9 Must-Sow Flower Seeds For June That Bloom Fast And Keep Your Garden Bursting With Color All Summer Long

Summer is all about flowers, but if you didn’t start them earlier in spring, not to worry. June is far from too late to enjoy garden blooms, even those started from seed. In fact, this is a great time to start flowers for midsummer and late summer or even fall flowers. As your spring blooms begin to fade, start seeding these faster-growing flowers for additional color to come.

Because the warm weather is already here, there’s no need to start seeds indoors. Sow your summer flower seeds directly outdoors, either in beds or containers. The best flowers to plant in June are fast-growing annuals, but certain perennials are perfect too.

Before planting seeds, prepare the soil by digging and turning it, adding compost or fertilizer, and making any necessary amendments to improve drainage. Sow the seeds to the planting depth and with the flower spacing listed on the seed packet. You will need to plant more seeds than you intend to grow. As they germinate and sprout, thin the seedlings, keeping only the healthiest and strongest growers.

While the seeds are germinating and sprouting, keep the soil consistently moist. This is especially important in summer when the weather may get hot and dry. Keep watering seedlings as they grow.

Get busy planting with these stunning flowers to start from seed in June. You can find many of our top picks, plus seed-starting essentials and growing kits, in the Gardening Know How Shop.

1. Zinnias

Zinnias are staples of the summer cutting garden. These pretty, brightly colored flowers are good for procrastinators, too. They love the heat of summer and will germinate in as little as five days if soil temperatures are at least 70°F (21°C).

In just eight weeks of hot summer weather, your zinnias will bloom and keep flowering well into fall. Deadhead the spent flowers to encourage more. As a bonus to enjoying cut flowers and a profusion of garden color, zinnias attract butterflies.

Try our Zinnias for Cutting Collection, which includes five captivating varieties, all with dahlia-style blooms.

2. Marigolds

This cheerful annual is another classic element of the summer garden. Marigolds thrive in full sun and are great companions for the vegetable garden. Their strong scent deters many pests, so use them around the veggie bed, even as a border. French marigolds are best for this purpose, and are also some of the most beautiful, such as Tiger Eye marigolds, available in the Shop.

Sow seeds for marigolds in June and expect to get flowers in about eight weeks. They should bloom all summer and into the fall, right up to the first frost. Deadhead the flowers continuously to encourage additional blooms.

3. Bachelor Button

Also known as cornflower, bachelor button is an annual that loves a spot with full sun. The plants are very easy to grow from seed and will develop quickly and readily, rewarding you with beautiful blue blooms.

In warmer climates, they can become weedy, but where they are annual, they enjoy their easy growth in summer. Your bachelor’s buttons will germinate in a week or two and bloom in less than 10 weeks.

4. Four O’clocks

These striking, trumpet-shaped flowers are named for the fact that they open in the afternoon and evening. Four o'clocks attract pollinators, including evening moths. A perennial in zones 9 or 10, in colder climates, you can sow seeds now and enjoy blooms on your four o’clocks for late summer and well into fall.

Sow the seeds in rich soil that drains well and in full sun for the best results. Soak the seeds overnight before sowing to speed up germination, which should take about a week.

5. California Poppy

This sunny, bright orange poppy is the state flower of California. It’s a perennial in zones 8 through 11, but a fast-growing summer annual elsewhere. Sow California poppy seeds now, and they will germinate in a couple of weeks and bloom in 8 to 10 weeks. They love sunlight and prefer rich soil, but will also tolerate poor, dry soil. They don’t need much water either, so they make a great choice for hot, dry summers.

6. Cosmos

Cosmos go from seed to flowers in as little as eight weeks. However, they might take a little longer, so be patient. Also known as Mexican aster, cosmos thrive in hot, dry conditions, making them a perfect summer annual. They’ll also attract pollinators and birds to your garden.

There are many varieties of this daisy-like beauty to choose from, but these Cupcakes and Saucer cosmos, available in the Shop, are unlike anything else with their unique bowl-shaped appearance.

7. Sunflower

Don’t forget this classic annual for fall. Sow seeds in June and you’ll be growing sunflowers in about ten weeks, just in time for late summer and fall color. Varieties include the giants most people associate with sunflowers – such as Gigantus, available in the Shop – to those with petite faces, like these Italian white sunflowers.

Sunflowers prefer full sun and rich, well-drained soil. If you’re planting any of the giant varieties, keep in mind that they might need some support as they become top-heavy later.

8. Coneflower

Many perennials will not bloom in the first year, but there are a few you can try and expect good results. Sow coneflower seeds in June, and you stand a chance of getting flowers this fall from these fast growers. They bloom prolifically once they get going and, if deadheaded, will flower well into fall and up to the first frost.

While usually seen in purple, they actually come in shades of yellow, pink, orange, white, and red – our Cheyenne Spirit coneflower mix contains a dazzling array of hues.

Coneflowers are native and support pollinators. Leave the seed heads in place in fall to feed birds.

9. Coreopsis

This is another perennial worth seeding now. They grow very quickly from seed and can bloom in as little as 60 days. Coreopsis – or tickseed – is a member of the aster family and produces a profusion of small, daisy-like yellow flowers. Once your coreopsis blooms and the flowers start to fade, cut them back to encourage a second flush of late fall flowers.

This article features products available from third party vendors on the Gardening Know How Shop.