5 super-fast flowers to sow in May to get your garden blooming quickly — these will bring instant color to your yard

Zinnias in a selection of colors
(Image credit: Shutterstock)

I’m an impatient gardener, and I often get frustrated waiting for seeds to come into flower, but this month I’ll be sowing some quick-starters to enjoy almost instant color.

Apart from satisfying my eagerness to see a garden full of bright hues, these quick bloomers will help fill in my beds, borders and containers while I wait for other plants to come to life.

Rather than spending money on already-established nursery plants, these quick bloomers are perfect to grow from seed, and are one sure way to save money in the garden. What’s more, right now in May, with the soil starting to warm, it's the ideal time to direct sow outdoors, making these flowers both budget-friendly and easy to grow.

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Here I share my favorite five flowers I’ll be sowing in my own backyard this month.

1. Cosmos

Cosmos flowers in a field

(Image credit: Shutterstock)

Cosmos are beautiful, delicate flowers. But apart from their golden centers and delicate petals, I love their airy foliage. What’s more, whether you prefer pastels or bold colors, there’s a cosmos to suit every taste.

In warmer soil, cosmos seeds can be planted directly outside, just scatter them over the ground and cover with ¼ inch of soil before raking over. They will germinate quickly without much care and will do particularly well in poor soil. But avoid over-fertilizing these flowers, as you could end up with tall, leafy plants with few blooms.

You’ll have to wait between 7 and 10 weeks for the flowers to appear after sowing.

Best for USDA zones: 2-11

2. Nasturiums

Red, orange and yellow nasturtiums in flower

(Image credit: Shutterstock)

Just like cosmos, nasturtiums are pretty much fuss-free and easy to grow in poor soil. I prefer nasturtiums with bright orange blooms, and love the punch of color they add to my flower beds and containers. However, they also come in yellows and reds and trailing varieties, which make them perfect for hanging baskets.

Apart from being quick growers, nasturtiums are also edible plants and make a perfect addition to a vegetable garden, as they can repel pests such as cabbage loopers, aphids, whiteflies, squash bugs and some beetles.

You’ll have to wait 4 to 8 weeks after sowing for the flowers to appear.

Best for USDA zones: 2-8

3. Zinnias

Zinnias in bloom

(Image credit: Shutterstock)

If you’re looking for a flower to add impact to your garden, the zingy Zinnia is your best bet. The beautiful, compact petals are a sight to behold and a magnet for bees and butterflies.

Seeds can be sown outdoors when the last chance of frost has passed, and the soil is warm. They become unhappy when their roots are disturbed, so direct planting is preferred over starting the seeds indoors.

Once planted, they will take 8 to 10 weeks to bloom.

Best for USDA zones: 2-11

4. Cornflowers

Multi-colored cornflowers in bloom

(Image credit: Shutterstock)

May is the ideal time to sow cornflowers that will present you with pretty ruffled blue flowers in time for summer. Cornflowers can be planted in drifts or in clumps to act as space fillers.

Sow the seeds directly into the ground or a pot and rake over with a light covering of soil. They are easy to grow, and once sown, can be left alone, making them a fun project for children or novice gardeners.

Cornflowers are ideal to sow in May and will give you flowers in 10 weeks, in time for summer.

Best for USDA zones: 2-11

5. Sunflowers

Dwarf sunflowers

(Image credit: Shutterstock)

Another favorite among young gardeners is the sunflower, which is guaranteed to add height, structure and color to any garden. Sunflower seeds should be planted in a sunny spot that is sheltered from the wind. If not, be prepared to stake your plants to avoid them tumbling over, or choose a shorter variety.

Plant your seeds 1 to 2 inches deep in warm soil, spacing smaller varieties 6 inches apart, and larger varieties 12 inches apart. Sunflowers appreciate an occasional watering and a feed.

The time it takes sunflowers to flower will depend on the variety, but for a quick starter, opt for dwarf varieties that can bloom within 50-60 days.

Best for USDA zones: 3-10

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Camilla Sharman
Staff Writer, Homes

Camilla is the Homes Staff Writer and covers everything to do with homes and gardens. She has a wealth of editorial experience, mounting over 30 years, and covers news and features, tests products for reviews and compiles buying guides. 


Her work has appeared in business and consumer titles, including Ideal Home, Real Homes, House Beautiful, Homebuilding & Renovation, and Kitchen & Bathroom Business. She’s even appeared on the cover of Your Home, writing about her own house renovation.


Although she’s obsessed with decorating her home, she also enjoys baking and trying out the latest kitchen appliances. But when she’s not inside, you’ll find her pottering about in her yard, tending to her vegetable patch or taking in her prized hydrangeas.

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