Why are my blueberry leaves curling?

Blueberry leaves curl most commonly due to aphid infestation or blueberry tip borer damage. Aphids colonize the growing tips and undersides of young leaves, causing the new leaves to curl tightly around the colony; the curled, puckered new growth with insects visible is distinctive. Blueberry tip borer (Hendecaneura shawiana) larvae tunnel into the growing tips, causing the tip leaves to curl and wilt without visible insects on the outside; inspecting inside a curled tip may reveal a tiny larva. Drought stress causes the leaves to curl upward and the plant to look stressed, particularly in containers; blueberries need consistent moisture and are sensitive to periods of drought. Soil pH that is too high prevents blueberries from absorbing iron and other nutrients, causing yellowing between the veins (iron chlorosis) and reduced vigor alongside curling. Blueberry scorch virus and blueberry shock virus cause rapid browning and distortion of flowers and new leaves in spring.

Why are my blueberry leaves curling and turning red?

Blueberry leaves curling and turning red, particularly in spring or early summer, most commonly indicate drought stress, nutrient deficiency, or the normal stress response of the plant in difficult conditions. Blueberries naturally display red foliage in autumn as they prepare for dormancy, but premature reddening in spring or summer alongside curling suggests physiological stress. Drought causes the leaves to redden and curl as the plant's metabolism is disrupted. Phosphorus deficiency causes reddening of leaf margins and undersides, sometimes with curling. Soil pH that is too high (above 5.5 to 6.0) prevents uptake of multiple nutrients, causing a combination of yellowing, reddening, and poor growth. Check soil pH with a test kit; blueberries need pH 4.5 to 5.5 to thrive and absorb nutrients properly.

What soil pH do blueberries need?

Blueberries require acidic soil with a pH between 4.5 and 5.5 to grow and fruit well. This is significantly more acidic than the pH range most garden plants prefer, and most garden soils are too alkaline for blueberries without amendment. In soil with pH above 5.5 to 6.0, blueberries cannot absorb iron, manganese, and other micronutrients, leading to iron chlorosis (yellowing between the veins), poor growth, leaf curl, and eventually decline regardless of watering and feeding. Lower soil pH by incorporating sulfur into the planting hole well before planting (sulfur takes months to acidify soil), using acidifying fertilizers such as ammonium sulfate, mulching with pine bark or wood chips, and watering with rainwater rather than alkaline tap water. Test soil pH annually in spring to monitor and maintain the target range.

Blueberry Leaves Curling — Why It Happens and How to Fix It

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At a glance

New growth tightly curled with insects visible: Aphids; treat with insecticidal soap
Growing tips wilting and curled with no visible insects: Blueberry tip borer; prune out infested tips
Leaves curling upward with dry soil: Drought; water consistently and mulch heavily
Leaves yellowing between veins with stunted growth: Iron chlorosis from high soil pH; acidify soil and apply chelated iron
Leaves distorted with browning flowers in spring: Blueberry virus; remove infected plant

Why blueberry leaves curl

Blueberries (Vaccinium corymbosum and related species) are long-lived fruiting shrubs that, when grown in the right conditions, can produce fruit for decades. The right conditions are specific: they need very acidic soil (pH 4.5 to 5.5), excellent drainage, consistent moisture, and full sun. When any of these conditions are off, the plant shows it quickly in its foliage. Blueberry leaves curl in response to pest attack, drought, and the nutritional consequences of wrong soil pH. Knowing that blueberries are among the most pH-sensitive common garden plants is essential background for any diagnosis: many problems that look like pests or watering issues are actually downstream effects of wrong soil chemistry.

Cause 1: Aphids

Signs: The new growth at the tips of branches is tightly curled and distorted. Small soft-bodied insects are visible on the undersides of the curled leaves and inside the curled growing tips. Sticky honeydew residue may be present on lower leaves. Ants are climbing the branches. The damage is confined to the newest tissue at branch tips.

Why it happens: Several aphid species attack blueberries, including the blueberry aphid (Ericaphis fimbriata) and the blueberry-colonizing forms of other aphids. They concentrate on the tender new growth at branch tips and feed on sap, injecting saliva that causes the young leaves to curl tightly around the colony, sheltering it from both predators and contact sprays. Blueberry aphids also transmit blueberry scorch virus and blueberry shock virus.

