With their 2- to 5-feet-tall spikes and their bell-shaped, 2- to 3-inch flowers that have spotted throats and range in color from yellow and white to pink or purple, common foxgloves (Digitalis purpurea) are easily identifiable in the garden. These European natives are deer- and rabbit-resistant and attract hummingbirds. Hardy in U.S. Department of Agriculture plant hardiness zones 4 through 8, foxgloves prefer well-drained soil in a sunny to partially shady area of the garden. With proper care, they grow oblong, light-green foliage in their first year and bloom the next year.
Water foxgloves immediately after planting them, thoroughly soaking the soil around the plants. Keep the soil somewhat wet initially, watering about three times during the first week. Provide 1 inch of water each week afterward, maintaining consistently moist, but not wet, soil and adjusting your watering frequency after rainfall. Water foxgloves in early morning, and avoid getting their leaves wet to prevent diseases.
Dig a 1-inch-deep trench in a 3-inch diameter around each foxglove plant. Sprinkle one handful of 5-10-5 granular fertilizer in each trench. Fill the trenches with soil, and water the soil. Do this in early spring and again six and 12 weeks afterward. Alternatively, apply a 1- to 2-inch-thick layer of compost around the foxgloves each spring to provide nutrients.
Spread a 2-inch-thick layer of organic mulch, such as shredded leaves or bark chips, on the soil around the foxgloves. Keep the mulch about 1 to 2 inches away from the plants. Mulch promotes soil moisture retention and keeps weeds at bay.
Treat and prevent powdery mildew outbreaks by properly spacing plants to allow proper air circulation, water from below and not overhead, clean up leaf debris below foxgloves and prune off affected foliage. Spray severe infections with ready-to-use Neem oil or horticultural oil, saturating the plant's foliage and repeating weekly or as needed. Do not use oil-based products when temperatures are above 90 degrees Fahrenheit or the plant is stressed from drought.
Remove slugs or snails from the foxglove's foliage in the early morning when the pests are most active. Wear gloves and pick the pest from the plant, placing them in a small bowl of soapy water. Prune off any foliage damaged by the snails or slugs.
Pinch off the foxgloves' wilted or faded flowers. Doing so keeps the plants looking neat and prevents them from spending energy on making seeds. Alternatively, wait until two-thirds of the flowers have faded, and then use pruning shears to cut back each entire stalk at the point where its base meets the bottom leaves.