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If your perennial garden starts to fizzle as soon as hot weather arrives, then you need a plan to keep your beds blooming. Try interplanting your perennials with annuals that love hot weather. You can experiment each season until you find combinations that suit you, your garden, and your climate.
Amaranthus (amaranth)
18 in. to 6 ft., varies with species
Red, orange, gold, green, purple
Notes: Resents transplanting. Direct-seed.
Can't Tolerate: Wet soil; shade
Arctotis hybrids (African daisy)
1 ft. to 2 ft., varies with cultivar
Red, pink, orange, yellow, white
Notes: Direct-seed after frost.
Can't Tolerate: Humidity; high night temps
Catharanthus roseus (Madagascar periwinkle)
4 in. to 24 in., varies with cultivar
Red, pink, lavender, white
Notes: Difficult to start from seed. Buy plants instead.
Can't Tolerate: Temps below 60 degrees F
Celosia spicata (wheat celosia)
2 ft. to 4 ft., varies with cultivar
Red, pink, purple
Notes: Good cut flower, fresh or dried.
Can't Tolerate: Cold soil; cold water
Cleome hassleriana (spider flower)
3 ft. to 5 ft.
Rose, pink, purple, white
Notes: Easy to grow from seed; self-sows.
Can't Tolerate: No problems
Cosmos bipinnatus 2 ft. to 5 ft., varies with cultivar
Crimson, pink, white
Notes: Easy to grow from seed; self-sows.
Can't Tolerate: Rich soil (yields few flowers)
Cosmos sulphureus 1 ft. to 4 ft., varies with cultivar
Scarlet, orange, yellow
Notes: Easy to grow from seed; self-sows.
Can't Tolerate: Rich soil (yields few flowers)
Cuphea micropetala (cigar plant)
3 ft. to 4 ft.
Red
Notes: Buy transplants.
Can't Tolerate: No problems
Eschscholzia californica (California poppy)
6 in. to 15 in.
Red, pink, orange, yellow, cream
Notes: Resents transplanting. Sow seed; deadhead for continuous bloom.
Can't Tolerate: Rich soil; wet soil
Euphorbia bicolor (snow-on-the-prairie)
18 in. to 24 in.
White bracts
Notes: Milky sap is toxic. Easy to grow.
Can't Tolerate: Rich soil (yields floppy stems)
Gazania hybrids 6 in. to 15 in., varies with cultivar
Red, pink, bronze, orange, yellow
Notes: Good for hot, windy spots.
Can't Tolerate: Rain; wet soil; humidity
Gomphrena (globe amaranth)
12 in. to 30 in., varies with cultivar
Rose, orange, purple, lavender, white
Notes: Good cut flower, fresh or dried.
Can't Tolerate: Cold soil; poor air circulation
Ipomoea quamoclit (cypress vine)
6 ft. to 25 ft.
Scarlet
Notes: Resents transplanting. Easy to grow from seed; self-sows.
Can't Tolerate: No problems
Lantana 1 ft. to 6 ft., varies with species
Red, pink, orange, cream, lilac, purple, white, and bicolors
Notes: Buy transplants. Berries are toxic; look for nonfruiting varieties.
Can't Tolerate: Rich soil; night temps below 60 degrees F
Melampodium paludosum (medallion flower)
8 in. to 24 in.
Yellow
Notes: Good for hot, humid climates; very tough plant.
Can't Tolerate: Rich soil; wet soil
Mirabilis jalapa (four o'clocks)
2 ft. to 3 ft.
Red, pink, salmon, yellow, white
Notes: All parts of plant are poisonous. Best direct-sown; self-sows.
Can't Tolerate: No problems
Nicotiana (flowering tobacco)
8 in. to 5 ft., varies with species
Rose, pink, green, purple, white
Notes: Easy to grow from seed. Some types fragrant; some will self-sow. Can't Tolerate: Wet stems and leaves (water from below)
Petunia 6 in. to 24 in., varies with cultivar
All colors
Notes: Deadhead for continuous bloom.
Can't Tolerate: Humidity; frequent rain
Portulaca (rose moss)
4 in. to 8 in.
Red, magenta, pink, salmon, orange, yellow, white
Notes: Easy to grow from seed; rooted cuttings will overwinter.
Can't Tolerate: Humidity
Sanvitalia procumbens (creeping zinnia)
4 in. to 8 in.
Orange, yellow
Notes: Performs in partial shade, but plant close together for fullness.
Can't Tolerate: Poor drainage
Tagetes (marigold)
6 in. to 4 ft., varies with species
Maroon, orange, yellow, cream
Notes: Easy to start from seed. Deadhead for continuous bloom.
Can't Tolerate: Rich soil
Thymophylla tenuiloba or Dyssodia tenuiloba (Dahlberg daisy)
4 in. to 8 in.
Yellow
Notes: Short-lived, but reseeds.
Can't Tolerate: Poor drainage
Tithonia rotundifolia (Mexican sunflower)
30 in. to 8 ft., varies with cultivar
Orange, yellow
Notes: Shrublike in growth. Deadhead for continuous bloom.
Can't Tolerate: Rain; rich soil (yields floppy stems)
Verbena peruviana (Peruvian verbena)
3 in. to 6 in.
Red, pink, white
Notes: Good as groundcover and on slopes; performs in partial shade.
Can't Tolerate: Wet soil
Verbena tenuisecta (moss verbena)
8 in. to 12 in.
Pink, lavender, purple, white
Notes: Shear plants to 2 in. tall if they become leggy.
Can't Tolerate: Poor drainage
Zinnia angustifolia (narrow-leaved zinnia)
12 in. to 15 in.
Orange, yellow, white
Notes: Mildew-resistant.
Can't Tolerate: No problems
Zinnia elegans (common zinnia)
4 in. to 4 ft., varies with cultivar
All colors except blue
Notes: Easy to grow from seed. Deadhead for continuous bloom.
Can't Tolerate: Wet soil; poor air circulation
Since all of these plants are annuals or frost-sensitive perennials, no zone information is given. Some of these plants perform better in certain conditions, however, so check under "Can't Tolerate" for specific dislikes. All need full sun to flower well. Keep in mind that some of these plants can be aggressive self-sowers or may be listed as invasive in warmer regions. Check with your local Cooperative Extension office or the USDA Web site http://plants.usda.gov/ for a list of plants that are invasive in your area.
