15 Fast-Growing Annuals to Start From Seed

As soon as the winter weather dissipates, we gardeners set about our work to revive the garden and bring it back to its full blooming glory. Naturally, we want to see things booming and blooming as soon as possible, but as Audrey Hepburn once said, ‘To plant a garden is to dream of tomorrow.” 

But why put off until tomorrow what you can enjoy today? While you’re waiting for the pretty perennial plants in your garden to replenish their stores and return to their former grandeur, there are plenty of fast-growing annual flowering plants that can grow and bloom quickly from seed, filling in the spaces left by winter’s icy extinction. 

By planting these expeditious annuals, you can regain your garden’s lush abundance in short order. Here are 15 of our favorite fast-growing annuals to get your garden flourishing and thriving again in no time. 

Seeds Featured In This Article

Rubenza Cosmos

	botanical name Cosmos bipinnatus ‘Rubenza’
	sun requirements Full Sun
	height 24”-32”

Cosmos are terrific little plants that produce a ton of flowers and require very little effort from the grower. ‘Rubenza’ has bold red blooms that look gorgeous in the garden or a vase, as they make excellent cut flowers. 

As the blooms age, the color fades to a wonderful terracotta color. The fading effect of the flowers means that one plant can have many different intensities of the same color at the same time. The foliage is soft and fernlike, adding a delicate textural element to the flowerbed. 

Plant these annual seeds in full sun in the spring and watch them take off fast. These plants flower from summer until frost, and pollinators absolutely adore them. The movement of the flowers as they sway beneath the weight of local bees and butterflies is magical. 

Black Magic Bachelor’s Button

	botanical name Centaurea cyanus ‘Black Magic’
	sun requirements Full sun
	height 20”-24”

Bachelor’s Button readily self-sows, so while it is an annual, once you plant the seeds, you’re very likely to see it return every year. The most common color for these flowers is cornflower blue, but ‘Black Magic’ is a personal favorite and a must-have if you like the dark and moody goth garden look. 

Direct sow these seeds in fall in milder climates and in spring in cool climates for blooms that begin showing off in early summer and continue until the first frost. They are drought-tolerant and pollinator-friendly, and the seed heads are a great food source for birds in the fall. 

‘Shades of Blue’ Larkspur

	botanical name Consolida regalis ‘Shades of Blue’
	sun requirements Full sun
	height 3’-4’

Larkspurs produce wonderfully tall and stately flowers that make a wonderful addition to the cottage garden or any colorful flower bed. ‘Shades of Blue’ is a gorgeous variety that mingles light, dark, and medium blue larkspur seeds together for an incredible display of cool color. 

Direct sow these annual seeds in the early spring, as soon as the ground can be worked, because they prefer cool weather. They bloom from late spring into the summer in warmer climates and can bloom into the fall in cooler climates. 

Not to be mistaken for delphinium, which is a perennial, larkspur has a very similar appearance, and like delphinium, all parts of the plant are highly toxic when ingested. This is not a great plant for owners of pets who like to snack on plants. Otherwise, it is stunning in the garden and as a cut flower. Just make sure to wear gloves!

‘Zeolights’ Calendula

	botanical name Calendula officinalis ‘Zeolights’
	sun requirements Full sun
	height 12”-24”

Calendula is one of those flowers that have a great number of uses, both practical and ornamental. Often used as a medicinal preparation for treating cuts and abrasions, calendula flowers are also edible and have a nice flavor. They are great for decorating baked goods and salads. They also happen to be quite beautiful and fast-growing.

‘Zeolights’ is an exciting variety of Calendula that has showy pale yellow flowers with bronze and pink accents. The back of the petals are maroon, creating an exquisitely multi-dimensional appearance. 

Taking fewer than two months from sowing to bloom, you can plant these flowers in spring and fall for many seasons of interest. They are frost tolerant, so they do very well in colder climates, with flowers and foliage lasting into the winter.

‘Queeny Lime Orange’ Zinnias

	botanical name Zinnia elegans ‘Queeny Lime Orange’
	sun requirements Full sun
	height 30”-40”

I’m a huge fan of zinnias. I can’t think of another annual flower that is as easy to grow from seed and as big a bloomer with so little care. Zinnias bloom in as little as 40, with an average of 60 days from planting to blooming, and you can plant them as soon as the ground thaws until late summer to have these wonderful flowers blooming in your garden for three seasons. 

