Carex tumulicola is a fine-textured, clump-forming evergreen sedge native to oak woodlands and grassy slopes from British Columbia south through California. It is widely planted as a lawn substitute or low-maintenance groundcover in shaded Pacific Coast gardens, valued most for holding its form and color in dry shade where turfgrass fails.
Once established, foothill sedge requires little to no supplemental irrigation and no fertilizer. It spreads slowly by short rhizomes, forming a dense mat that suppresses weeds. Cutting the foliage back to 2–3 in above ground in late winter, before new growth begins, refreshes the planting without harming the crowns. It performs best in slightly acidic, well-drained soils under oaks, madrones, and other native canopy trees. Crown rot develops quickly in poorly drained or chronically wet sites, and plants set in heavy clay should be raised slightly on a berm.
Phytophthora Root Rot
Wilting despite moist soil, yellowing leaves, stunted growth, and dark, decayed roots and crown tissue. Vines may collapse during hot weather.
Plant in well-draining soil and avoid waterlogging. Remove and destroy affected vines. Improve drainage with raised beds or amended soil and avoid overwatering.
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.
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.