Salvias and alleopathy
Continuing a debate from the CA forum, Salvia leucophylla, Salvia apiana, and other native xeric sages as well as other Lamiaceae members, such as Artemisia californica, are considered by many to be "alleopathic".
Terpene chemicals present in the resinous foliage and fallen leaves of chaparral shrubs inhibit germination of wildflower seeds, a phenomenon known as allelopathy. Fire destroys these inhibitory chemicals that have leached into the soil, and explains the abundance of wildflowers in recently burned chaparral.
Have any of you long-time sage growers noticed this around certain sages? I can't say I have, but haven't really looked that closely either - the bermuda grass still grows under my white sages, but I can't think of too many volunteer annuals that have.