15 Cool-Season Flowers You Should Plant Now

Cool-season flowers extend the garden’s bloom time as summer winds down, and many of them are perfect for planting NOW (in late summer and early autumn). They flourish in moderate temperatures and bridge the gap between hot and cold conditions. Depending on your climate and anticipated first frost date, late summer and early fall are prime for planting cool-season annuals to establish them for fall flowering.

Cold-tolerant annuals benefit from the long, frost-free days of late summer to develop roots before freezing temperatures. Before planting, ensure enough time before frost to enjoy mature flowers. Check your estimated first frost date. Starting with nursery bedding plants is a good idea for quick establishment. If starting fast-growers from seed, count out the days to maturity in relation to the initial frost.

Calendula

	common name Calendula
	botanical name Calendula officinalis
	sun requirements Full sun
	height 2’
	hardiness zones 2-11

Calendula has sunny daisy flowers in yellow, orange, pink, and bicolor. Its single or double blooms brighten chilly days and have a long bloom time.

Calendula grows best in fall and spring and even over the winter in warm climates. The flowers emerge from spring to frost in cool climates, taking a break in high summer heat.

Calendula flowers quickly from seed, with buds opening in about 30 days. Direct sow seeds if you have time before your first frost date to relish the versatile flowers. Calendula leaves and flowers are edible and make a beautiful dried floral addition. Plants may self-sow for a spring bloom.

Diascia

	common name Diascia
	botanical name Diascia barberae
	sun requirements Full sun
	height 10-12”
	hardiness zones 8-11

Diascia is a sweet addition to the cool-season border or container. Its delicate flowers blanket mounding foliage. Slender stems hold pure white, pink, bright red, and orange blossoms.

This is a vigorous, cold-tolerant annual. In the snapdragon family, it has larger, looser, tubular flowers than snaps. It is rising in popularity and many hybrids are available. The ‘Whisper’ series is larger in stature among the group and includes harvest colors like ‘Pumpkin’ and ‘Cranberry.’

Feature diascia as a single specimen in containers or pair it with other cool-season growers. Plants tolerate freezing temperatures once established. They stop flowering if stressed by cold. Growing temperatures to establish are optimal at 50-75°F (10-24°C).

Snapdragon

	common name Snapdragon
	botanical name Antirrhinum majus
	sun requirements Full sun to partial shade
	height 6-36”
	hardiness zones 7-10

Snapdragons are quintessential cool-season flowers with showy plumes in saturated hues. They make beautiful cut flowers and, in moderate climates, survive winter temperatures in the garden or containers. 

In mild winter climates, snaps bloom from autumn through spring. In colder climates, they flower in spring, summer, and fall.

Snapdragons take 60 to 80 days to mature from seed. Opt for nursery starts in short growing seasons. In late summer, start seeds indoors in hot climates. They flower almost year-round in mild conditions. Once established, snapdragons tolerate subfreezing temperatures. Keep them evenly watered to survive freezing. Plants are hardy to 25°F (-4°C) and perhaps lower with mulch and protection.

Remove spent blooms to keep the plant from going to seed and to promote continued blooming. Pair them with pansies, violas, ornamental kale, and Swiss chard for an autumnal arrangement.

Violas & Pansies

	common name Violas & Pansies
	botanical name Viola spp.
	sun requirements Full sun to partial shade
	height 6”
	hardiness zones 3-8

Pansies and violas survive winter in mild climates and withstand seasonal transitions in colder climates. In northern climates, grow them for a fall or spring display. Like snapdragons, pansies, and violas flower reliability in chilly temperatures and withstand frost. 

The annuals’ petite bloom faces in a wash of colors and combinations create an instant display. Use them in a mass at the front of the border or tuck them into containers and window boxes for multi-season appeal. Opt for trailing pansies for delicate blooms that spill over a pot.

These tough annuals tolerate cold spells with temperatures around 20°F (-7°C, and sometimes lower, depending on conditions). Leaves may turn gray during cold snaps and recover as temperatures warm.

