Knockout Rose Petals Browning at Edges: Midge, Fertilizer Burn, or Water Stress?

In Plano, TX (Zone 8), a mature Knockout blooms well but petals brown at edges after April trim. Gardener asks if fertilizer needed.

Three Main Causes

1. Rose Midge: Tiny larvae in buds → brown edges, deformed flowers. Test: Tear open a bud—look for tiny white worms.
2. Fertilizer Tip Burn: Excess fertilizer + heat → petal edges scorch.
3. Water Stress: In high heat, roses need ~5 gallons every 5 days (1 large bucket).

Step-by-Step Diagnosis

1. Check buds for midge larvae. If found: spray midge-labeled insecticide + drench soil base.
2. If no larvae: Deep-water daily for a week to flush fertilizer salts and hydrate fully.
3. Adjust watering: 5 gallons/5 days in 90°F+ heat. Mulch heavily.

Don't fertilize now—heat + chemicals = more burn. Fix water/midge first.