Plants that bloom in May in Zone 10 with blue flowers

Ajuga

Bronze-purple foliage with blue spikes. Fills bare shade in one season.

Anemone de Caen

Poppy-like flowers in jewel tones bloom in mid-spring over ferny foliage.

Bachelor's Button

True cornflower blue that almost no other flower can match. Cottage garden classic that self-sows reliably.

Bird of Paradise

Sculptural, crane-like flowers in orange and blue. Unmistakable.

Blue False Indigo

Lupine-like spikes on a native that lives forever. Gets better with age.

California Lilac

Electric blue flower clusters on an evergreen California native. Hummingbird and bee magnet.

Catmint

Billowy lavender-blue haze that blooms all season if you shear it back.

Clematis

The queen of flowering vines. Over 300 species, something for every spot.

Creeping Phlox

An evergreen sun-loving groundcover that smothers walls, slopes, and rock gardens in dense pink, purple, blue, lavender, or white sheets every April and May.

Iris

Elegant sword-leaved perennials with intricate, ruffled blooms.

Larkspur

Tall spires of spurred flowers in deep blue and purple. The annual cousin of delphinium, easier to grow from seed and just as dramatic.

Nigella

Sky-blue flowers wreathed in feathery green bracts give way to ornamental striped seed pods. Self-sows freely once you start.

Plumbago

Sky-blue phlox-like clusters bloom nonstop in warm climates. The blue flower that thrives where most blues melt in summer heat.

Rosemary

Aromatic evergreen herb with tiny blue flowers loved by early bees. Needs excellent drainage.

Salvia

Vertical flower spikes that hummingbirds and bees cannot resist.

Texas Blue Star

Fine foliage and pale blue starry flowers are followed by golden fall color.

Triteleia

Loose umbels of starry blue trumpets on tall wiry stems. Western native bulb that thrives on summer drought.

Vinca

Evergreen mat with periwinkle-blue flowers. Tough shade ground cover.

Wisteria

Cascading, fragrant racemes that create a dreamy canopy. Needs structure.