June gardening feels like catching the last train of the season – you’re not too late, but you better hurry! I’ve learned through years of last-minute planting that some flowers simply perform better when sown as summer begins. My garden journal is filled with notes about which seeds deliver impressive results even when I’m running behind schedule.
The magic of June-sown flowers is how quickly they transform bare patches into bursts of color. Some seeds sprout within days and flower within weeks, making them perfect for impatient gardeners like me. Nothing beats the satisfaction of watching a bare patch of soil become a flower-filled paradise in just a few short weeks.
Not all flowers are created equal for late sowing, though. I’ve had my share of disappointments – seeds that promised summer-long blooms but delivered only sparse flowers or weak plants. After much trial and error, I’ve compiled this list of tried-and-true performers (and a few notorious underachievers) to save you from wasting precious garden space.
1. Zinnia
My go-to flower when I need guaranteed color fast. Zinnias practically leap from the soil when temperatures warm up in June, often flowering within just 6-8 weeks of sowing.
Direct sowing works beautifully – just press seeds into warm soil, water consistently, and stand back. They come in every color except true blue, with varieties ranging from thumb-sized buttons to dinner-plate blooms.
Heat and drought rarely faze these Mexican natives, making them perfect for hot summer spots. For continuous blooms, I deadhead regularly and sow a second batch in early July for flowers well into fall.
2. Cosmos
Looking like delicate dancers in the breeze, cosmos deliver remarkable bang for your buck. A single packet creates dozens of plants that bloom continuously from mid-summer until frost nips them.
Their ferny foliage looks attractive even before the flowers appear, creating a soft backdrop in borders. I’ve found cosmos perform best in average to poor soil – too much fertility produces leggy plants with fewer flowers.
Butterflies flock to these simple blooms, especially the single-flowered varieties. For a meadow effect, scatter seeds in drifts rather than rows and thin seedlings to about 12 inches apart once they emerge.
3. Sunflower
From seed to towering flower in just 60-90 days, sunflowers epitomize summer gardening success. June planting gives them plenty of warm weather to reach their full potential before fall arrives.
Many gardeners don’t realize how many varieties exist beyond the classic yellow giants. I’m partial to the burgundy ‘Moulin Rouge’ and multi-branching types that produce armloads of smaller blooms for cutting.
Plant seeds an inch deep and keep the soil consistently moist until germination, which typically happens within a week. Birds love to snack on emerging seedlings, so consider covering newly planted areas with light netting until plants establish.
4. Nasturtium
Peppery-tasting edible flowers and lily pad-like leaves make nasturtiums both ornamental and practical in the summer garden. Their seeds resemble wrinkled peas and should be soaked overnight before planting for faster germination.
Unlike most flowers, nasturtiums actually bloom better in poor soil. Rich soil or too much fertilizer results in lush leaves but fewer flowers – a mistake I made in my early gardening days.
Both climbing and bush varieties grow quickly from June sowings, often flowering within 6 weeks. The ‘Alaska’ series with variegated foliage adds visual interest even when the plants aren’t blooming.
5. Marigold
Grandmother’s garden favorite remains one of the most reliable flowers for June sowing. Seeds germinate within days, and plants often begin flowering when just a few inches tall.
French marigolds stay compact and neat, while African types grow taller with pom-pom blooms. Both repel certain garden pests, making them practical companions for vegetable gardens.
Last summer, I scattered marigold seeds between tomato plants in early June and had a pest-repelling, golden display by mid-July. For strongest growth, pinch seedlings when they’re about 6 inches tall to encourage bushier plants with more flower power.
6. Morning Glory
June offers the perfect timing for these vigorous climbing vines that transform fences and trellises into floral displays. Nick the hard seed coat with a nail file and soak overnight to speed germination.
Morning glories earned their name honestly – trumpet-shaped blooms unfurl at dawn and close by afternoon. The classic ‘Heavenly Blue’ variety produces sky-colored flowers that seem to glow from within.
Growth happens almost overnight once temperatures consistently stay above 65°F. I’ve measured vines growing nearly 6 inches in a single day during warm weather! Plant where they can climb freely without overwhelming neighboring plants.