‘Queeny Lime Orange’ is a very popular and award-winning variety, and it’s not hard to see why. Large, flamboyant flowers are lime green in the center, fading to a rich orange at the outer petals. With long stems and long-lasting flowers, these make excellent cut flowers. 

Direct sow your zinnia seeds whenever you like, in direct sun. They aren’t picky about soil, but fertilizer boosts growth and gives you the most spectacular floral show. These are drought-tolerant and continue to bloom through the hottest months of summer.

‘My Navy’ Sweet Pea

	botanical name Lathyrus odoratus ‘My Navy’
	sun requirements Full sun to partial shade
	height 8’

Sweet peas are special plants that not only bloom quickly from seed, but also replenish the nitrogen levels in your soil for next year’s plants. ‘My Navy’ is a striking and fast-growing variety with large, fragrant, deep blue flowers on long stems, making them excellent for cutting. 

As vining plants, sweet peas need something to climb on, and they look gorgeous on a trellis or arbor in the garden. These are great producers that bloom from late spring through the summer in mild climates. Very hot weather can make them turn a bit shy. 

Direct sow these annual seeds in a spot where the vines will get morning sun and afternoon shade. This combination keeps them blooming as the weather heats up. Protection from the hot afternoon sun makes these plants happiest. Their preferred soil conditions are rich, loamy, and moist, but well-draining. 

‘Black Velvet’ Nasturtium

	botanical name Tropaeolum minus ‘Black Velvet’
	sun requirements Full sun to partial shade
	height 10”-12”

With lilypad-like leaves and bright, cheerful, and edible flowers, what’s not to love about nasturtiums? ‘Black Velvet’ is a wonderful variety with deep, oxblood-colored flowers contrasted with bright green, heavily veined leaves. 

Nasturtiums grow best with some protection from the afternoon sun, but the morning sun will make your leaves and flowers perky and plentiful. They are not technically considered frost-tolerant, but they do surprisingly well in cooler temperatures. You can sow these annual seeds in early spring or late summer for blooms that show up in as little as one month but closer to 45 days on average. 

‘Night and Day’ Snapdragon

	botanical name Antirrhinum majus ‘Night and Day’
	sun requirements Full sun to partial shade
	height 18”

Snapdragons are a childhood favorite for so many gardeners. For myself, their bubbly, beautiful blooms never quite lived up to the fierceness of their name, but what a distinctive name it is. Although they are technically perennials in the right climate, they are usually grown as cool-weather annuals.

‘Night and Day’ is an edgy variety with bold red and white flowers. The red portions of the flowers and foliage deepen to nearly black when the weather cools off in the fall, but the lower portion of the blooms remain white, creating a striking contrast. 

Plant these in early spring for late spring and early summer blooms. Your snapdragons may look tired and slow down in the heat of summer but don’t pull them yet. In the fall, they will come back and bloom again. Placing them in a space that has shade in the afternoon keeps them looking healthy in the warmer months.

‘Black Swan’ Poppy

	botanical name Papaver somniferum ‘Black Swan’
	sun requirements Full sun to partial shade
	height 24”-36”

If you are planning a cutting garden this year, don’t overlook ‘Black Swan’ Poppies as the most exquisite addition. Poppies are wonderful flowers that look amazing in the garden and, arguably, even better in a floral arrangement. Black Swan has amazing, semi-double flowers with finely cut petals that have a fringelike appearance. 

Poppies don’t like to have their roots disturbed, so direct sowing is a must. These annual seeds need a period of cold, so direct sow in late fall for early spring germination. They can be sown in spring for summer blooms as well, but the seeds need artificial cold stratification in this case. 

‘Miss Jekyll Blend’ Love-In-A-Mist

	botanical name Nigella damascena
	sun requirements Full sun
	height 12”-24”

Love-in-a-Mist will add an airy and ethereal feeling to your garden and to bouquets, as this flower works well both as a cut flower and in dried flower arrangements. ‘Miss Jekyll Blend’, named after famed garden designer Gertrude Jekyll, blooms in shades of cool blues. 

Direct sow these seeds in spring, as they don’t like to be disturbed, so transplanting is not always successful. Even though they are annuals, Love-in-a-mist self-sows readily. Sow seeds every two weeks until midsummer for continuous blooms through the fall. 

