17 Flower Seeds to Plant in March

Seed starting is a rewarding process. You watch tiny seeds germinate, sprout, and grow into mature seedlings. Flowers are especially rewarding, as you can use them in bouquets, pollinator gardens, or decorations.

Annuals and perennials grow from seed. It’s a good idea to grow a mix of both, so your garden has plants that return in spring and space for different annuals. I like to grow perennial milkweed everywhere, and I tuck annuals like poached egg plants and balsam in the empty spaces. By summer, the garden is bursting with colors and aromas! 

Balsam

	botanical name Impatiens balsamina
	sun requirements Full sun to partial shade
	height 6”-3’
	hardiness zones 1-13

Balsam, or garden balsam, grows as an annual during the warm seasons. It’s frost tender, dying as soon as cold temperatures and frost arrive in fall and winter. It shines in the summer as it produces dozens of pink, red, and white blooms on erect stems. The stems bend in the shade, creating a lovely arching shape. 

It’s best to start balsam indoors in pots six to eight weeks before your last average frost date. This falls in March for most growers. Adjust the starting date to match your growing season, giving the seedlings a month or more to grow indoors. Harden them off for two weeks before transplanting—they’ll be ready for the outdoors in late spring or early summer.

Castor Bean

	botanical name Ricinus communis
	sun requirements Full sun
	height 6-10’
	hardiness zones 8-11

Castor bean is a highly poisonous but gorgeous flowering specimen! Originating from parts of eastern Africa, this ornamental species naturalized itself in parts of California and Florida. It sprouts maroon-purple leaves, yellow blooms, and bright red seed pods with spikey tendrils. 

Avoid planting castor beans in tropical areas of the U.S. where they can reseed. They’ll spread outside the garden and threaten native vegetation in wild spaces. If you live in these areas, cut off the seed pods before they open up to prevent the plant from self-sowing. The seeds are poisonous and the leaves may cause dermatitis. Use gloves when handling the plant to keep yourself safe. 

In USDA hardiness zones 8 and below, castor bean performs well as an annual flowering plant in sunny locations. Try ‘Impala’ for its medium-sized stature; it reaches six feet tall rather than ten. 

China Aster

	botanical name Callistephus chinensis
	sun requirements Full sun to partial shade
	height 2-3’
	hardiness zones 2-11

China asters decorate beds and borders with lacy foliage and bright-colored blooms! Many varieties and cultivars exist, offering flowers in purple, pink, white, and peach. Some have a single row of petals on their blooms, while other flashy types have two or more rows.

China asters aren’t like our native American asters—they’re frost-tender and grow as annuals during the warm seasons. Sow these flower seeds indoors a month or two before the final spring frost—around March for zones 5 through 8—and transplant them outdoors after the date.

Coleus

	botanical name Coleus scutellarioides
	sun requirements Full sun to full shade
	height 6”-3’
	hardiness zones 10-11

Coleus plants sprout flowers, though many gardeners grow them for their colorful, flashy foliage! The leaves come in many varieties, with variegated, red, green, pink, or yellow types. Some have ruffled edges, while others sprout leaves longer than six inches!

Coleus plants are tender perennials, meaning they’ll die if they suffer frost damage. Grow them as annuals to add color to shady areas of your yard. The plants will grow year-round in warm climates; clip them back each year to keep them bushy and bright.

It’s best to sow coleus flower seeds a month or two before your final frost, around March or April for most temperate growers. Plant them indoors in pots with humidity domes, or winter sow them in jugs. They need high humidity levels to germinate. After germination, remove the humidity domes and place the seedlings under filtered light until they’re ready for transplanting. 

Delphinium

	botanical name Delphinium spp.
	sun requirements Full sun to partial shade
	height 1-6’
	hardiness zones 3-9

Delphiniums, or larkspurs, decorate floral bouquets each year for weddings, Easter, and Valentine’s Day. Many are native to the U.S., thriving in meadows, prairies, and woodlands. They grow long, slender flowering stalks with dozens of blooms. Most types have purple or blue blossoms, though hybrids and cultivars offer a wider selection. 

For purple, pink, white, and blue blooms, choose a selection like the ‘Pacific Giants Blend.’ This mix has award-winning blossoms on giant stalks that reach up to six feet tall! Though hybrids are beautiful, it’s a good idea to plant native delphiniums in your yard like Delphinium nuttallianum or Delphinium carolinianum. They offer more rewards for local animals than non-native species.

