My Misty plants are beautiful. I think a problem with one of my loved Mistys is partly(mostly) my fault. The berries all shriveled and some of the leaves have a red in them (a definite sign of stress).

Cold Stress From the 40°F Night (not my fault)

Misty is a Southern Highbush variety, and while it tolerates cool weather, young berries and tender new leaves are extremely sensitive to sudden temperature drops.

Cold exposure causes:

• Berries to stop sizing up

• Berries to shrivel or dry out

• Leaves to turn reddish or bronze (anthocyanin stress response)

• Slowed root activity

This matches your photos exactly.

Even though 40°F isn’t a freeze, rapid temperature swings can shock actively growing Southern Highbush plants.

2. Elemental Sulfur Can Temporarily Burn Roots

Elemental sulfur is excellent for lowering pH, but:

• It acidifies slowly, taking weeks to months

• If too much is applied at once, it can temporarily burn fine feeder roots

• Root burn → poor water uptake → shriveled berries

• Root stress also causes red or blotchy leaves

If the sulfur wasn’t mixed into the soil or was applied heavily on top, the risk is higher.

3. Fertilizer + Sulfur + Cold = Triple Stress

Fertilizing right after sulfur — especially if using ammonium sulfate or a strong nitrogen fertilizer — can:

• Spike soil salts

• Stress roots

• Cause leaf discoloration

• Reduce berry development

Blueberries have very shallow, sensitive roots, so timing matters.

4. Water Stress (Common in Containers)

Your photos show container plants, and container blueberries often experience:

• Drying out faster than expected

• Uneven moisture

• Root stress from heat or cold

When roots can’t supply enough water, the berries shrivel first, even if the leaves look mostly okay.

So What’s the Real Cause?

Based on everything:

✔️ Primary cause: Cold shock during active fruit development

✔️ Secondary cause: Root stress from sulfur + fertilizer

✔️ Contributing factor: Container moisture fluctuations

This combination is extremely common in early‑season Southern Highbush varieties like Misty.

What To Do Now

Here’s how to help the plant recover:

1. Keep soil evenly moist (not wet)

Blueberries hate drying out, especially after root stress.

2. Do NOT add more sulfur or fertilizer for 4–6 weeks

Let the roots recover.

3. Add 2–3 inches of pine bark mulch

This stabilizes moisture and protects roots.

4. Provide light shade during hot afternoons

Stressed roots + full sun = more shriveled fruit.

5. Remove severely shriveled berries

The plant will redirect energy to new growth.

6. Expect new leaves to look normal

The blotchy red leaves won’t turn green again, but new growth will be healthy.

Will the plant recover?

Yes — Misty is resilient, and this type of stress is temporary. You should see:

• New green leaves within 2–3 weeks

• Normal berry development next season

• No long‑term damage