By Susanne von Rosenberg, UC Master Gardener of Napa County
Have you been thinking about adding a fruit tree or two to your garden? December and January are the best times of year to plant deciduous fruit trees. (Citrus trees are best planted in late spring, after the threat of frost has passed.) In December and January, local nurseries have a wide variety of bare-root fruit trees available. Bare-root fruit trees are less expensive than comparably sized trees in pots, and they are easier to plant. Here are some considerations for choosing the perfect tree or trees for your garden.
The first consideration, always, is what kind of fruit do you enjoy? I have more than 20 fruit trees, but no peaches. I don't like the fuzzy skin so I prefer nectarines.
The next consideration is whether you primarily want fruit for fresh eating, or whether you also intend to preserve a portion of your harvest. How much fruit you want will suggest how large a tree you need. Even a small tree (five feet in height and with a five- to six-foot diameter crown) can easily provide 50 or more fruits several years after planting. That may not sound like a lot, but it's enough for a small household for a month. Depending on the variety, a tree that is only a bit larger can provide as much as 100 fruits.
For most gardeners, it makes sense to keep trees on the small side. You can do that by pruning the tree regularly. Semi-dwarf or dwarf trees will need less pruning than standard size trees. Smaller trees are easier to care for because you won't have to get on a ladder, and they also require less water and fertilizer.
When you keep trees smaller, you have room for more trees. That means you can spread out the harvest period (for example, you can plant early, mid-season and late apples), or you can plant more types of fruit. With proper pruning, you can fit five or six trees into a 30 – by 7-foot space.
It's best to buy your trees from a local nursery. Fruit trees are typically grafted, with the fruit-bearing part (the scion) grafted onto a rootstock that is appropriate for a specific area. Different types of rootstocks are suited to different soils and have different kinds of disease resistance. When you buy a fruit tree locally, it is grafted onto a rootstock suitable for Napa County. Equally important, the trees in our local nurseries have been inspected to make sure that they are not harboring invasive pests.
The third consideration is your location. Different parts of Napa County vary in the number of annual chill hours they get, with Carneros receiving the fewest and the Lake Berryessa and Pope Valley areas having the most. Chill hours are the number of hours each year between 32°F and 45°F. Fruit trees require a minimum number of chill hours to produce well. The number of chill hours varies dramatically by variety. Granny Smith apples require 900 chill hours, while Anna apples require only 200 to 300.
The number of chill hours in all areas is projected to decline with climate change. Your trees will not suffer if they receive more chill hours than required, so look for varieties requiring fewer chill hours. You also need to verify that you have adequate sunlight; fruit trees need at least eight hours per day. If you are in a windy location, make sure that the variety you want to plant isn't sensitive to wind.
Next, find out whether the variety you're considering is self-fertile, semi-self-fertile or requires a pollinizer (another variety of fruit tree that provides pollen to fertilize the flowers). Self-fertile trees do not require a pollinizer. Semi-self-fertile trees will set fruit without a pollinizer but will yield more fruit with one nearby. For trees that require a pollinizer, the label will indicate which varieties will do the job.
If you don't have room for the pollinizer, see if someone in your neighborhood has the correct variety.
Depending on the type of tree, the pollinizer may need to be as close as 70 feet or can be as far away as 250 feet. Some labels provide this information. If not, check with the nursery or investigate online. As an alternative, you can ask someone who has the desired pollinizer to give you a few branches when they flower. Put the branches in a vase and prop them up in your tree. You can also graft the pollinizer variety onto your tree.
Keep these considerations in mind, and you'll be successful in picking the perfect fruit tree or two for your garden.
Up coming events: “An Apple a Day: Choose the Right Apple for You and Your Garden” on Thursday, January 2, from 7 p.m. to 8 p.m., at the Napa Library, 580 Coombs Street, Napa. The talk is free and no RSVP required.
“Rose Pruning and Winter Care” on Saturday, January 11, from 10 a.m. to 12 noon at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Join the UC Master Gardeners for this interactive forum and workshop. Reserve your spot for only $5 for reservation and more details go to http://ucanr.edu/2020rosepruning or call 707-253-4221.
The UC Master Gardeners of Napa County are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.