7 Perennials to Plant in May for Jaw-Dropping Color That Starts in Spring and Lasts All the Way Through Summer

Who doesn’t love the month of May? Here in France, May 1st is even a national holiday. Writer Emily Brontë called May “the month of expectation, the month of wishes, the month of hope." I think that covers the month perfectly.

To us gardeners, expectation, wishes, and hope in spring all center around plants in the landscape. All flowering plants bring joy, but perennials are especially sweet since you plant them once and enjoy them year after year.

A friend likes to remind me that the best perennial is the one blooming at the moment, but each plant has an ideal planting month. The merry month of May is without question the best planting time for a number of my favorite perennials. That’s because by late spring, the weather is warmed, the soil is moist, and I’m ready to get my hands dirty – and you probably are, too! Here are the best perennials to plant this month.

Best Perennials to Plant in May

There are so many stunning perennials to choose from and so many that are perfect for planting in May. But these outstanding varieties are the ones that are at the top of my May must-plant list this year.

1. Garden Phlox

The flowers of garden phlox (Phlox paniculata) are eye-poppingly colorful with a strong, sweet fragrance. It’s a wildflower in the eastern and central United States and is hardy in USDA growing zones 4-8. The showy blossoms appear in summer and bloom through fall in shades of lavender, lilac, pink, purple, salmon and white.

Plant garden phlox in a spot with some sun, whether full or partial. It also needs well-draining, moist soil, so work in some organic compost before planting time.

This shrub is also called tall phlox and here’s the reason: it can grow to 4 feet (1.3 m) high! It spreads, too, up to 3 feet (1 m) wide. The big blooms attract butterflies and hummingbirds, but also make great cut flowers.

Shop stunning garden phlox and creeping phlox plants from Nature Hills Nursery.

2. Catmint

Catmint (Nepeta spp.) is part of the large mint family, so it has quick-growing foliage that’s topped with spikes of delicate purple flowers.

I adore the classic lavender blossoms on these ornamental herbs, but the pink and white cultivars are pretty, too. The blooms attract pollinators while the foliage repels mosquitoes and other unwanted insects.

Catmint thrives in USDA hardiness zones 4-8. It flowers in early summer and keeps right on going through fall. The plants get up to 2 feet (0.6 m) tall and wide.

Get high-quality 'Cat's Pajamas' catmint plants online from Wayside Gardens.

3. Bleeding Heart

If there’s one perennial straight out of a Disney movie, it’s the bleeding heart (Dicentra spectabilis). Cute is not strong enough a term to describe the deliciousness of the string of puffy, heart-shaped pink blossoms each with a little white, protruding “tongue” and a red streak down the middle. And here’s more good news: this flower prefers a shady location.

Bleeding heart is native to Asia but thrives in zones 3-9. Its long, arching stems can grow up to 3 feet (1 m) tall. Each one typically grows around 20 of the heart-shaped flowers in spring. The adorably romantic flowers last for two or three weeks and return again year after year. Take care around children and pets since bleeding heart plants are very toxic.

Shop pretty pink or elegant white bleeding heart plants from the Home Depot.

4. Columbine

Plant columbine (Aquilegia spp.) seedlings or starts in May after all danger of frost has passed. It’s another of my very favorites, although the blossoms don’t last for more than a few happy weeks. My loyalty stems from the cuteness of the flowers, which look very much like a colorful jester’s cap.

Plant columbine in a full sun location if you live in a cool climate or a part-shade location in warmer locales. It thrives in USDA hardiness zones 3-8. It’s not a perennial that loves the heat and it wilts in hot summer weather. Columbine is also toxic to humans and pets.

Columbine is easy to start from seeds or transplants. You can get both from Burpee.

5. Shasta Daisy

The Shasta daisy (Leucanthemum x superbum) is not a fancy flower, but it’s cheerful, cute, and drought tolerant. This perennial flower has the classic daisy look: a sun of slender white petals surrounding an egg-yolk yellow center. The leaves present a pleasant contrast in a rich, dark green.

Shasta daisy stems can grow up to 3 feet (1 m) tall in USDA zones 5-9. The plant needs full sun and well-draining soil. It looks its best in containers, ornamental flower beds, and borders. But take care to keep dogs and cats away, since the plant is toxic.

You can find live Shasta daisy plants for sale online from Burpee.

6. Oriental Poppy

There are many different types of poppies that you can plant in May, but Oriental poppies (Papaver orientale) are among my favorites. These perennials light up the garden in spring with large, brilliantly-colored flowers made up of petals that look like crepe paper and have a dark blotch at the base.

I’m a traditionalist. So I prefer the orange cultivars, although the red ones come in a close second. But you can find a bunch of other shades to suit your garden palette as well. I love the way the buds droop when they appear, then rise to stand up straight as the flowers open.

Keep in mind that these plants don’t thrive during hot summers. They do well in USDA hardiness zones 3-9 and are fast-growing flowers, but they love the cooler weather of spring. Their show is spectacular, but fleeting. Keep poppies away from curious cats, dogs, and kids.

You can get live Oriental poppy plants from Home Depot in show-stopping red.

7. Delphinium

Look out for the biggest, boldest blooms of summer! Delphiniums (Delphinium elatum) are perennials that can grow taller than you are, up to 6 feet (2 m) tall. They flower from late spring and keep on blooming all summer long, which is one of the reason they were named the flower of year for 2026. Traditionally the flowers are blue, but other shades of pink, purple, and white are available as well.

Delphiniums do best in areas with long, cool springs. They thrive in USDA hardiness zones 3-9. Once again, these are gorgeous flowers that are toxic to people, pets, and horses.

Shop magically beautiful delphinium plants and seeds from Lowe's.