feet are considered medium blooming perennials.
Astilbe, columbine, lavender, baby's breath, phlox, the oriental poppy and Shasta daisy all grow to about 24 inches high and can be planted behind the low growing perennials for a summer show of color.
Coralbells and coreopsis reach about 18 inches, a height to give a gradual horizontal slope between the low growing border plants and the tall focal points.
Phlox, oriental poppy and columbine are all available in many colors. The coreopsis is available in yellow, while baby's breath and the Shasta daisy add the coolness of white to the garden.
Tall Summer Blooming Perennials
Draw the eye upward by planting tall flowers in the garden. Foxglove, delphinium and lilies grow about 4 feet tall and are all available in many colors. Plant the tall perennials along the back boundary of the garden, or in the center of a garden that can be seen from all angles.
Poker plants can be found in white, yellow or red and usually reach a height of 3 feet. The blue globe thistle reaches a height of approximately 40 inches, while the lythrum, available in red, pink or purple, grows to 4 feet.