Plant of the Month (brought to you by Golden West College Native Garden)
Umbellularia californica- California bay laurel
Type: Evergreen tree or large shrub.
Light: Likes full sun but can get by with light shade.
Soil: Good draining but enjoys soils that retain moisture.
Water: Enjoys water but once established it can tolerate drought conditions.
A tree commonly found in much of California, it is also a native here in Orange County being found in the Santa Ana Mountains. A member of the Laurel family (Lauraceae), California bay laurel shares its family with Grecian laurel and avocado. In fact the small fruit remind me of tiny avocados and although they are reportedly edible-I have not yet tried them. Nor have I tried the nut (similar in shape to an avocado pit) which some people find good when roasted. The leaf is known as a very strong version of the European bay leaf (Laurus nobilis) and it can be used in cooking but at half strength or less.
Hikers may smell the intense aromatic fragrance before they even see the tree itself. When rubbed or crushed, they emit a pungent odor reminiscent of the bay leaf of culinary fame but typically with a much stronger scent. This odor is due to the oils present in the leaves, which contain up to 40% umbellulone, an aromatic ketone compound. The laurel leaves have been used for centuries by Native Americans to treat headaches and sinus congestion. Use too much however and you can increase instead of cure you headache-I have done it! It has yellow-green blossoms which are almost too small to be noticed but occur in fragrant clusters in late winter (and grow in stalked umbels – giving rise to the genus name Umbellularia, which means “little umbel”). In addition, with its green glossy leaves, and a nice multi trunked form the California bay is a beautiful tree.
In the GWC Native Garden we have two of these trees, a thirty foot specimen is planted in the Mixed Evergreen Woodland and a smaller, younger tree in the Foothill Woodland. I am expecting them to eventually get up to around forty to fifty feet in the Garden, although in favorable locations in the wild they can reach 100 feet tall! These trees are also known to produce a broad basal burl which resprouts after fire or other damage to the tree. Not too much bothers this plant although Laurel aphids often get on the leaves. They secrete a sugary honeydew which causes sooty mould to form on the leaves and almost anything beneath the tree. Washing the underside of the leaves (wear a raincoat) with a horticultural soap spray helps as does preventing the aphids ally ants, from climbing into the tree.
Besides the obvious use as a lovely tree in garden situations, the bay can also be used as a tall screen or clipped hedge. This very adaptable plant (sun/shade, water/ drought, loam soil or clay, upright tree or clipped hedge) is a wonderful plant for your garden.