Heuchera citronelle is a cultivar of the popular and hardy heuchera perennial. These mound-forming perennials are desirable for their showy foliage and ability to grow in the shade. In addition, they are a favorite with home gardeners who have deer populations, as they are deer-resistant plants. Native to the United States, heucheras come in many shapes and colors, including purple, cream, silver, red, orange and variegated. The "Citronelle" cultivar features ruffled, lemon-colored leaves with silver undersides and tall, slender, cream-colored flowers.
Heuchera (sometimes called coral bells) in general are hardy in United States Department of Agriculture growing zones 4 through 9. Some cultivars are cold hardy to zone 3, and others are warm hardy to zone 11. Heuchera citronelle is hardy to USDA zone 4.
Plant heuchera citronelle in loamy soil that is rich in organic matter and very well-draining. Standing water will cause the plant to develop foot rot, which is when the roots of the plant rot away. Amend poor soil with organic mulch to improve the nutrient level, or peat moss and coarse sand to improve drainage.
Heucheras in general can grow in full sun, partial sunlight or full shade, depending on the cultivar and the home gardener's climate. Heuchera citronelle can grow in all three light conditions. In cooler climates such as zones 4 and 5, plant heuchera citronelle in full sunlight or partial shade. In warmer climates, plant it in partial shade or full shade. The colors will be more outstanding when planted in dense shade.
Keep the ground moist around your heuchera citronelle for optimum flowering. Water from below to avoid wetting the foliage, as leaf spot (a fungal disease that spreads on water) can develop on the yellow leaves of the heuchera citronelle cultivar. Add a 2-inch layer of mulch around the plant in the spring to stifle weed growth and keep the soil moist. Deadhead spent flowers (cut or pinch them off) to encourage new blooms to develop.
Heucheras are woody plants and can grow leggy. When this happens, the plant develops long stems with only a few leaves on top, giving them a bare rather than bushy appearance. Ciscoe Morris, a gardening expert who writes for the Seattle Times, suggests cutting the plants down very close to the ground in early March (to less than an inch tall).