Hollyhocks (Alcea rosea) have graced gardens around the world for centuries. The biennial or short-lived perennial offers ease of growth and of care. Available in dwarf varieties or standards, the plants range from 2 feet to over 9 feet in height. Flowers appear on the plant during the second year of life. Single or double blossoms of white, red, pink and dark burgundy bloom during the hot summer months when many other plants have ceased to produce abundant flowers. The plants offer hardiness in Zones 3 to 8. Hollyhocks establish and propagate with ease from seeds.
Plant seeds in a location that offers full sunlight or partial sun. The soil should be well-draining with no standing water. Mix organic matter into the soil such as peat moss, leaf debris or aged manure. The soil should appear and feel crumbly to the touch. Choose a location that offers moderate wind protection for tall hollyhock varieties. If winds are a problem in the area, the taller hollyhocks may need staking.
Sow seeds 1/4-inch deep in the soil one week prior to the last frost. Lightly cover the seeds with soil. Germination begins 10 to 14 days after planting.
Thin hollyhock seedlings 18 to 36 inches apart. Seedlings can also be transplanted to various planting locations in the garden once germination occurs instead of discarding the young plants.
Water the young hollyhock plants abundantly to keep the soil moist in hot weather. The soil should feel moist to the touch but not overly damp. Avoid watering hollyhocks using overhead sprinklers because the plants are prone to rust and fungal infections. The heavy weight of the water on the hollyhocks flowers will often bend them over, too. Water using a soaker hose or drip irrigation system.
Fertilize the hollyhocks once per month in the summer using a water soluble general purpose fertlizer such as 10-10-10. Apply according to the directions on the label.
Apply copper- or sulfur-based fungicides if the plants show signs of powdery mildew or rust. Powdery mildew makes the plant's leaves appear to be coated in a fine powder and rust appears as rust spots on the underside of the plants foliage. Apply fungicides according to the directions on the label.