Cneoridium dumosum, Bush Rue, in flower.
By Clayton Tschudy.
The Mediterranean climate of San Diego carries the reputation of year-round garden blooms, the forever spring of a warm temperate environment. While our seasons are more complicated and subtler than those of more northerly climes, it is actually true that there is a blooming native every month of the year in San Diego. And in January the stand-out bloomer is the native Bush Rue, Cneoridium dumosum.
Cneoridium dumosum, Bush Rue, flower close-up.
This diminutive woody shrub, often only 2’ by 2-3’ wide, occurs from the coast to the foothills in a variety of soil types, and like many natives can be nondescript in the hot months. Under heat stress it will partially defoliate, sometimes developing a golden red coloration in the remaining stressed leaves. But following winter rains this little trooper will burst into exuberant bloom looking for all the world like a weird, miniature orange tree. And yes, it is in the orange family and produces tiny orange fruits! A word of caution, the fruits are NOT edible, and like some other members of the orange family, the leaves are coated in essential oils that are phototoxic. This means exposure of the skin to the oils, then followed by sun exposure, can lead to serious dermatitis. So, wear gloves while handling, and place the shrubs away from casual contact zones.
This plant has a reputation for being difficult to establish in gardens, which is strange as it occurs naturally in many soils and microclimates. My recommendation is to plant it in the fall only, as it expresses strong dormancy in summer, and plant it in native dirt only. Plan on turning off the irrigation permanently after the first summer. Then be patient. Bush Rue is slow, but rewards with years of life, and a New Year surprise just when you least expect it.
Clayton Tschudy is the Executive Director of San Diego Canyonlands.