7 flowers to plant in July – perennials, annuals and biennials to provide year-round blooms

Discover flowers to sow this month that can provide up to a year’s worth of color

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The garden can be a hive of color and texture in July as summer-flowering plants start to hit their peak. Perennials, biennials, and annuals can all combine in the summer to give a dazzling display of blooms to enjoy.

While it is an ideal time to sit back and appreciate the sights and sounds of a summer garden, there are some fantastic flowers to plant in July to complement that display in the months and years ahead.

It is not too late to sow flowers to bloom this winter or dazzle in future spring and summer displays. That includes a selection of beautiful perennial flowers that bloom all summer and can be sown directly into the ground this month.

A bright and colorful summer flower border

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To plant or sow flowers in July

A huge range of flowers can be purchased from garden centers, nurseries, or online to add to your backyard ideas and make an immediate impact. However, growing flowers from seed can be a satisfying and budget-friendly way to fill your garden with color and delight for years. Here are 7 great options for perennials, biennials, and annuals you may consider sowing this month.

1. Delphiniums

Blue delphinium flower spikes with yellow daisy flowers

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Delphiniums are hugely popular plants for cottage garden ideas and growing delphiniums from seed is a simple way to fill your flower beds and borders with spikes of color each summer.

Delphiniums are often sown indoors early in the year, but you can sow seeds directly outdoors in summer.

Sow the seeds into well-draining, rich soil in a sunny, sheltered position. If you miss the window to sow outdoors in July, all is not lost for the year. Delphiniums can be sowed indoors in late summer and early fall to be overwintered and planted the following spring.

2. Gaillardia

Gaillardia (Blanket flowers)

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Gaillardia are very showy perennials that can flower all summer long, filling beds and borders with bright, vivid daisy-like blooms. Also known as blanket flowers, these are native to the Americas and come in eye-popping shades of red, orange, and yellow.

Gaillardia can be simple to grow from seed. Starting them off in spring gives them time to bloom that year, however, they can also be sown in July to start flowering the following summer.

Sow seeds directly into the ground in summer, sowing thinly only a quarter-inch deep and keeping moist to guarantee germination. Hardy perennial gaillardia will grow throughout this summer and fall and then bloom from June to September in the years ahead.

3. Columbine

pink and white aquilegia

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Columbine, also known as aquilegia, is a spring flowering perennial and another favorite cottage garden plant. Sowing seeds indoors in the summer months, such as July, can give you young aquilegia to plant in the garden in fall. Alternatively, the plants can be kept in a cold frame over winter to plant in spring.

Columbine seeds will benefit from a period of cold stratification to mimic nature and encourage them to germinate quickly - this can be done by putting the seeds in a refrigerator for a couple of weeks before sowing.

Aquilegias can take two years to bloom when grown from seed, but once they start flowering they will happily self-seed around the garden so you can enjoy their bell-shaped flowers every spring into summer.

See the range of columbine seeds available at True Leaf Market

4. Sweet William

Sweet william dianthus

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Sweet Williams, or Dianthus barbatus, flower in late spring and through summer, displaying their delicate and serrated blooms in shades of red, pink, purple, and white. They can be biennials or short-lived perennials and are hardy in US hardiness zones 3-9.

Sowing seeds as late as July can produce plants that will bloom the following year. The seeds can be sown indoors or outdoors, but don’t want to be planted deep and ideally at a depth of only 1-2mm.

Starting seeds this month means you can look forward to blooms that potentially last from late spring all the way through to early fall, so head out with your pruning shears to deadhead plants throughout the summer for the longest display.

5. Pansy

Winter pansies covered in snow

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Pansies are fantastic flowers to provide color when little else is blooming in the garden. Their bright shades and color combinations can be a sight for sore eyes during the cold and dark months.

There is a wide range of winter pansies to choose from and they are very versatile, working as well along the edges of beds or borders as they do as winter plants for pots.

Sowing seeds in the first half of July gives you pansies to plant in the fall and they will flower in late winter and early spring. Sow seeds thinly on seed compost and cover with a thin layer of vermiculite.

Pot up the seedlings when they are large enough to handle and keep them moist before planting out into their final position in early fall.

Discover the range of viola seeds available at Burpee

6. Hesperis

Hesperis matronalis var. albiflora dames violet

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Hesperis, also known as sweet rocket or dame’s rocket, produces clusters of fragrant pink, purple, or white flowers in late spring and early summer.

The biennial, which also grows as a short-lived perennial, can be sowed indoors or outdoors in July. The seeds want temperatures of 60-70F to germinate and should not be covered as they need light to germinate. Starting plants indoors can protect them from extreme temperatures or storms and plants should be ready to transplant outdoors in fall.

The plants are known to self-seed widely and it is recommended to check whether it is considered invasive in your area. Removing the plants before they set seed is the best way to prevent any potential spread.

7. Strelitzia

Bird of Paradise/Crane Flower/Strelitzia reginae

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This one does not have the short-term impact of the other plants to sow on this list, but it is an unusual alternative if you want to have fun and try to grow an exciting tropical plant indoors - or to grow as an outdoor plant in a hot climate.

Strelitzia, also known as the bird of paradise, grows spectacular blooms that look like exotic birds - hence the name. The seeds are unique too, black and coated with orange hairs that need to be removed before sowing.

Propagating strelitzia from seed will be challenging, but the end reward can be worth it. The seeds want to be soaked in warm water for 48 hours and nicked with a sharp knife, before being sown into pots filled with compost. Cover the pots with a clear plastic bag to keep the environment humid.

Here comes the bad news, you need to be patient. Strelitzia seeds take up to three months to germinate, and you’ll have to wait up to five years to get that first dramatic bloom.

July can be a busy month in the garden. If you are looking for more jobs to add to your summer gardening checklist - on top of sowing flowers, of course - there are plants to prune in July and vegetables to sow that can give you harvests through to winter.

Drew Swainston
Content Editor

Drew’s passion for gardening started with growing vegetables and salad in raised beds in a small urban terrace garden. He has gone on to work as a professional gardener in historic gardens across the UK and also specialise as a kitchen gardener growing vegetables, fruit, herbs, and cut flowers. That passion for growing extends to being an allotmenteer, garden blogger, and producing how-to gardening guides for websites. Drew was shortlisted in the New Talent of the Year award at the 2023 Garden Media Guild Awards.