What's Blooming in May: Zone-by-Zone Guide

May is the month the garden stops promising and starts delivering. April teased with early bulbs and flowering trees. May opens the floodgates. Peonies, iris, roses, and lilacs all hit their stride, and for two to three weeks most of the country sits at the absolute peak of the flowering year.

But peak looks different depending on where you stand. In zone 4, May is when spring finally shows up for real. In zone 9, it is the last civilized month before summer heat flattens everything. Here is what is blooming right now in your zone, and what is stepping forward next.

Zones 3-4: Spring, finally, truly, here

Cold-zone gardeners wait all year for May. The ground is workable, frost danger is winding down by mid-month, and everything that slept through winter wakes up at once. The garden goes from bare to blooming in about fourteen days.

Tulips are at their peak right now, or just about. Mid-season and late-season varieties overlap for weeks of color in every shade imaginable. Daffodils are finishing their final wave, and you should resist the urge to cut the foliage. Let it yellow naturally to feed next year's bulbs. Creeping phlox is carpeting banks and rock walls in solid sheets of pink, purple, and white. This is the moment that justifies every dollar spent on spring bulbs the previous October.

The woodland shade garden takes its turn now too. Bleeding heart drapes arching stems with pink or white lockets. Columbine dances on wiry stems in every color combination imaginable, self-sowing into casual drifts if you let it. Lily-of-the-valley opens its fragrant white bells in shady corners, and the scent carries further than the flowers suggest.

The shrubs and small trees are the real show in cold zones. Lilacs perfume entire neighborhoods in mid to late May. If you only grow one fragrant shrub, grow this one. Viburnum opens its creamy white flower clusters, some varieties with a sweet clove scent. Serviceberry and crabapples are covered in blossoms. Azaleas and rhododendrons start their explosion in zone 4 by month's end.

What is coming next: peonies, iris, and roses are budding up now for a late May or early June peak.

Zones 5-6: Peak bloom, every day matters

May in zones 5 and 6 is the best month of the gardening year. This is the stretch gardeners photograph, send to relatives, and walk outside with coffee to examine every morning. The garden changes visibly between sunrise and sunset. Miss a week and you miss bloom sequences you cannot recover.

Peonies are the headline act. Those enormous, ruffled, fragrant heads open over about ten days and the scent stops people on the sidewalk. Stake them early or the first heavy rain will flatten them. Bearded iris is opening in every color imaginable: butter yellow, midnight purple, two-tone apricot, pure white. The flowers last about a week each, so the show moves plant to plant through the month.

Alliums send up their architectural purple globes on tall stems, holding perfectly above the softer perennial foliage. Camassia puts out starry blue spikes in moist meadow spots where tulips refuse to return. Dutch iris opens its elegant blue, white, and yellow flowers on graceful stems, ideal for cutting.

In the perennial border, columbine, foxglove, and catmint are in full swing. Catmint is a billowing blue-purple cloud that will keep going all summer if you shear it back after this first flush. Dianthus covers itself in spicy-scented pink and white flowers along garden edges. Coral bells send up airy wands above their colorful foliage. Baptisia (blue false indigo) unfurls its navy-blue spikes, a tough native that lives for decades once established. Lupines are at their peak in zone 5, with their dramatic bicolor spires.

Azaleas and rhododendrons hit their peak in zone 6 in early to mid May. Entire shrubs disappear under flowers so dense you cannot see the leaves. Viburnum, Kerria, mock orange, weigela, and spirea are all blooming or about to. Mock orange in particular is a fragrance bomb, with a citrus-sweet scent that fills a corner of the yard. Wisteria drapes pergolas in cascading lavender chains, and the bees lose their minds over it.

Roses are budding hard and the earliest will open by month's end. What is just finishing: tulips, daffodils, and most of the early bulbs. What is coming: the full summer perennial border, starting with salvia, the first daylilies, and the first hydrangea blooms.

