Black-Eyed Susan Vine Declining: Drainage and Fertilizer Fixes

Reviving Thunbergia alata with Yellowing Leaves

Your vines bloomed well then declined—yellow leaves, few flowers despite fertilizer and watering adjustments. The culprit is likely poor drainage in clay soil, causing waterlogged roots that can't absorb nutrients.

Soil Amendment Plan

1. Work in organic matter: aged manure, peat, compost—2-3 inches deep over root zone.
2. Mulch with straw or shredded leaves to conserve moisture and cool soil.
3. Water deeply once weekly (1 inch), not 3x weekly shallow watering.

Fertilizer Correction

Use high-phosphorus, low-nitrogen fertilizer (e.g., 5-10-5) three times yearly: early spring, early summer, early fall. "Bloom booster" formulas work. Stop high-nitrogen feeds—they cause leafy growth without flowers.

Black-eyed Susan vines need well-drained soil and moderate fertility. Fix the soil, and they'll rebound.