By Bob Labozetta (UC Master Gardener, Mariposa)
December to March is the best time to plant fruit and nut trees here in California. Selecting appropriate fruit trees, however, can be confusing. Impulsive purchases can lead to disappointment, particularly in the foothills where not every variety grows well.
The key to success when it comes to fruit and nut varieties is to buy local. Talk to knowledgeable employees at a local foothill nursery. Tell them about your property (including elevation, sun, etc.) to get the best advice. Trees at your local nursery may be slightly more expensive, but they have been chosen specifically for the foothills.
In narrowing down specific varieties, consider size and chill hours.
Fruit trees commonly come in standard, semi-dwarf or dwarf sizes. Dwarf fruit trees generally produce poorer quality fruit. Standard size trees are too large for most backyard orchards and more difficult to prune. Semi-dwarf fruit trees are the best combination of fruit quality and ease of care. In any case, both semi-dwarf and standard trees can be dwarfed by proper pruning and training.
Vernalization or “chill hours” refers to the cumulative number of hours with temperatures below 45°F, which is necessary for a fruit tree to break dormancy and produce fruit in the following season. This requirement varies depending on the variety. In the foothills, temperatures vary widely, so you want to pick varieties that will be successful for your property.
Rootstock is also important to the success of your fruit tree. The tree you select is most likely NOT grown from seed. It is the result of grafting a scion to a rootstock. Rootstock is the base and root portion of a grafted plant. It’s grafted onto the scion of a similar plant, which is the flowering or fruiting part of the resulting union. The goal is to create a new plant with superior qualities. It is commonly used in the production of fruit crops, such as citrus, apples, etc. The resultant plant is a cultivar, or man-made hybrid. When looking at individual trees, make sure that the grafted union of rootstock and scion has healed well.
When selecting trees from a nursery, look for a caliper size (the measurement just above the scion-rootstock union) between ⅜ inches and ⅝ inches. Anything smaller may be characteristically weak; anything larger may result in an imbalance between the top and the root system.
For more information on selecting fruit tree varieties, please go the Resources page on the Master Gardener website at http://cemariposa.ucanr.edu/Master_Gardener/Resources/
UC Master Gardeners of Mariposa County are located at 5009 Fairgrounds Rd., Mariposa. For more gardening and event information, visit their website at http://cemariposa.ucanr.edu/Master_Gardener or on Facebook at UC Master Gardeners of Mariposa County.
UC Master Gardeners staff a Helpline serving Mariposa County, including Greeley Hill, Coulterville, and Lake Don Pedro (209-966-7078 or firstname.lastname@example.org).
Listen to them on the radio at KRYZ 98.5 FM on Wednesdays at 2 p.m. and Saturdays at 5 p.m.