7. Portulaca (Moss Rose)
When summer heat waves threaten to fry other flowers, portulaca thrives. These succulent-leaved plants laugh at drought and poor soil while producing masses of rose-like blooms throughout summer.
Seeds are dust-like, so I mix them with fine sand before sowing to distribute more evenly. Simply press into soil surface without covering – they need light to germinate.
Flowers close on cloudy days and open with sunshine, creating a daily garden show. Modern varieties like the ‘Happy Hour’ series offer improved flower size and colors ranging from neon pink to sunset orange, all while maintaining the plant’s bulletproof nature.
8. Calendula
Often called pot marigold (though unrelated to true marigolds), calendula brings cheerful orange and yellow daisy-like flowers to the garden. June-sown seeds sprout quickly and begin flowering in about 6 weeks.
Medieval gardeners considered calendula a cure-all, and modern herbalists still value its healing properties. The edible petals add color to salads or can be dried for natural fabric dyes.
Cool weather brings out the best flower color, so these plants often take a brief break during summer’s hottest days before rebounding for a spectacular fall show. Deadhead regularly to prevent self-seeding and keep new blooms coming.
9. Bachelor’s Button (Cornflower)
Cornflower blue is such a distinctive shade that it earned its own crayon color. These hardy annuals produce button-like blooms on wiry stems perfect for cutting gardens.
June planting works especially well in regions with hot summers, as bachelor’s buttons prefer cooler temperatures. The seeds germinate rapidly – often within 5 days – and plants begin flowering about 7-8 weeks after sowing.
Beyond the classic blue, modern varieties offer pink, white, and burgundy options. I’ve found that scattering seeds directly where they’ll grow produces stronger plants than transplanting, as they dislike root disturbance.
10. Mexican Sunflower (Tithonia)
Unlike its more famous cousin, Mexican sunflower remains surprisingly underused despite its spectacular performance. The velvety orange-red flowers atop 4-6 foot plants create a tropical look from humble seeds.
Butterflies absolutely mob these plants – I’ve counted five different species visiting at once on warm afternoons. The large, slightly fuzzy leaves add textural interest even before the dramatic flowers appear.
Heat and humidity only make tithonia happier, and it laughs at drought once established. Allow plenty of space when planting, as these grow into substantial shrub-like plants that can shade out smaller neighbors.
11. Four O’Clocks
Named for their habit of opening in late afternoon, four o’clocks bring fragrance and color to the garden just when other flowers are closing for the day. Their trumpet-shaped blooms emit a sweet perfume that intensifies at dusk.
Large, black seeds are easy to handle and sprout reliably within 7-10 days of planting. By mid-summer, bushy plants reach 2-3 feet tall and wide, covered with flowers in magenta, yellow, white, or marbled combinations.
Hummingbirds and sphinx moths (which look like tiny hummingbirds) visit the nectar-rich blooms in evening hours. Plants form tuberous roots that can be dug and stored in milder climates for replanting next year.
12. Celosia
With flower forms resembling either plumed feathers or corrugated brain coral, celosia brings architectural interest to summer gardens. June-sown seeds develop quickly in warm soil, often flowering within 8 weeks.
The ‘Dragon’s Breath’ variety turned my garden into a conversation piece last year with its fiery red plumes that seemed to glow from within. Celosias maintain their color even as they dry, making them excellent for cutting and winter arrangements.
These heat lovers actually perform better during summer’s dog days than in spring’s cool temperatures. Avoid overwatering, as they’re prone to root rot in soggy conditions – a mistake that cost me several plants one rainy season.
13. Dwarf Sunflowers
Perfect for containers or front-of-border planting, dwarf sunflower varieties pack all the cheerful charm of their taller relatives into compact 12-24 inch plants. June sowing ensures they’ll bloom during summer’s peak.
Varieties like ‘Teddy Bear’ produce fully double, fluffy blooms that resemble chrysanthemums rather than typical sunflowers. Others, like ‘Suntastic Yellow’, begin flowering when barely a foot tall and continue for weeks.
Unlike their skyscraper cousins, these shorter types rarely need staking and produce multiple blooms per plant. Children especially delight in growing these kid-sized sunflowers that develop from recognizable seeds to flowers in just 50-60 days.
