Plant it for the Bees: Ceanothus 'Ray Hartman'

Ceanothus 'Ray Hartman' is one of our most reliable, and garden adaptable, native shrubs/trees. This cultivar, is a blending of the coastal, Ceanothus griseus and the Catalina Island tree, Ceanothus arboreus. Developed in the late 1940s it has become a well known and dependable performer in the California coastal garden. Ceanothus griseus gives the leaves of the tree revolute leaf margins and bluer flowers than C. arboreus alone. This vigorous and fast-growing plant can attain 10 feet in a couple of years in my experience, and can

top out at about 20 feet tall and almost as wide. The buds will fool you because they are pinkish, but open to medium blue, large clusters of small flowers, that make you say, "ahhh."A large mature tree in full bloom is a sight to behold, and it will have you calling up local nurseries scrambling to find Ray, otherwise known as, "Mister Dependable." The reason it is an old, widely planted, and commonly occurring ceanothus or California lilac is because Ceanothus 'Ray Hartman' will not "up-and-die" in typical garden watering regimes like other species of Ceanothus are known to do.

Remember, Ceanothus are pioneer plants, and survivors, and for the most part cannot tolerate watering that doesn't resemble the precipitation rates of their native habitats. Ceanothus 'Ray Hartman' seems to be a bit of an exception to this rule--especially--when it is newly planted. It will gladly accept most watering and reward you with luxuriant growth. The fast growth comes at a price, however, and causes problems like shorter life span, wind throw, and the aborted development of strains of the symbiotic filamentous bacteria, Frankia. Ceanothus sp. are actinorhizal plants that fix nitrogen with the help of root-forming nodules of Frankia, much like the more familiar legumes and rhizobium bacteria.

Strains of Frankia are widespread and persistent in California soils even without the host plants being present. They are also important in many other ecosystems where nitrogen is limited. Pioneer plants are important to fix nitrogen, so that other plants can get established in depleted soils. In Southern California, frequent fires deplete nitrogen and Frankia are important to hasten the reestablishment of populations of plants. Studies in southern California have identified 12 distinct strains of Frankia. Climate, geographic location, soil pH, and host species present are all thought to influence the identity of Frankia strains in a given area. Birds and water are known dispersers of Frankia. The bacteria also form relationships with other pioneer plants in the Genera: Alnus, Rhamnus (Frangula), and Eleagnus.  Unfortunately, when Ceanothus are pampered, Frankia have low levels of nodulation, this was shown in several greenhouse experiments that failed to yield the high rates of the sought-after intercellular infection of Ceanothus roots.

High Frankia infection rates improve growth, foliar nitrogen, and survival rates of Ceanothus. Because of this, it may be best to give Ray a little tough love and don't pamper him too much. Ceanothus have a undeserved reputation for being short-lived. Ceanothus tend to live longer and don't flame out at a young age when their irrigation rates are tempered.

While trees in full bloom are the stuff of dreams for humans, bees share that enthusiasm. To see a tree in bloom is to hear the excited buzzing of many bees gorging themselves on the bounty found in the little tiny flowers. Ceanothus are hands-down among the most favored bee plants in the California garden. I grow them as much for the anticipated hum of bees, as for the beauty of the blue corona of flowers. Non-native honeybees, as well as, native bumblebees, and native Halictid bees are big fans, and come from far and wide for an opportunity to partake. In the words of UC Berkeley urban bee entomologist, Dr Gordon Frankie, "Bees adore this plant!" Flowering Ceanothus are excellent and important pollen sources for bees. In my garden I consider it my duty, as well as, my pleasure to provide the finest that nature has to offer for my pollinators--especially for my bees. Ceanothus species do so many things well: they provide ravishing beauty, exceptional pollen for bees, and the fruit feed many species of birds. Plant Ceanothus and instantly attract wildlife that make your garden so much more than just pretty plants!