Bloom and colorful foliage provide most of the color besides green within home gardens during spring and summer. Deciduous foliage becomes more colorful for autumn. Winter berries and a few other lingering fruits become more colorful as deciduous foliage sheds through winter. All this color adheres to precise schedules within a collective ecosystem.
Many plants exploit wildlife. It is how they compensate for their immobility. Many provide incentive for the services that they desire from the wildlife that they exploit. For example, after enticing pollinators with fragrance or color, flowers happily exchange extra pollen or nectar for pollination. Many plants provide edible fruits in exchange for seed distribution.
It is no coincidence that so many different winter berries ripen through autumn for winter. They provide sustenance to many migratory birds who rely on them. Overwintering birds who compete with migratory birds appreciate their efforts as well. Such winter berries are small but abundant, for ‘grab and go’ convenience. Bright color is the best advertisement.
Some people appreciate how winter berries attract birds and squirrels into their gardens. Some appreciate the seasonal color of such berries more than the wildlife. Unfortunately, wildlife decides the outcome, and such outcomes are variable. It is impossible to predict if berries will disappear as they ripen, or linger as they deteriorate through most of winter.
Firethorn is likely the most familiar of the winter berries here. It seems to be more prolific with its brilliant red berries than any other species. Some old fashioned cultivars produce bright orange or perhaps even bright yellow berries. Some sorts of cotoneaster resemble firethorn, but with subdued rusty or orangish red display for less refined woodsy gardens.
Toyon, or California holly, is most prolific with winter berries where it grows wildly without pruning. It gets big though. Real hollies, which are more popular in other regions, do not produce many berries locally, particularly since male pollinators are uncommon. English Hawthorn is a small deciduous tree that displays berries that resemble those of firethorn, but on bare stems.