Fix: Apply insecticidal soap or neem oil directly to the curled growth, ensuring the spray reaches inside the curled leaves where the aphids shelter. A forceful blast of water first helps dislodge aphids from the curled tissue. Repeat every 5 to 7 days for 2 to 3 applications. On fruiting plants near harvest, use products labeled as safe for edible crops and observe the required pre-harvest interval. Avoid systemic insecticides during flowering, as these harm pollinators essential for fruit set.

Cause 2: Blueberry tip borer

Signs: The very tips of some branches are wilting, curling, and dying back. The wilted tip leaves may be rolled tightly. No insects are visible on the outside of the affected tip. Cutting open an affected tip reveals a small larva or larval tunnel inside the tissue. The damage appears in spring to early summer. Individual tips are affected rather than the whole plant.

Why it happens: The blueberry tip borer (Hendecaneura shawiana) is a small moth whose larvae hatch and bore into the growing tips of blueberry branches, tunneling through the tip tissue and disrupting water flow to the tip leaves. The result is a wilted, curled, dying tip that looks from the outside like drought damage but does not respond to watering. The damage is unsightly but typically does not threaten the whole plant, as established blueberries produce new growth from lower buds.

Fix: Prune out affected tips promptly, cutting a few inches below the visible damage into healthy tissue. Dispose of the pruned material; do not compost it, as it contains living larvae. Disinfect pruning tools between cuts with rubbing alcohol. In subsequent seasons, applications of spinosad in spring when the moth is laying eggs can reduce larval establishment.

Cause 3: Drought stress

Signs: The leaves are curling upward and the plant looks stressed, particularly during dry or hot periods. The soil is dry beneath the mulch. Container blueberries are especially affected. The symptoms appeared during a dry spell or after a gap in watering. Established leaves may also show browning at the tips and margins.

Why it happens: Blueberries have a fine, shallow root system that does not penetrate deeply into the soil. They need consistent moisture throughout the growing season and are particularly sensitive to drought during fruit development, when water stress reduces fruit size and quality. Container blueberries in warm weather can dry out within a day or two.

Fix: Water deeply and consistently, keeping the soil evenly moist. Apply a thick layer of acidic organic mulch (pine bark, wood chips, or pine needles) around the base to retain moisture and maintain soil acidity. Container blueberries may need watering daily in peak summer. Using rainwater or pH-adjusted water rather than alkaline tap water maintains soil acidity over time.

Cause 4: Iron chlorosis from high soil pH

Signs: The leaves are turning yellow between the veins while the veins themselves remain green. The yellowing is most pronounced on the youngest leaves. Growth is slow and the plant is not producing well. The soil may have been amended with lime, or the site receives alkaline tap water or is in naturally alkaline ground.

Why it happens: Blueberries require pH 4.5 to 5.5 to absorb iron and other micronutrients. In soil above pH 6.0, iron is present but chemically unavailable, causing iron chlorosis. This is one of the most common and serious problems for blueberries planted in typical garden soil or near concrete foundations that raise local pH.

Fix: Apply chelated iron as a foliar spray and soil drench for rapid improvement. Lower soil pH long-term by incorporating elemental sulfur (applied months in advance to allow time to work), using ammonium sulfate as the primary fertilizer, and mulching with pine bark or wood chips. Test soil pH annually and target 4.5 to 5.0 for best results. Avoid using alkaline water and do not lime areas near blueberries.

Cause 5: Viral infections

Signs: Leaves and flowers are rapidly browning, distorting, and dying back in spring. The browning appears first on flowers and then spreads to new leaves, giving the plant a scorched appearance. The plant may partially recover but performs poorly in subsequent years. The damage appeared suddenly across multiple branches or the whole plant at once.

Why it happens: Blueberry scorch virus (BlScV) and blueberry shock virus (BlShV) are serious viral diseases spread by aphids (scorch) or pollen and bees (shock). Both cause dramatic spring symptoms that can look like frost damage. Infected plants may appear to partially recover but remain infected and perform poorly long-term, and remain a source of virus for nearby healthy plants.

What to do: Consult your local agricultural extension service to confirm the specific virus. Remove and destroy severely infected plants. Control aphids on remaining plants to reduce scorch virus spread. Blueberry shock virus, spread by bees, is harder to control; removing infected plants is the primary management strategy. Purchase certified virus-free planting stock when replanting.

Blueberry Leaves Curling