To start delphiniums, sow them indoors eight weeks before frost dissipates from your region. Transplant the mature plants in early spring as days lengthen and the weather warms. 

Mexican Sunflower

	botanical name Tithonia rotundifolia
	sun requirements Full sun
	height 3-8’
	hardiness zones 2-11

Mexican sunflowers aren’t true sunflowers, though their small blooms resemble them! They’re both annuals in the aster family, Asteraceae, but Mexican sunflowers belong to the genus Tithonia, while true sunflowers belong to Helianthus.

Bees and butterflies love this species almost as much as we gardeners do! They sprout bold red-yellow blossoms on tall, fleshy stems that may reach eight feet in the air. The flower buds and petals are edible, working well in fresh dishes. They add a pop of flavor that’s bittersweet like how violets are. 

This Central and South American native plant prefers warm temperatures and frost-free weather. Grow it as a summer annual, sowing seeds indoors in March. Bring the ready plants outdoors a week or two after frost disappears from your region.

Milkweed

	botanical name Asclepias spp.
	sun requirements Full sun
	height 2-6’
	hardiness zones 3-10

Milkweed is the native plant you need in your yard! Its blooms, leaves, and stems support native butterflies that need habitat space. The plants offer nectar and pollen for adults, and food for the caterpillars as they emerge from eggs. The best milkweeds for your garden are local species that grow wild. 

West Coast growers should opt for narrowleaf or showy milkweed, while East Coast and Midwest gardeners can choose butterfly flower, swamp milkweed, or common milkweed. 

Milkweed is an excellent candidate for winter sowing, as the seeds have a necessary cold stratification period they must endure before sprouting. Winter sow them and the plants will naturally undergo a proper cold period. 

Purple Mullein

	botanical name Verbascum phoeniceum
	sun requirements Full sun
	height 2-4’
	hardiness zones 6-10

Purple mullein is a close relative of common mullein, the herbal perennial that grows wild throughout the U.S. This species sprouts thin, green stems with mullein-like blossoms in various purple shades. The hues look spectacular next to delphiniums, milkweeds, and asters in borders and raised beds.

Because Verbascum species are often invasive in our states, it’s better to grow a cultivar or hybrid that spreads less than a species type. Try ‘Shades of Summer’ for a mix of blossoms with white and purple. Sow seeds outdoors or indoors—plant these flower seeds indoors in March, or outdoors a month before the final frost date in your area. 

Sweet Annie

	botanical name Artemisia annua
	sun requirements Full sun
	height 4-6’
	hardiness zones 6-10

Sweet Annie is a close relative of wormwood with many similarities. It’s an herbal annual with aromatic foliage that repels moths while simultaneously luring pollinators. It sprouts white-yellow clusters of small flowers on long stems. 

Most flower lovers grow this species to make dried arrangements. The dry leaves and flowers hold their color well and retain their fragrance for many months! 

This annual grows best from inside starts. Sow sweet Annie flower seeds in pots around March, or two months or more before the last frost. Keep them well-lit and sufficiently moist and they’ll sprout 10 to 20 days after planting.

Outdoor

Outdoor seed starting is simpler than indoor sowing. Simply scatter seeds, bury them at the proper depth and keep them moist. They’ll germinate when it’s the best time for them to do so. 

Patience is key, as many plants wait to germinate until outdoor temperatures are in an optimal range. Have patience when sowing these flower seeds in March—they’ll sprout when ready! 

Columbine

	botanical name Aquilegia spp.
	sun requirements Full sun to partial shade
	height 1-3’
	hardiness zones 3-9

Many columbines are native plants in the U.S., essential for bees, moths, and butterflies. Some originate from Europe, though nowadays hybrid cultivars exist with both European and American parent plants. Their flowers offer valuable nectar in their spurs, luring insects with long-reaching mouthparts into their centers. There, they exchange pollen for nectar. 

Many columbines grow only in certain states, sprouting in small, localized regions. They prefer well-draining soil, regular moisture, and lots of direct sunlight. Surface sow them four to six weeks before the last frost. They’re drought tolerant after they establish themselves.

Gazania

	botanical name Gazania rigens
	sun requirements Full sun
	height 6-12”
	hardiness zones 9-11

Pollinator-friendly and delightfully colorful, gazanias are one of the best perennial flower seeds you can plant during March. Orange, yellow, white, and red hues decorate three to four-inch sunflower-like blossoms. They attract beneficial pollinators, and they sprout high above the low-growing foliage. 

