May Flowering Perennials

USDA Zone 2

• The central portion of the thimbleweed's flower gives this perennial its name, resembling a thimble with its raised stature. This perennial handles the cold winters associated with U.S. Department of Agriculture plant hardiness zone 2, blooming from April well into May. Fleabane turns out flowers similar to small daisies, with May the height of the perennial's blooming period. Fleabane approaches 30 inches in height. The woodland white violet grows only to 6 inches but blooms during May and works as ground cover or in rock gardens in this hardiness zone.

USDA Zone 4

• USDA zone 4 experiences some wild and chilly winters but offers less hostile growing conditions to perennials in terms of cold than zones 1 through 3. This allows more perennials the leeway to grow, with several blooming during May. Among them are species such as bugleweed, windflower, columbine, sea thrift, goat's beard, astilbe and many types of indigo. The lanceleaf coreopsis is a May bloomer throughout this zone, growing in dry soils with little effort. The trumpet honeysuckle is a perennial flowering vine, blooming in May and attracting hummingbirds with its tubular flowers.

USDA Zone 7

• The northern portions of the Deep South, as well as sections of states such as California, Utah and Nevada, fall within USDA zone 7, a warmer area where perennials thrive. Various iris species bloom during May in zone 7; the "Eye of the Tiger" hybrid grows to 24 inches in full sun and starts blooming by May. Cupflowers, beebalms, mints and several types of daisies are May bloomers within zone 7. Fiveleaf akebia is a 20- to 40-foot perennial vine that is a native of Asia but survives in zone 7. It blooms in May and is semi-evergreen to evergreen, depending upon the severity of the winter weather.

USDA Zone 10

• Those seeking May blooming perennials in the warmth of USDA zone 10 find their choices limited because of the ability of plants to withstand oppressive heat and humidity. Astericus, snapdragons, twinspur, fanwort and assorted begonias are up to this task. The lemon daylily stands out among others of its genus for its early bloom period, flowering in May with its yellow blooms. Water gardens in zone 10 support the floating heart, a water lily blooming from May into September. This aquatic plant grows along the edges of ponds as well.