Plants that bloom in March in Zone 10 with blue flowers

Anemone de Caen

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

Bird of Paradise

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

California Lilac

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

Rosemary

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