Monarda

Description

Monarda species include annual and perennial herbaceous plants. They grow erect to heights of 20–90 cm (8–35 in). The slender, serrated, lanceolate leaves are oppositely arranged on the stem, hairless or sparsely hairy, and about 7 to 14 centimeters long.

The flowers are tubular and bilaterally symmetric, with a narrow upper lip and a wider lower lip. The wild flowers are single, but some cultivated forms have double flowers. They are hermaphroditic, with male and female structures in each flower. There are two stamens. Inflorescences occur at the top of the stem or emerge from the axils. They are typically crowded head-like clusters of flowers with leafy bracts. Flower color varies, with wild species bearing red, pink, and light purple flowers. M. didyma has bright carmine red flowers, M. fistulosa has pink, and M. citriodora and M. pectinata have pale purple. Hybrids occur in the wild, and they are common in cultivation. Seed collected from hybrids does not yield plants identical to the parent.

Uses

The crushed leaves of all species exude a spicy, fragrant essential oil. Of the species examined in one study, M. didyma contained the highest concentration of oil.

Several species, including Monarda fistulosa and M. didyma, have a long history of use as medicinal plants by many Native Americans, such as the Blackfoot, Menominee, Ojibwa and Winnebago. The Blackfoot recognized the strong antiseptic action of the plants, and used them in poultices for skin infections and minor wounds. Native Americans and later settlers also used it to alleviate stomach and bronchial ailments. A tisane made from the plant was also used to treat mouth and throat infections caused by dental caries and gingivitis. Bee balm is a natural source of the antiseptic compound thymol, the primary active ingredient in some modern commercial mouthwash formulas. The Winnebago used a bee balm tisane as a general stimulant. Bee balm was also used as a carminative herb by Native Americans to prevent excessive flatulence. An infusion of crushed, boiled Monarda has been used to treat headache and fever.

Although somewhat bitter due to the thymol content in the leaves and buds, the plant tastes like a mix of spearmint and peppermint with oregano. Bee balm was traditionally used by Native Americans as a seasoning for wild game, particularly birds. The plants are widespread across North America and can be found in moist meadows, hillsides, and forest clearings up to 5,000 feet (1,500 m) in elevation.

Cultivation

Monarda plants thrive in sun and moist but well-drained soil. Plants growing in partial shade spread horizontally and produce fewer flowers. Monarda are used in beds and borders to attract hummingbirds, pollinating insects, and insects that control garden pests.

There are over 50 commercial cultivars whose hybrid colors range from dark red mahogany to bluish lilac to multiple shades of pink. These are generally not as robust as wild species. Some hybrids have been developed to produce high levels of essential oil for use as flavoring or medicine.

The following cultivars have gained the Royal Horticultural Society's Award of Garden Merit:

Ecology

Monarda species are used as food plants by the larvae of some Lepidoptera species, including case-bearers of the genus Coleophora. Coleophora monardae feeds only on Monarda plants, and C. heinrichella and C. monardella only feed on the species M. fistulosa.

Taxonomy

Monarda is in the tribe Mentheae of the subfamily Nepetoideae in the mint family. Molecular phylogenetic studies of this tribe have been poorly sampled, and relationships within it remain unclear. The genera Blephilia and Pycnanthemum are close relatives of Monarda, but they might not be the closest. Monarda is divided into two distinct subgenera, Monarda and Cheilyctis. These are easily distinguished by several characters.

1. Monarda bartlettii Standl. - Tamaulipas, Veracuz
2. Monarda bradburiana L.C.Beck – eastern beebalm - mid Mississippi Valley
3. Monarda citriodora Cerv. ex Lag. – lemon beebalm, lemon-mint - southern United States, northern Mexico
4. Monarda clinopodia L. – white bergamot, basil beebalm - eastern United States, especially Appalachians
5. Monarda clinopodioides A.Gray – basil beebalm - Kansas, Oklahoma, Texas, Louisiana
6. Monarda didyma L. – Oswego tea, scarlet beebalm, fragrantbalm, mountain-mint - eastern United States, especially Appalachians, eastern Canada
7. Monarda eplingiana Standl. - Coahuila
8. Monarda fistulosa L. – wild bergamot, mintleaf beebalm, horse-mint, purple beebalm - widespread across most of United States + Canada; Tamaulipas, Nuevo León; cultivated in China and elsewhere
9. Monarda fruticulosa Epling – spotted beebalm - southern Texas
10. Monarda humilis (Torr.) Prather & J.A.Keith - New Mexico
11. Monarda lindheimeri Engelm. & A.Gray ex A.Gray – Lindheimer's beebalm - Texas, Louisiana, southwestern Arkansas
12. Monarda luteola Singhurst & W.C.Holmes - northeastern Texas, southwestern Arkansas
13. Monarda maritima (Cory) Correll – seaside beebalm - coastal plain of Texas
14. Monarda media Willd. – purple bergamot - Ontario, eastern United States
15. Monarda × medioides W.H.Duncan - Georgia, Indiana (M. fistulosa × M. media)
16. Monarda pectinata Nutt. – plains beebalm, pony beebalm, spotted beebalm - central + southwestern United States (Great Plains, Rocky Mountains, southwestern desert mountains)
17. Monarda pringlei Fernald - Nuevo León
18. Monarda punctata L. – spotted beebalm, dotted monarda, horse-mint - Quebec, Ontario, eastern + south-central United States, California, northeastern Mexico
19. Monarda russeliana Nutt. ex Sims – redpurple beebalm - Texas, Oklahoma, Arkansas, Alabama, Mississippi, Kentucky
20. Monarda stanfieldii Small – Stanfield's beebalm - central Texas
21. Monarda viridissima Correll – green beebalm - east-central Texas

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