Though gazanias are perennial in zones 9 through 11, they grow well as annuals in colder regions. Winter sow the lazy way by planting gazanias a quarter inch deep in well-draining soil. Keep them moist, and they’ll germinate when outside temperatures are optimal. 

Lavender

	botanical name Lavandula spp.
	sun requirements Full sun
	height 1-3’
	hardiness zones 5-9

Lavender flowers form off green, fleshy stems that grow woody as they mature. The blooms are purple, ornamental, and incredibly fragrant. The smell soothes anxious minds, offering a natural relief from tension. Infuse the blossoms in oils, make arrangements, or blend them with other herbs in a potpourri. 

Lavender seedlings can have spotty germination rates, so it’s best to sow two or three seeds per hole to ensure even growth. Lightly cover them with one-eighth inch of soil, then water them well. You may plant lavender as soon as the soil can be worked in late winter or early spring. 

Pansy

	botanical name Viola x wittrockiana
	sun requirements Full sun to partial shade
	height 4-9”
	hardiness zones 6-10

Edible flowers are indispensable in the garden. They have ornamental and functional uses, and you can put them in your veggie garden or floral borders—they’re versatile! Pansies are one of the best species with edible blossoms. They’re frost tolerant, blooming for four to six months despite recurring frosts.

Pansies grow best in early spring or fall when the weather is cool, mild, and moist. They’ll suffer as summer arrives, as the heat zaps their petals and leaves. Use them as bedding materials or tuck them amongst veggies, herbs, and other flowering species. 

Penstemon

	botanical name Penstemon spp.
	sun requirements Full sun to partial shade
	height 1-4’
	hardiness zones 3-9

Penstemons, or beardtongues, are a diverse group of native and non-native species. They form long, slender flowering stalks with bell-shaped flowers. They resemble foxglove blooms, with open lips and spots on their throats. Find penstemons with rose, pink, blue, and lavender blossoms. ‘Dazzler Blend’ has a mix of all four!

Surface sow penstemons a month or two before the last frost date in your region. Keep the site moist, not soggy, and wait for seedlings to emerge. They’ll sprout anywhere from 14 to 35 days after they received the required cold period. 

Poppy

	botanical name Papaver spp.
	sun requirements Full sun to partial shade
	height 3-5’
	hardiness zones 2-10

Poppies are longtime favorites of gardeners and farmers. Their sun-loving petals decorate open fields in summer. They can be found in shades of purple, red, orange, pink, and white—the possibilities are endless! They grow worldwide, from North America to Eurasia and Africa. 

Easy growing and fun to plant, poppies are essential additions to the flower garden. Try ‘Hungarian Blue’ for lovely hues of rosy purple, or ‘Black Swan’ for ruffly maroon petals. Rake the seeds on the soil’s surface as soon as the ground is workable in late winter and early spring. March is often the perfect month for planting these flowers, as there is still some cold to help the seeds germinate!

Sweet Pea

	botanical name Lathyrus odoratus
	sun requirements Full sun to partial shade
	height 4-6’
	hardiness zones 7-10

Sweet peas are close relatives of the edible peas, though they’re grown exclusively for their blossoms. Like peas, sweet pea flowers have two-lipped portions that meet in the middle. Pollinators open the lips, crawl inside, and gather pollen or nectar. 

You’ll find this species in all shapes and sizes. Maroon, red, pink, blue, white, peach, and purple cultivars exist. ‘Beaujolais’ resembles ‘Black Swan’ poppies in color, with maroon-black hues on the lipped petals. Opt for a mix like ‘Bouquet Blend’ for a mixture of all the colors. No matter which variety you choose, you can’t go wrong with sweet peas. 

To plant, sow sweet peas a month or more before the final frost, as soon as you can work the soil. Bury them an inch deep and keep them sufficiently moist until they emerge. You’ll see seedlings sprouting 10 to 21 days later.

Viola

	botanical name Viola spp.
	sun requirements Full sun to full shade
	height 4-12”
	hardiness zones 1-10

Violas, or violets, decorate cottage and woodland gardens throughout the world. They’re iconic flowering species—many are beneficial for pollinators, some are easy growing, and others are edible! No matter what your growing preferences are, there’s sure to be a viola for you.