As with all berries and fruits, blueberries will continue producing their best if they are maintenance pruned.
The first 2 years, all you really need to do is remove any flowers that appear. I know that’s hard to do, but it will pay big dividends in the long run. Your plants will get bigger and more vigorous because of this. Berries are produced on branches in their 2nd year of growth, so it’s important to be constantly renewing the blueberry bush.
You can leave the flowers on for the third year. You won’t get many berries, but no pruning is necessary until the 4th year.
Beginning in the 4th year, you’ll prune your blueberry bushes in early spring, while they are still dormant. Prune out any:
- Dead or injured branches
- Crossing Branches
- Weak, spindly branches
What you really want to accomplish is to open the bush up so that light can reach the berries in the middle of the bush. You don’t need to be too drastic.
Maintenance pruning in subsequent years will amount to thinning out the older branches to encourage new growth. Cut back the oldest, thickest branches to near ground level and prune back branches that have gotten to long or that are growing too thin. Older branches will look gray. Newer branches will have more of a reddish tinge.
Berries form on the fruiting spurs of side branches. The flower buds will be larger, plumper and rounder than the pointed leaf buds.
Pests and Diseases
Birds: By far the biggest problem growing blueberries is keeping the birds away. With only a few bushes, you can use bird netting as the berries start to ripen. Some gardeners encase their whole blueberry rowing area in a netted cage. If you have a large blueberry garden, you should consider using a bird deterrent that sends out a bird in distress call. It actually keeps birds out of the area.
Insects: Insects to on the lookout for include blueberry tip borer, cherry fruitworm, cranberry fruit worm and plum curculio. If these are common pests in your area, check with your local extension for the prescribed deterrents and treatments.
Diseases: There are a number of fungal disease that can affect blueberries, including powdery mildew and leaf spot diseases. Your best defense is to plant resistant varieties, give your plants plenty of space for good air circulation, plant in full sun and clean up any fallen debris and replace the mulch annually, so the spores cannot over-winter in the area. If you should experience problems, you may need to use a fungicide labeled for use on edible plants.
Some other common blueberry diseases to keep an eye out for:
- Anthracnose: A fungal disease that spreads rapidly in damp weather. Symptoms are bright pink clusters of spores on the developing berries.
- Botrytis: Another fungus that thrives in damp conditions, botrytis will cause the fruit to shrivel and rot.
- Canker: Fusicoccom (Godronia): This disease begins on the lower parts of the canes. You’ll notice small reddish spots that will enlarge into a bullseye. If left untreated, they will eventually circle and gridle the cane, causing it to die-back.
- Mummy Berry: This is one of the more serious diseases to affect blueberries. Mummy berry is caused by a fungus. The first signs of infestation are blackening of the flower clusters, which eventually die. Because it is a fungus, the spores can linger and infect remaining blossoms. The resulting fruit turns tan and hard, looking like mummified berries.
- Twig Blights. (Phomopsis): Twig blight can start off looking very similar to canker. As twig blight progresses, it can also affect the crown, smaller branches and twigs as well causing leaf spotting.
Chlorosis (Yellowing Leaves): It’s not uncommon for blueberry leaves to begin to yellow or look chlorotic. Although this is usually a sign of iron deficiency, it is probably not caused by a lack of iron in the soil. More likely it is telling you that the soil pH is too high and the blueberry plants cannot access the iron that is already there. If you see yellowing progressing, have your soil pH tested and make adjustments.