"a riot of color, of poppies and irises"

 Poppies come in many colours and are popular in gardens due to their bright flowers.

Yellow California Poppy
GNU Free Documentation LicenseYellow California Poppy - Credit: Santosh Namby Chandran

Irises take their name from the Greek for rainbow and they come in a variety of colours with very showy flowers.

Iris Sanguinea
GNU Free Documentation LicenseIris Sanguinea - Credit: BS Thurner Hof
Iris Samurai Warrior
GNU Free Documentation LicenseIris Samurai Warrior - Credit: KENPEI