Zones 7-8: Early summer energy

May in zones 7 and 8 reads more like early summer. Spring bulbs wrapped up in April. The garden has moved on to the perennials and shrubs that carry the show until the serious heat arrives in June or July.

Roses are in full, drenching bloom. This is their best month of the year, before humidity and blackspot settle in. Climbers cover arbors, shrub roses mound themselves into color, and hybrid teas push their most perfect flowers of the season. Peonies are opening in the first half of May and finishing by the end. In zone 8, they are mostly done by mid-month, which is why peonies are frustrating to grow in the Deep South.

Bearded iris is peaking early in the month. Catmint has become the blue-purple backdrop the entire border is built around. Salvia sends up its first flush of red and purple spikes, and it will keep doing so until frost. Lavender opens its fragrant wands, and the bees arrive within hours. Dianthus, coral bells, and baptisia are all blooming together, and the effect is the kind of layered, full-border look that takes ten years to develop.

Daylilies are budding and the earliest varieties are starting to open by month's end. Coneflower and bee balm are not far behind. Hydrangeas are leafing out hard and forming buds, with the first blooms appearing on reblooming and oakleaf varieties by late May in zone 8. Oakleaf hydrangea in particular puts on a spectacular show with its creamy white conical flower heads.

On the shrub front: mock orange, viburnum, and weigela are all flowering. In shade, astilbe is opening its feathery plumes in pink, white, and deep red. The garden is shifting from the cool pastels of spring to the bolder, saturated colors of summer. It happens fast.

Zones 9-10: The last civilized month

May in zones 9 and 10 is when the heat-loving plants take full control. Spring was February and March. Summer starts in earnest by June. This is your last month of comfortable weather, and the garden knows it.

Roses are at their spring peak. By mid-June the heat will slow them down, and they will not look this good again until fall. Cut them freely and enjoy them while they last. Salvia, lantana, and coneflower are all going strong, happy with rising temperatures. Daylilies are opening. Bougainvillea is covering walls, fences, and pergolas in hot pink, magenta, and orange.

Hydrangeas are in full bloom in zone 9, with mopheads and lacecaps at their best right now. Oakleaf hydrangea is especially spectacular. Gardenia is opening its intensely fragrant white flowers in the Deep South, and the scent alone justifies growing it. Cardinal flower is starting to show up in moist spots, drawing hummingbirds with its scarlet spikes.

Zone 10 gardens look more tropical by the week. Plumeria, hibiscus, and mandevilla are in full flower. Citrus is still finishing its fragrant bloom cycle. This is the last comfortable month before real heat arrives. Water deeply, mulch heavily, and get any remaining spring planting wrapped up by the end of May. Anything planted in June will need significantly more babysitting to survive the summer.

What to do in May

Stake tall perennials before they flop. Peonies, delphiniums, and tall iris all benefit from support installed now, while the foliage is still short enough to hide the stakes. Once the plants reach full height and fall over in a rainstorm, it is too late.

Deadhead finished tulips and daffodils, but leave the foliage until it yellows naturally. Pulling green leaves cheats next year's blooms. Shear catmint, creeping phlox, and basket-of-gold after their first flush. You will get a smaller second bloom and much better-looking plants all summer.

Fill the gaps. May is the single best month of the year to shop at a nursery in most zones. The selection is enormous, the plants are healthy, and what you buy now still has time to establish before summer heat. Walk your garden, note every spot that is currently bare, and find plants that bloom during the months you are missing. A garden that flowers from April through October is always the result of someone standing in the garden in May saying "I need something here for August."

What comes next: the first daylilies, the first hydrangeas, and the summer perennial backbone of coneflower, bee balm, phlox, and salvia. See our guide to what is blooming in June and what to plant right now. Browse our Fragrant Flowers and Pollinator Powerhouses collections for more ideas.

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For a month-by-month chore checklist tailored to your USDA zone, see our garden chores by zone guide.