Some guidelines to grow great foxgloves, delphiniums and hollyhocks in your garden
Planting. Set out plants in well-drained soil amended with compost.
Fertilizing. To assure a robust flower spire, feed plants in late winter or early spring with a balanced dry fertilizer or a top dressing of well-rotted manure or compost.
Pruning. Cut the bloom stalks off delphiniums, foxgloves (Digitalis purpurea), and hollyhocks (Alcea rosea) as soon as they fade ― but well before they set mature seed. In most cases, plants will send up a new flower stalk later in the season.
Disease control. Most hollyhocks are prone to rust, a disease that produces orangy pustules on the undersides of leaves and spots on the leaf surfaces. It’s most severe in coastal areas when temperatures are between 64 and 70 degrees and moisture is present for several hours. At the first sign of rust, prune off damaged leaves and spray with sulfur mixed with horticultural oil.