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Gardening: Blueberries for Puget Sound gardens


Large, luscious blueberries are easy to grow in Western Washington.

gardening by Chris Smith, Kitsap County Cooperative Extension
On the steepest slopes of our pasture where grazing cattle seldom visited, blueberries grew among the juniper and bayberry. As a boy, I picked many pies, cakes, and muffins worth from that fragrant New England hillside.
   Picking enough of those small, wild, low bush berries for a pie took time, but the pies justified the labor. Freshly baked, they'd perfume the whole house with their heavy, spicy scent. For dessert with a scoop of vanilla ice cream or for breakfast the next day, a piece of blueberry pie was the distillation of summer's fragrance and sweetness.
   I first tasted cultivated blueberries called "high bush" after our family moved to the midwest. They had little of the aroma and sweetness of their wild cousines.
   Blueberry breeders, though, have made progress since I was a kid. There are now cultivated varieties with good aroma and flavor. While they don't rival the wild berries, they're far from bland, and you can pick enough for a pie in a few minutes.
   High bush blueberries grow well in western Washington. Cousins to azaleas and rhododendrons, they thrive in the same acid soils preferred by those plants. They may not put on a floral show like their ornamental relatives, but blueberries compensate with spectacular scarlet foliage in fall.
   Convinced you should put in a few bushes? If so, early spring is an ideal time for the job. Select a sunny site if possible, though the plants will grow in partial shade. And avoid frost pockets (low spots where late spring frosts can ambush blossoms).
   Consider also the soil where you plan to set your bushes. Though they'll grow on mineral soil, blueberries do best on moist, organic soils with a pH between 4.5 and 5.5. A low, almost boggy spot will grow blueberries. Add peat or other organic matter. And if the soil pH is above 5.5, adjust it with sulphur. Soil already growing healthy rhodies is probably sufficiently acidic to suit blueberries.
   Cultivated and blueberry varieties are self-fertile. However, they produce more bountiful crops when they receive pollen from another variety. So plant several kinds.
   In order of ripening, the following are among the varieties recommended for this area (starred varieties are reputed to be the most flavorful and aromatic: Earliblue, Spartan,* Blueray,* Ivanhoe,* Concord, Berkely, Bluecrop, Pemberton, Herbert,* Jersey, Coville,* Dixi,* Olympia,* and Elliott. Spartan and Elliott are resistant to mummy berry, a common fungus disease. Two dwarf varieties, Northsky* (18 inches high) and Northblue (3 feet high), may interest gardeners with limited space.
   Set regular high bush varieties six to eight feet apart. When mature, they may reach seven feet in height with a spread of four to five feet.
   Once planted, blueberries need regular attention to mulching, fertilizing, watering, and pruning. None of these chores, though, takes much time in a family-size planting.
   Spread an inch or two of moisture-conserving, weed-discouraging mulch at planting time and increase to six inches as the bushes mature. If you use fresh sawdust or bark, add nitrogen fertilizer to compensate for tie-up of that element by the microorganisms decomposing the mulch. You'll need 3.5 pounds of nitrogen per cubic yard of fresh, woody mulch.
   In fertile soil, blueberries may not need fertilizer. Check the new shoots each year. If growth is a foot or more, you can skip the fertilizer. However, if shoot growth is scanty and the leaves abnormally small, fertilizer may help. Fertilize in spring when leaf growth begins. Start with a quarter cup of 5- 10-10 per plant. Increase by a quarter cup per year to one and a half cups for 6-year and older plants.
   Assume your bushes will need between one and two inches of water every two weeks. Most of the year they'll get it naturally from rainfall. In the summer, though, you may need to irrigate at two-week intervals. If blueberry bushes dry out, they do not thrive.
   Blueberries usually don't need pruning until they're three years old. Then prune out weak, twiggy growth and nip low hanging branches every spring. This pruning will stimulate the formation of new shoots which produce fruit buds for the following year. On ancient bushes, cut out old woody growth to strong laterals.
   If you plant your bushes this spring, in a few years you'll be enjoying pies, cakes, muffins, and syrup on the table and some fiery color in your fall landscape.