Marin IJ Articles
September 24, 2007
By Marie Narlock
Call out box:
Marin gardeners are invited to join author and Sacramento County Farm Advisor Chuck Ingels on October 4 from 7:30 to 9 p.m. at the Marin Art and Garden Center. Ingels will discuss all aspects of selecting and growing fruit trees. He is the lead author of The Home Orchard: Growing Your Own Deciduous Fruit and Nut Trees (Univ. of Calif. pub. no. 3485.) This presentation is sponsored by the UC Marin Master Gardeners. Cost is $5.00 at the door. No reservations required.
There are a lot of good reasons to own a fruit tree, but probably the worst is, “I saw it at the nursery and it looked so cute that I just had to have it.”
It’s a bit like choosing a spouse. Pick the right tree and if you’re lucky you’ll have a partner for life. Choose the wrong tree and you may want to chop it down after a few years.
Selecting a fruit tree takes planning and research. First, gardeners must honestly assess their microclimates. Deciduous fruit trees require a certain cumulative number of hours at or below 45 degrees F every winter to end their dormancy and then flower and bear fruit. This is known as “chilling requirement.” Most areas of Marin receive around 800 to 1,000 hours of chill every winter which is enough for most fruit trees, but this will vary from town to town and microclimate to microclimate. Areas with significant marine influence will receive the least chill; inland areas will have the most. Luckily, for those in borderline areas there are many varieties of “low-chill” fruit trees on the market today.
Second, summer warmth is an important consideration. Peaches and nectarines love a long hot summer. Apples like warm days and cool nights (think Sebastopol). Apricots, cherries, and pears will perform in somewhat cooler summer areas, but not right on the coast. Figs and persimmons aren’t too picky, but will be tastier with summer warmth.
Some Marin microclimates are bipolar: Corte Madera, Mill Valley, and Tiburon, for example. Usually these areas have sufficient chill in the winter and warmth in the summer. But some years are downright wacky. If in doubt, choose low-chill and early harvest varieties.
Sometimes an area has all the right winter and summer requirements but is also plagued by late rains, wind, or fog. This can hurt or knock off growing buds or inhibit pollination. Here again, “low-chill” varieties may be beneficial because their buds will be more developed and less likely to be affected by the elements. In general, the stone fruits (peaches, nectarines, apricots, cherries, and plums) don’t respond well to extremely wet springs.
Another factor to consider is mature size. Fruit trees are available in dwarf (8 to 10 feet), semi-dwarf (10 to 20 feet), and full size (20 feet and over). For harvesting, dwarfs and semi-dwarfs make a gardener’s life much easier. If shade and ornamental value are more important than space considerations, then perhaps a full-size specimen is the best choice.
Disease resistance is critically important. Marin’s climate is damp, and high humidity provides the perfect breeding ground for pathogens such as fungi and mildew. Choose apple and pear varieties that are scab or fire blight resistant. Apricots are susceptible to many pests and diseases, including scale insects, brown rot, and bacterial leaf spot. Cherries are prone to brown rot and cracking fruit, especially in wet areas. Pears and apples are often hosts to codling moths. Peaches and nectarines are painfully susceptible to peach leaf curl and may also succumb to brown rot. Plums, persimmons, and figs are naturally more disease resistant.
Fruit trees appreciate full sun and fertile, well-drained soil. For gardeners with less than ideal soil conditions, the rootstock becomes an important decision point. The rootstock of a fruit tree is the roots and bottom onto which the scion is grafted. The scion contains the genetic material that guarantees that every ‘Fuji’ apple tree will have the same type of fruit. It’s the part of the tree we see and enjoy. The rootstock is the underground workhorse. Most fruit trees are grafted onto rootstock which is often selected for its disease resistance, dwarfing, and specific soil conditions such as heavy clay or sand. If slow-draining soil that cannot be amended is a concern, consider finding a rootstock that can handle it.
Some fruit trees must cross-pollinate for fruit to develop. When cross-pollination is required, it is necessary to have a particular companion pollinating tree or shrub nearby. Many pear and cherry trees require that a particular variety of tree be nearby as a pollinator. For instance, ‘Bing’ cherries like having a ‘Black Tartarian’ cherry tree nearby for cross pollination and ‘Bartlett’ pears often need a companion. Buying two trees instead of one can be impractical because space in Marin backyards is often at a premium. Best to choose self-fertile varieties whenever possible—these are readily available. Occasionally a neighbor will have an appropriate tree. As a rule of thumb, if you can see the potential pollinator from the site of your new tree, then it’s probably close enough for effective pollination to occur.
While in the fruit tree planning and selection phase, be sure to find a reputable pruner. Pruners are sort of like a fruit tree’s dentist. This is because fruit trees require two check ups per year: one in winter to prune while dormant, and one in summer to shape and trim. Adhering to this schedule assures that branches will not be snapping off under the weight of fruit. It also means that your tree will be attractive all year, whether you’re admiring its springtime blossoms, harvesting fruit in summer, or enjoying its shade during Marin’s warm autumn months.