Wallflower

	common name Wallflower
	botanical name Erysimum spp.
	sun requirements Full sun to partial shade
	height 1-3’
	hardiness zones 5-9

Wallflowers don’t shy away from the cool-season display. They tolerate moderately hot and cold conditions, making them good transitional-season growers. Enjoy them as fall annuals, or in warm climates where frost is absent, sow seeds to establish over the winter for a spring bloom.

Erysimum has clusters of velvety petals in vintage orange, purple, pink, and scarlet shades. Leafy stems hold long, narrow foliage in deep green. Florets have a honey fragrance and appeal to pollinators.

Wallflowers grow easily in well-drained soils. They remain evergreen in warm zones and die back with prolonged cold exposure.

Foxglove

	common name Foxglove
	botanical name Digitalis purpurea
	sun requirements Full sun to partial shade
	height 2-5’
	hardiness zones 4-9

Now is the time to think about a spring show of foxgloves in moderate-growing areas. Foxgloves are cold-hardy biennials that bloom in spring and summer in cool climates. They’ll establish over the winter in warm temperatures for a late spring bloom display. 

Foxgloves produce an abundance of bell flowers on tall, sturdy stems in colors ranging from rose to creamy white to lavender. Pollinators find them irresistible, especially early in the season, as heat-loving flowers aren’t yet blooming.

In mild climates, surface-sow Digitalis seeds in early fall or start them from plugs or nursery pots to establish before frost. Foxgloves grow best in consistently moist, organically rich soils with good drainage.

Sweet  Peas

	common name Sweet  Peas
	botanical name Lathyrus odoratus
	sun requirements Full sun to partial shade
	height 3-10’ vines
	hardiness zones 7-10

Ornamental sweet peas enchant with colorful blooms on twining vines. Flowers carry an intensely sweet perfume and come in a variety of colors like pink, mauve, red, blue, peach, and white. While sweet peas are popular spring growers, they also thrive in fall’s cool weather.

The frost-tolerant beauties grow quickly from seed. Direct sow them or transplant potted seedlings to enjoy before heavy frost. Give them a good soak and slight scarring before planting. Ideal growing temperatures are between 55 and 65°F (13-18°C).

Sweet peas cling and climb; for best growth, they need a support structure like a tripod or trellis. Use them as a container focal point for vertical interest. Dwarf varieties quickly reach two to three feet and don’t require support.

Stock

	common name Stock
	botanical name Matthiola incana
	sun requirements Full sun to partial shade
	height 1-3’
	hardiness zones 6-10

Stock is a nostalgic favorite with fragrant, jewel-tone flowers on stiff, upright stems. It features single or double white, red, purple, cream, and copper flowers. Stock makes a lovely cut flower with a scent to savor.

Stock thrives and blooms best in cool temperatures. It doesn’t withstand hot summers or frigid winters. It blooms from spring through frost as a tender perennial in cool climates and as a cool-season annual across zones. Stock is hardy to 25°F (-4°C).

Stock grows easily from seed, usually germinating in seven to ten days. Established plants tolerate periods of light frost. Stock does best in highly organic and well-draining soils, though it withstands occasional wet soils.

Sweet Alyssum

	common name Sweet Alyssum
	botanical name Lobularia maritima
	sun requirements Full sun to partial shade
	height 3-10”
	hardiness zones 5-9

An excellent companion plant, sweet alyssum is a small annual with a profusion of white, pink, or purple pincushion blooms in cool seasons. Its sweet fragrance and numerous flowers overcome its diminutive scale. They’re showy and attract pollinators.

The dainty annuals are tough and hardy down to 20°F (-7°C). Sweet alyssum self-seeds and volunteer seedlings may pop up in the spring. 

In the heat of summer, plants turn yellow and fade but resume blooming with cooler temperatures. They’ll die out in southern climates but recover in northern growing regions.

African Daisy

	common name African Daisy
	botanical name Osteospermum spp.
	sun requirements Full sun to partial shade
	height 1-3’
	hardiness zones 10-11

African daisies welcome cool weather with a swirl of ray petals in white, pink, purple, coral, yellow, and bicolor. They spark whimsy in flower shape and form, from upright to trailing.

Osteospermum is cold-hardy to 25°F (-4°C). In climates with cool summers, it flowers from spring until frost. In warmer climates, it does best in autumn and spring before higher temperatures arrive.

