There are definitely some flowering shrubs that seem to be preferred by hummingbirds as food sources. There are species of Grevillea, Zauschneria and Agastache that hummingbirds find very attractive. Cape honeysuckle (Tecoma sp.), bottle brush (Callistemon sp.), Alstromeria and Pelargonium sp. are also favorite feeding stops on the hummingbird foraging route. Albizzia sp., foxglove (Digitalis sp.), Azalea sp., Trumpet Vine (Compsis sp.), Beebalm, Delphinium, Hollyhock, Lantana, Fuchsia, Cardinal Vine (Ipomoea sp.), and Rose of Sharon are all listed as good sources of nectar for hummingbirds, and that will grow on the Central Coast. The list goes on, so I suggest you go to your computer, type “hummingbird food plants” and then select from the list of many species those that will fit into your landscape design and color scheme.
If you wish to supplement the natural food sources with hummingbird feeders, the following recipe is suggested from a University of California publication: One part sugar to three to four parts very hot or boiled tap water. Shake or stir until the sugar is completely dissolved. Fill feeder only with enough to last 2 days, and store the rest in the refrigerator. Clean the feeder every 2-3 days, using very hot water, perhaps with a little bleach. Detergent may be used, but do not use detergent and bleach together. Rinse very thoroughly. In warmer weather (above 65 degrees F.) more frequent cleaning is required as pathogens multiply faster. Refill feeder with a fresh sugar solution.
An old recipe suggested the addition of a small amount of non-dairy nutritional supplement. This is no longer recommended. Wild hummingbirds do not need the added supplement, and this additional food could create problems for the birds if they eat too much of it, or if it is the wrong type of supplement.