This wine-producing region north of San Francisco, located in U.S. Department of Agriculture Plant Hardiness Zone 9, has cool nights and little humidity, and the February to November growing season is long. Fruits that need winter chilling—a set number of hours below 45 degrees Fahrenheit—do well in Sonoma County, including many stone fruits, which have similar requirements as the grapes that blanket the county.
Most varieties of apricots, which are a member of the Rosaeace family, thrive in Sonoma due to the long, hot summers, cool winters and limited rain, which may interfere with pollination. The trees grow to about 15 feet, produce fragrant flowers before giving way to small, yellow, fuzzy-skinned fruit in late spring to summer. The fruit is about the size and shape of an egg and has firm, sweet, yellow flesh and a small pit.
Apricot trees require little maintenance as fruit grows on old branch spurs. The trees should be planted in full sun and get periodic soakings.
The American persimmon (Diospyros virginiana) is native to much of the eastern and southern United States but grows well in Sonoma. The trees, which do not require cross-pollination or chill time, can grow to 60 feet. Since the persimmon tree can form thickets of root suckers, it is more appropriate for a wild garden or a large property that is not formally landscaped.
Persimmon trees produce a round, glossy fruit that may have yellow or orange skin and sweet, juicy flesh. Fruit may be harvested when it is soft, usually near the first frost.
Persimmon trees should be planted in full sun and require regular to moderate water. They are not fussy about soil.
Several varieties of plums, including the damson (Prunus insititia) and green gage (P. domestica italica), thrive in Sonoma, because the fruit ripens best with less heat in the summer. The damson plum is ready to harvest in late August to September and produces a small fruit with smooth blue-black skin and tart, green flesh. The green gage is an older variety that produces a medium-sized fruit with smooth, green-yellow skin and sweet, light yellow flesh. This variety is ready for harvest in the middle of the season, usually in July to August.
In general, plum trees should be planted in full sun and need periodic deep soaking of the roots. The trees will tolerate bad soil but thrive in fertile, well-draining soils.