UNITED STATES—Cool season annuals are less diverse than warm season annuals for one simple reason. Flowers prefer to bloom while their favorite pollinators are most active. Most of the better pollinators are insects that are most active during warm weather. Therefore, most flowers want to bloom while the weather is warm. Many colorful berries are similarly exploitative.
For dispersion of their seed, colorful berries rely on birds. Therefore, many ripen and are most colorful as many birds migrate during autumn. Birds consume the berries but do not digest their seed. Instead, as they migrate, they disperse the viable seed. It is a mutually beneficial arrangement. Birds eat all they want. Seed benefits from thorough dispersion.
As they ripen, autumn and winter berries develop bright colors that attract birds. Most are bright red. Some are bright orange. A few are bright yellow. They are substantial enough to satisfy the birds that eat them. Yet, they are compact enough for such birds to eat them whole. Some are impressively abundant, at least until any birds that they feed find them.
Colorful berries are literally for the birds.
That can be a dilemma for home gardening. Many garden enthusiasts grow autumn and winter berries for the color. Many grow them to attract birds, though. More grow them both for their color and to attract birds. The latter is least disappointing. Typically, such berries ripen to display their color faster than birds can eat all of them. Every season is different.
Unfortunately, there are not many options for colorful autumn and winter berries. Some of the species that produce the most colorful fruit are unfortunately thorny. Firethorn notably produces the most abundant, most colorful and most familiar berries. It is horridly thorny, though. So is English hawthorn, which is deciduous and defoliates to expose its red fruit.
Toyon and various cotoneasters are thornless alternatives for colorful berries. Toyon is a native species that grows rather large. Although cotoneasters are not as prolific, cultivars stay proportionate to home gardens. Hollies are dioecious, so female specimens need a male nearby for pollination. Because males are rare, females produce only a few berries.
Highlight: Firethorn
Nothing is lost in translation. The botanical name of Pyracantha coccinea literally means “Firethorn red”. Firethorn is its common name. It produces bright red berries on wickedly thorny stems. Some old-fashioned cultivars produce bright orange berries. Cultivars that produce bright yellow berries are now rare. Fruit ripens for migrating birds about autumn.
The thorns of firethorn are difficult to work with. However, they make a hedge of firethorn impenetrable. Frequent shearing deprives hedges of their natural form and some of their fruit. Selective pruning is tedious and likely painful, but retains more berries. Pyracantha needs sunny exposure, but is otherwise quite undemanding. It is susceptible to fireblight.
The most popular cultivars of firethorn can grow taller than eight feet. Taller cultivars that can grow twice as tall are uncommon. Sprawling types initially stay quite low, but without adequate pruning, form thickets. These same sprawling types are conducive to espaliers on fences and walls. Because pyracantha is difficult to work with, it should not be left to get unruly.
