Plants that bloom in September in Zone 10 with blue flowers

Bird of Paradise

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

Borage

Star-shaped electric blue flowers that bees go absolutely wild for. Self-sows freely.

Butterfly Bush

Long, arching flower wands that butterflies absolutely lose their minds over.

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.

Hydrangea

Massive mophead blooms that shift color with soil pH. Showstoppers.

Morning Glory

Fast-climbing vine with trumpets that open fresh every morning.

Pickerelweed

Spikes of violet-blue flowers above glossy arrow-shaped leaves. Native pond and stream bank staple.

Rose of Sharon

A cold-hardy hibiscus shrub (Hibiscus syriacus) with big tropical-looking blooms in lavender, pink, blue, white, or wine, opening late summer when most flowering shrubs are done.

Salvia

Vertical flower spikes that hummingbirds and bees cannot resist.