Trifolium is a genus of legumes grown as a living mulch, cover crop, and pollinator forage. It fixes nitrogen through root nodules, improving soil for following crops, and its flowers feed bees and other insects. Gardeners use it to suppress weeds, hold soil, and reduce the need for added fertilizer.
Clover germinates fast and grows low and dense. Sow seed shallow on firmed soil and keep it moist until established. It tolerates mowing and foot traffic, regrowing from the crown. Cut or till it before or at flowering to return nitrogen to the soil. Perennial types persist several years; annual types are turned under each season.
Rust
Orange to brown raised pustules on the undersides of leaves, with yellow spotting on the upper surface. Heavy infections cause leaves to yellow and drop.
Remove and destroy infected leaves. Avoid overhead watering and improve air circulation. Apply a sulfur or copper-based fungicide if it spreads. Clear plant debris in fall.
Southern Anthracnose
Dark sunken lesions on stems and petioles, often girdling and blackening the crown; plants wilt and collapse in patches during warm, wet weather.
Plant resistant varieties, ensure good drainage, and avoid dense overcrowded stands. Remove infected plants and rotate to non-legume cover for a season.
Powdery mildew
White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Crown Rot
Lower leaves yellow and wilt; the base of the rosette turns brown and soft, sometimes with white fungal threads at the soil line. Plants collapse in wet conditions.
Remove and destroy affected plants. Improve drainage and avoid overhead watering. Do not mulch directly against the crown. Space plants for airflow and avoid replanting in the same wet spot.