University of California
UC Master Gardener Program of Sonoma County
Most gardeners plant blueberries to reap the rewards of the delicious fruits, but they are often planted as an ornamental for the benefit of their attractive foliage and shrubby form. Blueberry bushes will grow in nearly any area regardless of the intensity of the sun if adequate cultural methods are adhered to, including soil acidity, sufficient water, and a protective mulch over the root zone.
Soil is Key
- Blueberries thrive only when planted in very acidic soil with a pH of 5.6 or lower.
- Adding an acid-reacting fertilizer to soil creates a hospitable environment for blueberries.
- To prepare acidic soil conditions, mix in copious amounts of an acidic material such as nitrolized sawdust or some other high acid wood product. This is best done at least a year before any plants are purchased as it takes quite a bit of time for the wood to break down.
- Nitrogen deficiency will occur in soil when raw sawdust or other wood product is used. If microorganisms convert the carbon content into compost without added nitrogen, they deplete the soil of nutrients needed by plants.
- Blood meal is one of the fastest acting, acid-reacting organic fertilizers. Alfalfa meal, composted manure, and compost are also useful.
Planting and Ongoing Care
- Blueberries require cross-pollination to set fruit. Bees need to visit 2 different varieties planted near each other that bloom at the same time.
- Blueberries are shallow-rooted and need a protective layer of mulch to hold in soil moisture, guard against temperature extremes, and retard weed growth.
- After planting, mulch the entire root area with 6-in. of shredded bark or nitrolized sawdust.
- Hand weed carefully to avoid injuring the main feeder roots found near the surface.
- Plants require about 1 in. of water a week; roots should never be allowed to dry
- Water-in annual applications of ammonium sulfate at the rate of 1/2 pound per plant or use an equivalent organic product. Apply half doses in mid-February and late April to correlate with bloom time and fruit set.
- Every third year, fertilize with a complete fertilizer such as 5-10-10, carefully working it into the root zone but away from the base of each shrub.
- Little or no pruning should be done the first 2-3 years except to remove flower clusters which allows the plant to build strength.
- In subsequent years, in the dormant season, remove weak growth to a strong lateral or entirely to the base; take out old canes when the plant needs thinning.
- Once fruit begins to turn blue, cover shrubs with bird netting.
- A simple scaffold can be made of PVC tubing with netting placed over it and anchored to the soil, covering all parts of the plant to exclude birds. Birds are able to find even slight openings.
- With good care throughout the year, blueberries remain disease-free.