Herbaceous perennials are valuable in the container garden. In planters, raised beds, and large boxes, they contribute greatly to the garden design with their distinctive foliage and attractive flowers. As a group, perennials are adapted to a variety of conditions, tolerating sun or shade, moist or dry locations. For the most part, they are hardy, but some require winter covering.
Select some perennials with good all-season foliage. When daylilies, peonies, phlox, coral-bells, gas plant, astilbe, and hardy candytuft finish flowering, their leaves remain attractive. With Oriental poppies, bleeding hearts and primroses, the leaves turn yellow once blooming is over, though this does not mean they are undesirable. Bare spots left by them can be concealed by other plants like quick-growing annuals.
Perennials like daylilies and iris thrive where it is hot; lupines, delphiniums, and astilbes prefer cooler temperatures. You can have some biennials, too-foxgloves, canterbury-bells, sweet williams and verbascums-and discard them after flowering.
Today, nurserymen and garden centers offer mature perennial and biennial plants in tins, baskets, tar paper, papier-mache, and other temporary containers. They provide for quick, colorful effects.
Acanthus or Bear's Breech. Tall and striking from southern Europe, whose leaf the ancient Greeks adapted for the capitals of Corinthian columns. Arching, deep-cut, thistlelike leaves, two feet long, shining dark green, are surmounted with tall, white, rose-tinged spikes. Give plants large pots with good drainage and full sun. Not hardy in the North where they need winter protection.
Asters. Handsome with starry blossoms for rich purple, lavender, rose, pink, and white autumn displays. Many varieties vary from nine inches to four or more feet. Plants need full sun and respond to feeding and watering, but are otherwise easy. They are best divided each spring.
Bearded Iris. Number one favorite, beloved for its exquisite blooms in rainbow colors. Hardy and easy to grow, spearlike leaves provide accent among other plants. Clumps need dividing every third year. Borers can be
controlled with repeated DDT sprayings, starting in early spring.
Chrysanthemums. Free-flowering and invaluable for the pot garden. With these alone, you can enjoy riotous color from August even to December. Grow your own or buy plants in bud from commercial growers. They move easily when in bloom, if you take care to keep them moist. After flowering, plant in garden or cold frame and give winter protection or discard the roots like annuals.
Daylilies or Hemerocallis. Thriving in hot and cold climates, in shade or full sun. Straplike foliage remains attractive all season. For warmer regions there are evergreen varieties. Trumpet flowers, mostly yellow and crimson, open over a long period, even though each bloom stays fresh but one day. The Greek name, hemerocallis, means "beautiful for a day."