The very best summer annuals combine a number of traits: They withstand heat, are free-flowering, do not need frequent maintenance, have a long blooming period and have clear, attractive colors. For flower gardens, you want an assortment of development forms — low plants to the front of the bed and also to spill over edges, plants of medium height that can function as boundaries, tall plants that can form background plantings or screens. Plant breeders consistently come up with new varieties of annuals that improve on old favorites.
Low-Growers
For open, sunny, hot areas, among the very best summer annuals is moss rose (Portulaca grandiflora), together with succulent leaves and showy, 1-inch-wide dual or single flowers in tones of crimson, pink, yellow and orange. Growing 6 inches tall, the plant requires little to no upkeep. Although it’s grown as an annual, it’s hardy in U.S. Department of Agriculture plant hardiness zones 5 through 11. The Supertunia series of petunias (Petunia hybrida) provide mounded increase to 8 or 12 inches tall, and spill over bed edges. They are hardy in USDA zones 10 through 11. Supertunias do not need deadheading. They come in vivid colors, including “Pretty Much Picasso,” with purple flowers rimmed in chartreuse.
Wallpapers and Screens
Two members of the sunflower family grow tall enough for desktop plantings and densely enough to supply a display. The bright orange-red shade of Mexican sunflower (Tithonia rotundiflora) tops stems of 5- to 6-foot-tall, large-leaved plants. Grown in USDA zones 4 through 10 in sun or partial shade, they make good cut flowers. Adaptable to a lot of soil and climate types, annual sunflower (Helianthus annuus) contains numerous cultivars appropriate for flower arrangements with bright blossom colors on branching plants that rise from 4 to 8 feet tall, depending on the cultivar. For instance, “Autumn Beauty” has yellow, purple, bronze and bicolored blooms, on a plant 5 to 7 ft. “Sunburst Mixed” grows about 4 feet tall and produces blooms in gold, bronze, lemon and crimson.
Borders and Bulk Plantings
For mass plantings and borders, branching development and abundant, long-flowering annuals are best. A zinnia (Zinnia elegans) cultivar with exceptional branching growth habits, Distance mixture zinnias grow 12 to 16 inches tall with semi-double blooms up to 3 1/2 inches wide. Flower colors are yellow, red, purple, orange and white. Several other zinnia cultivars in different plant heights, flower sizes and colors are available. A plant that is so suited to hot summer weather that you want to be careful not to overwater it for best growth, yellow cosmos (Cosmos sulphureus) blooms from May to September. Cultivars grow from 2 to 4 feet tall with good branching and long, narrow-lobed leaves. Some cultivars to believe are “Crest Red,” “Ladybird Dwarf Orange” and “Klondyke Mix.” Both zinnias and cosmos make good cut flowers.
Long-Lasting Flowers
Members of the amaranth family have flower heads consisting mostly of papery bracts that could last for weeks rather than a day or two. The feathery blossoms of plumed celosia (Celosia argentea var. Plumosa) come in hues of pink, crimson, yellow and orange. The plants grow 6 to 36 inches tall, depending on the cultivar. Offering smaller but abundant across flower heads, globe amaranth (Gomphrena globosa) rises 1 to 2 feet tall. Little, white to yellowish flowers have brightly colored bracts that give the blossom cluster shape and colour. Numerous cultivars produce pink, red, magenta, white, violet or purple flower heads. Use celosia and globe amaranth in fresh and dried floral arrangements.