Looking for a drought-tolerant, fast-growing, plant that likes clay soil? Plant a ceanothus. Many species of Ceanothus are California Natives. The California Native Plant Society lists 136 ceanothus species native to California. The plant is basically a low-growing shrub but some species like the 'Ray Hartman' can be pruned into a tree. Most of all Ceanothus produces these stunning blue flowers that attract all kinds of bees. Depending on the species flowering can occur from January to late Summer. January blooms are an early source of food for bees when other flowers haven't bloomed. A drawback to the fast growth is the life span is limited to 15 – 20 years.
My first Ceanothus was planted in 2017. It started out in a 1 quart/ liter pot, now it is two feet high and spreads out three feet in all directions. I water it infrequently and it is planted in clay soil. Ceanothus is also a nitrogen fixer (it doesn't need additional nitrogen, it ‘fixes' it from the atmosphere). It needs very little care but now I might have to prune it a bit. Word of warning never prune a Ceanothus in the winter.
The next Ceanothus I planted was a 'Ray Hartman', which is a nursery cultivar of C. arboreus and C. griseus, that grows well in most areas of California. It is not found native in the wild. Planted last year from a 1-gallon nursery pot it now stands 4' high with 2'-3' wide. It can be pruned into a tree with a height up to 15'. It was developed by chance at the Leonard Coates Nursery in Morgan Hill in 1929. It is easy to grow and it grows fast.
Recently I purchased a Ceanothus 'Dark Star' it has these small dark green leaves and according to the plant tag description it will have “dark cobalt flowers with yellow stamens.” It's a shrub and can grow up to 6' high and 8' wide. My goal is to have a variety of bee-friendly Ceanothus species and other plants in my front garden that will attract bees year-round. If you want to bee-friendly plant a Ceanothus.
Source materials from:
-California Ceanothus
-Ray Hartman Ceanothus
-Dark Star Ceanothus
UCANR
The Bee Gardener - UC Davis Bee Haven March 3. 2014
Ceanothus, March Bee Garden Plant of the Month by Dr. Christine Casey