Learn About Blueberries

Posted in: Blueberries
Learn About Blueberries

How To Sow    How To Grow    Tips    Common Pests    FAQ

How to Plant

  • Blueberries may be planted as bare root or potted plants.
  • Blueberries thrive in a sunny to partially shaded location, in well drained, very acidic soil, with a pH of 4.2-5.2. If your pH is higher, add garden sulfur according to package directions. Do not change the pH of your soil more than ½ of a point each year.
  • Plant at least two varieties that bloom at the same time for cross pollination and better yield.
  • Set plants 4-8 feet apart (3 feet apart for hedges). Dwarf varieties may be planted in containers.

Planting Bare Root Plants:

  • Dig each hole twice the size of the root mass.
  • Keep the crowns above the soil level. Plant into the hole and back fill with loose soil. Gently press soil in around the root ball. Transplants need good root-to-soil contact. Do not press too hard because that can cause soil compaction and root damage.
  • Gently water around the root ball to settle the soil and drive out air pockets.
  • After planting be sure to mark the plants with plant labels so you know where they are and what varieties they are.
  • Mulch with 2-3 inches of compost of pine needles to retain moisture and prohibit weed growth.

Planting Potted Plants:

  • Set the plant in the hole at the same depth as it was growing in the pot.
  • Backfill the hole and press firmly around the base of the planting.
  • Water deeply. The water will seal off any air pockets around the root ball.
  • After planting be sure to mark the plants with plant labels so you know where they are and what varieties they are.
  • Mulch with 2-3 inches of compost of pine needles to retain moisture and prohibit weed growth.

How to Grow

  • Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients. Control them by either cultivating often or use a mulch to prevent their seeds from germinating.
  • Keep plants well-watered during the growing season, especially during dry spells. Plants need about 1-2 inches of rain per week during the growing season. It's best to water with a drip or trickle system that delivers water at low pressure at the soil level. If you water with overhead sprinklers, water early in the day so the foliage has time to dry off before evening, to minimize disease problems. Keep the soil moist but not saturated.
  • Do not fertilize newly planted bushes until they have leafed out. Work a fertilizer designed for acid-loving plants into the top 3 inches of soil around each plant. Apply again 4-6 weeks later. After the first year, fertilize in spring as new growth begins, and again 4-6 weeks later. Apply fertilizer to the soil beneath each bush, keeping it 5-6 inches away from the main stem.
  • Remove flowers the first year to strengthen plants.
  • Prune in late winter or early spring while the bushes are dormant. The first three years, remove small lateral shoots and thin out excessive bushy growth. After the third year, annually remove 1/4 - 1/3 of the old wood, any dead or injured branches, and those close to the ground.
  • Monitor for pests and diseases. Blueberries are remarkably disease resistant. Check with your local Cooperative Extension Service for pest controls recommended for your area.
  • Pick fruit promptly to discourage insects.
  • Do not water as frequently after early September unless the soil is very dry.
  • Mulch after the ground freezes in fall to prevent root damage from alternating freezing and thawing.

Harvest and Preserving Tips

  • Cover bushes with bird netting as fruit ripens. Netting should not touch blueberries.
  • Blueberry fruits turn blue before they are fully ripe. The acid level will continue to fall for three to seven days after the fruit turns blue. The underside of the berry will turn from pink to full blue when it is fully ripe.
  • Harvest only when the weather is dry and avoid over handling to preserve the whitish, waxy surface of the berry, which protects it from fruit molds.
  • Pick promptly to avoid insects.
  • Harvest the berries only.
  • Cool fruit promptly after harvesting and store between 32 - 40 degrees F.
  • Blueberries freeze well for later use. Freeze them in a single layer on a cookie sheet, and when they are frozen you can keep them frozen in zip lock bags.

Common Disease Problems

Alternaria Leaf Spot: This can occur in cool, wet spring weather, mostly on the lower leaves. Brown or gray lesions are irregular in shape, and are surrounded by a red border. Severe cases can lead to defoliation and damaged fruit post harvest. Burpee Recommends: Avoid getting water on the foliage when watering and remove affected leaves.

Mummy Berry: This causes rapid wilting or leaves, flowers and twigs and causes developing fruit to be deformed. Infected fruit can turn gray by midsummer and fall to the ground where the spores of the fungus can overwinter. Burpee Recommends: Remove infected fruit before it falls to the ground, or bury them deeper than 1 inch by cultivating around the plants before leaf drop in fall. Remove infected plant material. Control weeds. Contact your Cooperative Extension Service for fungicide recommendations.

Phytophthora Root Rot: This soil borne disease thrives in poorly drained soils and can live in the soil for years. Above ground symptoms include pale or reddish leaves, small leaves, defoliation, branch die back, stunting and death. Burpee Recommends: Remove infected plants and do not plant in that area in the future.

Powdery Mildew occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.

Stem Cankers and Twig Blights: Stem canker symptoms include lesions on stems that develop into cankers and deep cracks. They can girdle the stem in a few years and eventually kill the plant. Burpee Recommends: Prune out infected tissue and sterilize your pruners before using them on healthy tissue. 

Common Pest and Cultural Problems

Aphids: Greenish, red, black or peach colored sucking insects that can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.

Blueberry Maggot: This insect can affect fruit. The female fly lays eggs on the fruit and the larvae burrow into the berry. Burpee Recommends: To avoid this pest harvest the fruit as soon as possible when it is ripe. Yellow sticky traps can catch the females before they lay their eggs.

Discolored Foliage: Brown foliage can result from drought stress, particularly in mid-summer. Burpee Recommends: Water regularly and use mulch to conserve water and control weeds. Red or purple foliage could simply be the fall color as blueberries turn red in the fall. Sometimes this occurs in cold weather as well.

General Poor Growth: An acid soil is essential for good growth of blueberries. When the soil pH is over 5.2 plants can develop an iron deficiency and when the pH is below 4.2 they can suffer from manganese toxicity. If your pH is more than a half point from the recommended range of 4.2 - 5.2, consider growing blueberries in containers. It is not safe for the soil to change the pH more than half a point per year. Burpee Recommends: If your soil is within range but needs to be adjusted, use garden sulfur, peat moss or pine compost to lower pH; use lime or epsom salts to raise it.

Plum Curculio: Small, 1/4 inch long mottled greyish weevils with long snouts feed on the flowers and young fruit. The female lays eggs on the fruit and the larvae burrow into the fruit. They are nocturnal but may be found in the early morning. Burpee Recommends: Contact your Cooperative Extension Service for control assistance.

Blueberry FAQs

When will I get fruit? You should begin to get berries the second year after planting. If your plants bloom the first year, it is best to remove the flowers to keep the strength in the plant.

Do I need to do something special to grow blueberries?  Blueberry plants require an acidic, moist but well drained soil, they are native to sandy pine barrens with high water tables. Improve the drainage of your soil by adding generous amounts of compost and peat moss to the planting area prior to planting. Test the soil pH to make sure it is within the preferred range of 4.2-5.2. Consider planting in containers if your soil is too far outside the preferred pH range.

Are there seedless blueberries?  No, there are no seedless blueberries, but the seeds are small and not usually noticeable.

Do I have to grow the container varieties in a container?  No, just remember they will only grow 2-3' tall when you plan your garden.

What does "early", "mid", and "late" season mean, and how does it affect the best choice for a cross pollinator?  Blueberries are harvested between June and August. Some varieties ripen in June and are considered "early", some in July ("mid), and some in August ("late"). When choosing varieties for cross pollinating choose varieties that produce around the same time.

May 10, 2021
©2023 W.Atlee Burpee & Co