Corsican mint is the smallest and most intensely fragrant of all mints — a moss-like ground cover barely an inch tall that releases a powerful pennyroyal-peppermint scent when stepped on. It is ideal between stepping stones, in rock gardens, and in containers where its low mat can spill over edges. Unlike most mints it prefers partial shade and consistent moisture.
Hardy to Zone 6a but can struggle in hard winters — a light layer of pine straw gives enough protection in Zone 6b. Does not tolerate foot traffic as well as creeping thyme.
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.
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.
Slug and Snail Damage
Deroceras reticulatum →Large irregular holes chewed in leaves, with slime trails on foliage and soil.
Hand-pick at night, set beer traps, or apply iron phosphate bait. Remove debris and mulch where they hide.