In July and August, the attractive flowers of bee balm (Monarda) are a common sight in gardens, along roadsides, and in prairies. Bee balm attracts bees, butterflies, and hummingbirds. The common name of bee balm is in reference to its former use to treat bee stings. Other common names include bergamont, horsemint, and Oswego tea.
Three species of Monarda (Monarda didyma, Monarda fistulosa, and Monarda punctata) are native to Iowa. Numerous cultivated varieties are available at garden centers.
Bee balm flowers are borne atop the plants. The slender, tubular flowers are produced in 2- to 3-inch-wide flower heads. Flower colors include white, pink, red, lavender, and purple.
Bee balms are relatively easy to grow when given a favorable site and good care.
Bee balms perform best in moist, well-drained soils in full sun. The planting site should receive at least 6 hours of direct sun each day. Plants won't flower as heavily and are more susceptible to powdery mildew when grown in partial shade.
Bee balms like an even supply of moisture during the growing season. For best performance, water plants every 7 to 10 days during dry periods. When watering, soak the soil to a depth of 6 to 8 inches. Apply a mulch around plants to conserve soil moisture and reduce the frequency of watering.
Bee balms don't require frequent or heavy fertilizer applications. Sprinkling a small amount of an all-purpose garden fertilizer, such as 10-10-10, around each plant in early spring is usually sufficient. Avoid over fertilization. Frequent or heavy applications of fertilizer encourage rampant, succulent growth and may increase the severity of powdery mildew.
Promptly remove spent flower heads to prolong the bloom period of plants.
Bee balms spread rapidly via underground stems or rhizomes. In addition, the centers of the clumps often die out within a few years. To control their spread and rejuvenate plants, it's advisable to dig and divide bee balms every 2 to 3 years. Early spring is the best time to dig and divide bee balms. Dig up plants as soon as they emerge from the ground. Divide the clump into sections with a sharp knife. Each section should have at least 2 or 3 shoots and a good root system. Replant immediately.
Insect and Disease Problems
Bee balms may occasionally suffer some minor insect damage. However, powdery mildew is the most common problem. Powdery mildew is a fungal disease. It appears as a grayish white ‟powder" on the upper leaf surfaces. Severely infected leaves drop prematurely. Disease symptoms are most severe on overcrowded plants, those growing in partial to heavy shade, and drought stressed plants.
Cultural practices can reduce the severity of powdery mildew. When planting bee balms, select a site in full sun and space plants 2 feet apart. Divide plants every 2 to 3 years and water during dry periods. Remove and destroy disease-infested plant debris in fall. The fungal spores of powdery mildew survive the winter on disease-infested plant debris. The removal and destruction of this material removes the source of next year's infection.
The best way for home gardeners to avoid the annoying problem of powdery mildew is to select mildew resistant cultivars. Cultivars that possess good mildew resistance include 'Marshall's Delight' (bright pink flowers), 'Gardenview Scarlet' (scarlet-red flowers), 'Violet Queen' (violet-blue flowers), 'Raspberry Wine'(wine-red flowers), and 'Colrain Red' (purplish red flowers).
The native species and most older bee balm cultivars grow 2 to 4 feet tall. However, a number of dwarf cultivars have been introduced in recent years. 'Petite Wonder' (pink flowers) and 'Petite Delight' (rose pink flowers) grow 10 and 15 inches tall, respectively. 'Pardon My Pink' (pink flowers), 'Pardon My Lavender' (pinkish purple flowers), 'Pardon My Purple' (fuchsia-purple flowers), and 'Pardon My Cerise (pinkish red flowers) grow 10 to 12 inches tall. Intermediate-sized cultivars include 'Grand Parade' (lavender purple flowers, 13 to 16 inches tall), 'Grand Mum' (mauve pink flowers, 15 to 18 inches tall), and 'Grand Marshall' (fuchsia-purple flowers, 14 to 20 inches tall). All of the aforementioned dwarf cultivars possess good resistance to powdery mildew.
When sited properly and given good care, bee balm is a wonderful, easy-to-grow perennial for the home landscape.
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