African daisies make a beautiful cut flower. Selections in autumnal or jewel tones highlight the arrangement before prolonged freezing conditions.

Bachelor’s Button

	common name Bachelor’s Button
	botanical name Centaurea montana
	sun requirements Full sun to partial shade
	height 1-2’
	hardiness zones 3-8

Bachelor’s button (also cornflower) is a perennial that prefers cool and moderate conditions to flourish. It flushes in late spring and early summer with a light repeat bloom in fall. The flowers are wispy lavender-blue petals that surround rose-purple centers. In hot summers, Centaurea fades.

C. cyanus is an annual cornflower with rich blue, ruffled flowers atop upright stems. It grows easily from seed, producing fall flowers with a late summer sowing. In warm growing areas, it blooms through winter. Be careful planting this one, though. It is invasive in several states.

In optimal conditions, especially in northern climates, cornflower spreads aggressively. Deadhead blooms to prevent seeding and divide perennial colonies every few years.

Dianthus

	common name Dianthus
	botanical name Dianthus chinensis
	sun requirements Full sun to partial shade
	height 6-30”
	hardiness zones 6-9

The annual dianthus bears an abundance of flowers and a sweet fragrance. The blossoms have flat, open faces with fringy edges. Petals in pink, red, rose, lavender, and white darken around the central eye. Slender stems hold the flowers above narrow, lanced foliage.

Annual “pinks” are rugged beauties that tolerate light frost and continue to bloom. Plants may self-sow, though seedlings won’t be true to type if the parent is a hybrid (likely in annual selections). Deadhead dianthus to promote flowering.

Purchase annual dianthus from your garden center for fall growing, or take cuttings from your spring selections. Annual pinks propagate through vegetative cuttings, and the established growth allows more extended autumn blooming.

Flowering Kale

	common name Flowering Kale
	botanical name Brassica oleracea
	sun requirements Full sun to partial shade
	height 10-15”
	hardiness zones 2-11

Ornamental kale is a must-have in autumnal planting arrangements. Depending on your climate, kale survives all winter or performs best in fall and early spring.

Thick, colorful leaves with ruffly edges create textural variety. Flowering kale is grown not for its flowers or edible qualities but for its rosette cabbage heads in green, creamy white, and deep pink. 

The ‘Lucir’ and ‘Crane’ series have cabbage leaves that resemble ornamental flowers. Small rosettes top long, sturdy stems. Underplant with annuals to soften the stems, creating a floating floral effect.

Arrange flowering kale with other leafy vegetables, such as bright lettuces and Swiss chard varieties with colorful stems and rich leaves. They make wonderful snapdragon, pansy, and viola accents.

Love-in-a-Mist

	common name Love-in-a-Mist
	botanical name Nigella damascena
	sun requirements Full sun
	height 1-2’
	hardiness zones 10-11

Love-in-a-mist has delicate, feathery foliage and airy flowers surrounded by “misty” bracts. Deeply cut petals are blue, pink, white, or lavender. Long, dark seed pods extend interest post-bloom.

Nigella performs best as a fall or spring annual and wilts in hot conditions. Sow seeds in late summer or fall for seedlings to overwinter. They’ll establish sturdy root systems for larger, earlier-flowering plants in the spring.

Love-in-a-mist spreads readily via self-seeding. Deadhead spent blooms and remove seed pods before they drop to prevent unwanted spread.

Nasturtium

	common name Nasturtium
	botanical name Tropaeolum spp.
	sun requirements Full sun to partial shade
	height 1-10’
	hardiness zones 9-11

Nasturtium relishes the mild temperatures of fall, making it a good fit for harvest-themed plantings and loose, natural, edible compositions. Its round leaves and large tubular flowers are edible, with a spicy, peppery taste. Nasturtiums make a pretty garnish for fall salads and platters.

A late summer round of bright blooms draws pollinators until freezing temperatures. They proliferate from seed but won’t withstand heavy frost.

Use nasturtium as a single display with climbing or trailing stems, or pair it with marigolds, salvia, flowering kale, and ornamental grasses. Nasturtiums are easy-to-grow annuals in beds, hanging baskets, window boxes, and containers. Grow them in your kitchen garden to ward off pests.