Top 10 Fast-Growing Annuals From Seed

Get a jump-start on spring planting with the prettiest and fastest-growing annuals around.

Annuals are a surefire way to quickly add a pop of color to containers, window boxes and bare spots in flower beds. But you get the best bang for your buck and a promise that they’ll sprout in a hurry when you start spring annuals from seed. Sow these hardy, fast-growing annuals directly in the ground in early spring, and before you can say “summer,” your backyard bursts into bloom. (Read more: 13 Ways to Take Your Garden from Good to Great)

3 Types of Annuals and When to Sow Them

Hardy: If your soil is workable, the seeds can go right in the ground.Or start indoors eight to 10 weeks before last frost date and transplant about a month later. (Psst! Many of the annuals in our list are hardy annuals!)

Half-hardy: Sow outdoors after threat of hard frost (below 25 degrees Fahrenheit) has ended. Or start indoors six to eight weeks before last frost date.

Tender: Place seeds in the ground after all danger of frost has passed. Or start indoors four to six weeks before last frost date.

(Read more: Top 10 Sunflower Varieties to Grow)

photo credit: WerbeFabrik/pixabay

1. Marigold

Tagetes

You can bet on this bang-for-your-buck classic, with bright blossoms of yellow, orange and mahogany that show themselves within eight weeks of sowing. For best results, plant marigold in full sun and in well-draining soil. Interestingly enough, these blooms flourish in poorer soils, so no fertilizer is necessary.

Why we love it: With a no-wilt demeanor, it makes the perfect garden addition. Plus, deer steer clear of it.

photo credit: Tingeling/pixabay

2. Sweet pea

Lathyrus odoratus

This vining vixen, with ruffled blossoms and slender tendrils, looks best when climbing—on bean tepees, arbors, trellises or fences. Sweet peas like it cool, so gardeners in northern climates should sow in early spring, while southern dwellers are wise to plant in fall. Soak seeds for several days before planting.

Why we love it: The intoxicating fragrance—a mix of honey, jasmine and orange—perfumes the air with a seductive scent that sends you swooning.

photo credit: skeeze/Pixabay

3. Morning glory

Ipomoea

Old-fashioned charm and trumpet-shaped flowers in pink, white, purple, blue and magenta make this quick-growing vine a favorite. A true sun worshipper, the petals unfurl every morning to greet the day. File or chip the outer coat of the seed with a sharp knife or razor blade and soak in warm water for a day or two before planting for best germination results.

Why we love it: The foliage—heart-shaped, bright green leaves among curlicue tendrils—is as lovely and romantic as the blooms themselves. 

photo credit: Efraimstochter/pixabay

4. Zinnia

Zinnia elegans

These perky bloomers are available in almost every color imaginable. Tiny seedlings show up in mere days after sowing, with flowers appearing about six weeks later. Bonus: Zinnias are bouquet favorites.

Why we love it: Flowers don’t get much more low-maintenance than zinnias. They need almost zero care during the growing season. Just make sure you select disease-resistant varieties to avoid powdery mildew

photo credit: Rose Reising (B&B reader)

5. Phlox

Phlox drummondii

A vigorous grower that’s as pretty as it is tough, phlox is a smart choice for gardeners looking for a quick fix in a hard-to-grow spot. Tiny bunches of dainty flowers in hues of pink, red, white, blue and purple create drifts of color, particularly in early summer, that look impressive along borders and in containers.

Why we love it: Its cottage-garden charm is worth the minimal effort it takes to grow. Bees, butterflies and birds thank you, too

photo credit: Anteromite/Shutterstock

6. Bachelor’s button

Centaurea cyanus

Cute as a button, its frilly flowers are a throwback to Grandma’s garden. Easy to grow and fast to show, they should be sown in sunny areas where the mature plant can self-seed and naturalize. Butterflies and other pollinators can’t get enough of this perfect addition to cutting and cottage gardens.

Why we love it: Not many flowers out there naturally boast a true blue hue. Plus, it looks just as pretty cut and dried as it does fresh.

photo credit: Pezibear/Pixabay

7. Nasturtium

Tropaeolum majus

Technically an herbaceous perennial, nasturtium is often treated as an annual. Fast-growing and easy to care for, it wins the prize for prettiest edible flower, with brilliant orange blooms on top of emerald green foliage. Seedlings appear in a little over a week after sowing. If a softer hue is more your style, try creamy yellow Peach Melba.

Why we love it: The peppery blooms and leaves are delicious in salads when you go pesticide-free. Grow just outside your kitchen in a container garden or as a ground cover within arm’s reach of your front door.

photo credit: sumikophoto/Shutterstock

8. California poppy

Eschscholzia californica

With fernlike foliage, cupped blooms the color of the setting sun, and an easy-growing nature, there’s a lot to like about this native-to-some-states wildflower. As its name suggests, it thrives in full sun. Don’t expect much of a show when it’s overcast or raining, though, because its flowers close in protest.

Why we love it: A reliable display brings dazzle to dry spots in the garden. Use poppies when xeriscaping, in a rock garden or in that spot in the yard that’s hard to reach with the hose.

Bonus Tip! California poppies bloom more prolifically with the help of a little deadheading. Leave a few spent flowers on the stems, though, because the plant self-seeds.

photo credit: Deborah Welch (B&B reader)

9. Sunflower

Helianthus annuus

Loved by artists, gardeners and wildlife alike, this daisy-shaped beauty with showy blooms and vintage charm grows 6 feet or more in just three months. Plant in flower beds and cutting gardens, or along borders. Remarkably tough sunflowers love long, hot summers and thrive in full sun with moist but well-draining soil.

Why we love it: Red, yellow, white or bicolor, there’s a sunflower to fit any style. Strawberry Blonde and Moulin Rouge cultivars are must-haves.

photo credit: Karen Harris (B&B reader)

10. Cosmos

Cosmos bipinnatus

Truly out of this world, cosmos’s elegant, crepelike blooms on long, slender stems are like no other. While seeds get off to a super fast start, the plant’s blooms are at their best in summer, so patience is key. Care is minimal and the show is spectacular. Just be sure to protect cosmos from strong winds.

Why we love it: This plant self-seeds and spreads with ease. Frugal gardeners may want to harvest seeds in fall to replant in different locations in spring

Rachael Liska
Rachael Liska is a freelance writer and editor specializing in birding, gardening, food and family.