14. Sweet Alyssum
Creating a honey-scented carpet of tiny blooms, sweet alyssum grows from nearly invisible seeds to flowering plants in just 6-8 weeks. June-sown alyssum provides continuous color through fall, especially if sheared back midsummer.
The low-growing habit (just 4-6 inches tall) makes it perfect for edging beds or filling spaces between larger plants. White varieties like ‘Snow Princess’ seem to glow in evening light, creating a magical effect along garden paths.
Beneficial insects love the nectar-rich blooms, making alyssum a practical addition to vegetable gardens. Modern heat-tolerant varieties like the ‘Clear Crystal’ series perform better in summer than older types that tended to fade in high temperatures.
15. Salvia
Annual salvias bring vertical interest and pollinator appeal to summer gardens. The upright flower spikes in shades of red, blue, or white create architectural elements among more mounded plants.
June sowing works particularly well for varieties like ‘Victoria Blue’ and ‘Red Hot Sally,’ which develop quickly in warm soil. Most begin flowering when plants are just 8-10 inches tall and continue non-stop until frost.
Hummingbirds zoom straight to these nectar-rich blooms, often returning multiple times daily. Most salvias perform beautifully during summer’s hottest days and require minimal care beyond occasional deadheading to look their best.
16. Cleome (Spider Flower)
Dramatic and slightly otherworldly, cleome produces softball-sized flower clusters atop tall stems that sway gracefully in summer breezes. June-sown seeds develop into impressive 3-4 foot plants by August.
Each bloom cluster resembles an exploding firework, with long stamens protruding like spider legs (hence the common name). The unusual flowers in white, pink, or lavender attract both butterflies and admiring glances from garden visitors.
Small thorns along the stems can surprise unwary gardeners, so place these where they won’t be brushed against frequently. Self-seeding occurs readily, but unwanted seedlings pull easily in spring – I leave a few volunteers each year for free plants.
17. Gomphrena (Globe Amaranth)
Resembling lollipops on stems, the perfectly round flower heads of gomphrena bring whimsical charm to summer gardens. Their papery texture maintains color even during heatwaves that would wilt other blooms.
June planting works perfectly for these heat-lovers that prefer warm soil for germination. Once established, they’re remarkably drought-tolerant and bloom continuously without deadheading.
The clover-like blooms in magenta, orange, white, or purple last nearly forever in dried arrangements. I’ve had vases of cut gomphrena maintain their color for over a year indoors! For best results, space plants about 12 inches apart to allow good air circulation.
18. Impatiens (Traditional Varieties)
Despite their popularity as shade-garden staples, traditional impatiens consistently disappoint when started from June-sown seeds. They simply grow too slowly to provide meaningful summer color when started this late.
Downy mildew disease has devastated these plants in recent years, making them an increasingly risky choice regardless of timing. Seeds are dust-like and challenging to handle, with germination often spotty at best.
I’ve tried starting them in June three different years with the same lackluster results – tiny plants that barely begin flowering before fall arrives. If you must have impatiens, purchase started plants rather than attempting late-season seed sowing.
19. Geranium (Pelargonium)
The classic geraniums seen in window boxes throughout Europe seem like they’d be easy from seed, but June sowings invariably lead to frustration. From seed to flower takes 12-16 weeks – far too long for late-season starting.
Germination itself proves challenging, with seeds requiring specific temperature conditions and often sprouting unevenly. Even when successful, seedlings grow painfully slowly compared to other summer annuals.
After multiple disappointing attempts, I’ve accepted that geraniums are best purchased as started plants or grown from cuttings. My June-sown seeds produced plants that were just hitting their stride when frost arrived – hardly worth the effort and garden space.
20. Petunias
Despite their ubiquity in garden centers, petunias from seed represent one of gardening’s greatest disappointments for June sowing. The dust-like seeds germinate erratically and require professional-level care to develop properly.
Growth happens at a snail’s pace even under ideal conditions. My June-sown petunias produced spindly plants with few flowers well into August, while store-bought plants nearby flourished with blooms.
Modern hybrid varieties (which perform best in gardens) don’t grow true from collected seeds, adding another layer of potential disappointment. Save yourself the frustration and purchase started plants instead – they’re widely available and reasonably priced for the performance they deliver.