Blueberries: No Longer a Novelty Plant in the Home Garden
Blueberries are relative newcomers to our gardens; virtually all available cultivars were developed in the twentieth century.
Modern hybrid blueberries are often a cross between highbush and lowbush blueberries. The Horticultural Research Center of the University Of Minnesota’s Arboretum has introduced several modern varieties which include ‘Northblue’, ‘Northsky’, ‘Northcountry’, (which were introduced in the 1980s) ‘St. Cloud’, (introduced in 1990) ‘Chippewa’ and ‘Polaris’, (both introduced in 1996).
Blueberries are usually self-compatible, but when two or more cultivars are planted next to one another, cross-pollination produces fruit that ripens earlier and is larger.
Blueberries have special soil requirements and will fail in alkaline and neutral soils, such as those of ordinary vegetable gardens. The ideal medium for them is a mixture of peat and sand, well drained and aerated but with an ample supply of water a foot or more below during the growing season. However in limestone regions and areas of alkaline and neutral soils, plants may be grown in pockets filled with a peat and sand mixture or one of 4 parts composted oak leaves (oak leaf mold) to 1 part sand. The pH of the soil has to be in the 4.5 to 5.5 range. No composted manure or alkaline fertilizers should be used. A fertilizer containing iron sulfate, ammonium sulfate or other acid fertilizer is recommended. Do not used fertilizers containing aluminum sulfate, which is often recommended for azaleas and rhododendrons, since the aluminum portion may be toxic to blueberry roots.
The roots of blueberry plants are fibrous and very fine, and they lack the vigor to penetrate heavy clay soils. More than 90 percent of the plant’s roots are usually in the top six inches of soil. Blueberries should be planted away from trees and shrubs since blueberries are poor competitors for water, sun, and nutrients. The plants need six to eight hours of sunlight a day.
Mulching with oak leaves, peat moss or sawdust will help keep the soil of the desired texture and acidity. The plants will bear fruit the first year, however top-quality fruit should begin to bear during the third year and by the fifth be in full bearing.