Want to get a head start on next year’s stunning flower garden? A study by the Royal Horticultural Society found that September sowings of hardy annuals resulted in up to 70% larger plants than those sown in spring.¹
By planting now, you allow the seeds to establish strong roots before winter, giving them a jump on the growing season.
Here are the 12 best flowers to start from seed this month for a beautiful display next year!
1. Cornflowers (Centaurea cyanus)
Cornflowers, or bachelor’s buttons, are true blue beauties that add a charming touch to any garden. These annuals are incredibly easy to grow and thrive in poor soil with minimal care.
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Sow cornflower seeds directly in a sunny spot in September for a slightly earlier appearance next summer. The delicate blooms belie the plant’s hardy nature, making them a reliable choice for zones 2-11.
You need to enrich the soil with compost or fertilizer at planting time and water during dry spells. Cornflowers attract pollinators and make excellent cut flowers, so plant plenty to enjoy in the garden and vases indoors.
2. Nigella (Nigella damascena)
Enchanting and whimsical, nigella, or love-in-a-mist, is a must-have for any cottage-style garden. These annuals feature delicate, lacy foliage and charming blue, pink, or white flowers that bloom throughout the summer.
Nigella grows from seed effortlessly and thrives in zones 2-11.
Sow nigella seeds directly in the garden in September, as they prefer to be planted in cooler temperatures. Choose a location with well-draining soil and full sun to partial shade.
Once established, nigella requires minimal maintenance and will often self-sow, providing you with years of carefree beauty.
3. Iceland Poppies (Papaver nudicaule)
Iceland poppies paint the garden in a mesmerizing array of colors, from soft pastels to vibrant oranges and yellows. These short-lived perennials are prized for their paper-thin, cup-shaped flowers that sway gracefully in the breeze.
While they can be challenging to grow from seed, the extra effort is worth it for their beautiful display.
Start Iceland poppy seeds indoors in September, as they require a period of cold stratification to germinate.
Sow the seeds in trays filled with seed compost and place them in a refrigerator or cold frame for 3-4 weeks before moving them to a warm, bright location. Transplant the seedlings outdoors in early spring for a stunning show in zones 2-7.
4. Forget-Me-Nots (Myosotis sylvatica)
Forget-me-nots are dainty, spring-blooming biennials that create a captivating carpet of blue, pink, or white flowers. These low-growing plants are perfect for edging, rock gardens, or naturalizing in woodland areas.
Forget-me-nots are effortless to grow from seed and thrive in zones 3-8. Sow forget-me-not seeds in the garden in September, as they require a cold period to germinate. Choose a location with moist, well-draining soil and partial shade.
Once established, forget-me-nots will self-seed readily, creating a charming, informal display year after year.
5. Foxgloves (Digitalis purpurea)
Foxgloves are majestic biennials or short-lived perennials that add vertical interest and old-world charm to any garden. Their tall spires of tubular flowers in shades of pink, purple, and white attract bees and hummingbirds.
Foxgloves can easily grow from seed and thrive in zones 4-8.
Start foxglove seeds indoors in September for blooms the following summer. Sow the seeds in trays filled with seed compost and keep them in a warm, bright location until they germinate.
Transplant the seedlings outdoors in spring, choosing a spot with partial shade and moist, well-draining soil.
Foxgloves will often self-seed, providing you with a continuous display of these stately beauties.
6. Sweet Peas (Lathyrus odoratus)
Sweet peas are enchanting annual climbers that captivate with their fragrant, butterfly-like flowers in a rainbow of colors. These old-fashioned favorites are a must-have for cutting gardens and cottage-style plantings.
While sweet peas can be challenging to grow from seed, the reward of their heavenly scent and romantic blooms is well worth the effort.
Sow sweet pea seeds in September, as they benefit from a cold period to encourage strong root growth.
Plant the seeds in deep pots or root trainers filled with well-draining compost and place them in a cold frame or unheated greenhouse over winter. Pinch the growing tips when the seedlings reach 4 inches tall to encourage bushiness.
Transplant the young plants outdoors in spring, supporting their twining stems.