Scarlet Flax

	botanical name Linum grandiflorum ‘Scarlet’
	sun requirements Full sun to partial shade
	height 12”-24”

Flax flowers are ephemeral, lasting for only one day, but they bloom so profusely that they bring a great amount of color to the garden. Scarlet Flax brightens your beds with tons of brilliant color from these lovely little flowers. 

These fast bloomers are a hit with butterflies, and they tolerate the heat of summer very well. Drought-tolerant and heat-tolerant, they begin blooming within six months of sowing and continue until the first frost.

Plant them in full sun for the best blooms, but they tolerate and will still look great in partial shade. These can be started early indoors, four to six weeks before your last expected frost date, and transplanted for early spring blooms. 

‘Ruby Moon’ Hyacinth Bean

	botanical name Lablab purpureus ‘Ruby Moon’
	sun requirements Full sun to partial shade
	height 10’-20’

This is a personal favorite for me, as I adore a flowering vine, and this vine shows up strong. A rapid grower, ‘Ruby Moon’ has gorgeous purple vines and a purple tint to the foliage as well. The flowers bloom on long stems, making them great for cutting and adding a vertical element to floral arrangements. 

The blooms are a rich shade of purple and have a wonderful fragrance. In most respects, these are very similar to sweet peas. Pollinators adore this plant for its abundance of blooms. Bees are particularly attracted to it because purple and blue are a bee’s favorite colors. Pollinated flowers form attractive, shiny, purple pea-shaped pods. 

The pods can re-seed quite aggressively and can be left to form a stunning ground cover. They are easily pulled up when the sprouts are young, though, so it’s not difficult to contain as long as you are vigilant about pulling them in the following spring. ‘Ruby Moon’ transplants very well and requires very little care. It can grow in full sun or partial shade, with morning sun and afternoon shade producing the best flowering. 

‘White Lace’ Orlaya

	botanical name Orlaya grandiflora ‘White Lace’
	sun requirements Full sun to partial shade
	height 18”-30”

Orlaya produces wonderfully delicate, lacy-looking flowers on long, strong stems, making it great for the cutting garden. It has a bushy habit and blooms for an extended period, so it brings a lot to the flower bed. ‘White Lace’ is reminiscent of Queen Anne’s Lace, another lovely flowering plant, but the flowers are surrounded by larger petals toward the outer edges. 

Start your annual orlaya seeds indoors four to six weeks ahead of the last frost in cooler climates. In warmer climates, they can be sown in late fall for early spring germination. After your first planting, sow seeds every two weeks for an extra-long blooming season. Full sun to partial shade is fine for these flowers. 

‘Cambridge Blue’ Lobelia

	botanical name Lobelia erinus
	sun requirements Full Sun to part shade
	height 6′

While it isn’t the fastest bloomer on the list, lobelia produces an amazing profusion of flowers from late spring through the fall. Sow ‘Cambridge Blue’ indoors up to two months ahead of your last frost, and you’ll have masses of gorgeous periwinkle flowers in early spring that begin blooming after another month and fill your garden with color. 

In warmer climates, your lobelia may even continue to bloom through the winter and is known to self-seed under the right conditions. Pollinators are very attracted to the abundance of flowers, and this plant makes an excellent container plant as it has a trailing habit and will overhang the sides of a hanging basket or potted arrangement. 

Bluebonnet

	botanical name Lupinus texensis
	sun requirements Full sun
	height 12”-24”

If you want to attract pollinators to your flower garden, bluebonnets do the trick. This butterfly host plant is a larval food for several types of butterflies, including the Gray Hairstreak, Orange Sulphur, and Painted Lady. It hails from Texas, where it can be found growing in gorgeous drifts along roadsides and in meadows. 

Best when directly sown in the garden, plant these seeds in the fall for early spring germination. The roots don’t like to be disturbed, so be very careful if starting indoors and transplanting. It is best to use pots that biodegrade if doing so. This species of lupine has stunning panicles of blue flowers with white tips that are fragrant as well. 

Final Thoughts

Perennials are the backbone of a flourishing garden, but annuals bring the flowers in a major way. Get your garden started back on its way to being a blooming, burgeoning paradise quickly this spring by planting some of these wonderful, fast-growing annuals.