7. Poppies (Papaver spp.)
Poppies are iconic wildflowers that add vibrant color to any garden. From the classic red corn poppy to the frilly, pastel-hued Shirley poppies, there’s a variety to suit every taste. Poppies can easily grow from seed and thrive in zones 3-9.
Sow poppy seeds directly in the garden in September. They prefer cool temperatures and well-draining soil. Scatter the seeds on the soil surface and lightly rake them in, as they require light to germinate.
Poppies will often self-seed, creating a natural, meadow-like display year after year.
8. Hollyhocks (Alcea rosea)
Hollyhocks are stately biennials or short-lived perennials that add height and old-fashioned charm to cottage gardens and borders. Their tall spires of saucer-shaped flowers in shades of pink, red, yellow, and white bloom from mid-summer to early fall.
Hollyhocks can easily grow from seed and thrive in zones 3-9.
Start hollyhock seeds indoors in September for blooms the following summer. Sow the seeds in trays filled with seed compost and keep them in a warm, bright location until they germinate.
Hollyhocks may require staking to support their towering stems.
9. Columbines (Aquilegia spp.)
Columbines are enchanting perennials that add a touch of woodland magic to any garden. Their delicate, spurred flowers in various colors, from soft pastels to rich jewel tones, dance on slender stems above lacy foliage.
Columbines can easily grow from seed and thrive in zones 3-9.
Sow columbine seeds in September, which require a cold period to germinate. Plant the seeds in trays filled with seed compost and place them in a cold frame or refrigerator for 3-4 weeks before moving them to a warm, bright location.
Transplant the seedlings outdoors in spring, choosing a spot with partial shade and moist, well-draining soil.
Columbines will often self-seed, creating a charming, naturalized display.
10. Delphiniums (Delphinium elatum)
Delphiniums are majestic perennials that add height and drama to any garden with their towering spires of blue, purple, pink, or white flowers. These cottage garden favorites bloom from early to mid-summer and make stunning cut flowers.
While delphiniums can be challenging to grow from seed, the extra effort is well worth it for their breathtaking display.
Start delphinium seeds indoors in September for blooms the following summer. Sow the seeds in trays filled with seed compost and keep them in a warm, bright location until they germinate.
Delphiniums require staking to support their tall stems and protection from slugs and snails.
11. Lupines (Lupinus spp.)
Lupines are striking perennials that add architectural interest and vibrant color to borders and cottage gardens. Their tall spires of pea-like flowers in shades of blue, purple, pink, yellow, and white bloom from late spring to early summer.
Lupines can easily grow from seed and thrive in zones 4-8.
Sow lupine seeds in September, as they benefit from a cold period to encourage germination. Plant the seeds in trays filled with seed compost and place them in a cold frame or refrigerator for 3-4 weeks before moving them to a warm, bright location.
Lupines attract pollinators and make excellent cut flowers.
12. Scabiosa (Scabiosa atropurpurea)
Scabiosa, or pincushion flowers, are charming annuals or perennials that add a touch of whimsy to any garden. Their dainty, pincushion-like flowers in shades of blue, purple, pink, and white bloom from summer to fall, attracting a host of pollinators.
It is easy to grow from seed and thrives in zones 3-7.
Sow scabiosa seeds in September, as they benefit from a cold period to encourage strong root growth. Plant the seeds in trays filled with seed compost and place them in a cold frame or unheated greenhouse over winter.
Transplant the seedlings outdoors in spring, choosing a spot with full sun and well-draining soil. Deadhead spent blooms regularly to encourage continuous flowering.
By sowing these flowers in September, you’ll set the stage for a color, texture, and fragrance display in next year’s garden.
So, grab your seed packets, and get ready to enjoy the fruits of your labor come spring!
Source:
Nancy has been a plant person from an early age. That interest blossomed into a bachelor’s in biology from Elmira College and a master’s degree in horticulture and communications from the University of Kentucky. Nancy worked in plant taxonomy at the University of Florida and the L. H. Bailey Hortorium at Cornell University, and wrote and edited gardening books at Rodale Press in Emmaus, PA. Her interests are plant identification, gardening, hiking, and reading.