Goldenrods: Falsely Accused?

Goldenrods are one of the most maligned, misunderstood, and unappreciated groups of our native plants. In Europe, where there is only a single native common species,Solidago virgaurea, horticulturists have developed many varieties for enthusiastic gardeners. Many of our native species were introduced into Europe during the 1700s, where some have naturalized and are considered invasive. In the U. S., there are approximately 95 species of the goldenrod genera Solidago and Euthamia (the flat-topped goldenrods). In Virginia, there are 38 species reported in the Digital Atlas of the Flora of Virginia, twenty of the species are reported in our area. Goldenrods, with the exception of “Silver rod” (Solidago bicolor), which has almost white flowers, have flowers of a golden yellow color. The genus name Solidago means “to make whole,” reflecting the centuries-old belief in the healing wounds property of various species. One of the classic names for goldenrods is “woundwort.” The genus name Euthamia connotes “well-crowded,” referring to the dense arrangement of flowers on the flat-topped inflorescences.

Goldenrods, as members of the composite family (Asteraceae), have relatively small flower heads (capitula) of both ray flowers (which have pistillate or female only) and disk flowers (with both staminate (male) and pistil) borne in groups on flowering stems called inflorescences. Ray and disc flowers develop from a base or receptacle that is enclosed beneath the receptacle with an involucre, a cup of leafy bracts (phyllaries) or modified leaves. The five petals of both ray and disc flowers are fused together. The sepals are modified into pappi, which are straight hairs that may have small barbs. The fruits are dry: fruits called cypselae that are cone to cylindrical in shape. The pappi are attached to the upper end of the fruits that assist in wind dispersal. The inflorescences are typically club, wand, plume-shaped, or elm-branched shaped. The leaves are always alternate with parallel or netted veins depending on the species. The shape of the inflorescence, as well as leaf shapes and venation patterns, are used to identify species. Even expert botanists sometimes have difficulty in identifying individual species since species often hybridize. All species are perennials and many have rhizomes.

Goldenrods have an undeserved notoriety for causing allergies. Their pollen grains are relatively large, heavier than air, because they are designed to be carried off by flies, bees, and butterflies, but not by the wind. Wind-pollinated plants usually have un-showy flowers and very light weight pollen in extreme abundance. It is the wind-pollinated plants such as ragweed, grasses, sedges, wormwoods, oaks, pines, and many other large trees that cause hay fever. The ecological relationships between goldenrods and animals are fascinating as pollen and nectar sources for insects, stem and leaf tissue eaten by insects and other animals, and the stem tissue as sites for certain insects to lay eggs to develop inside swollen stem tissue that form galls.

The leaves of some goldenrod species have been dried and used as teas or infusions to treat urinary tract problems such as kidney stones and as a diuretic. Various preparations have been used as an anti-inflammatory agent, as an astringent as well as to soothe skin problems, and to stop hemorrhaging. Sweet goldenrod (S. odora), a species found in western part of our area, is used as a popular, slightly anise-flavored tea.   Called “Liberty Tea” in American Revolutionary times, it was used to replace the heavily taxed British tea. Another popular goldenrod tea is “Blue Mountain Time,” used as a pick-me-up. It is claimed that these teas can be used to treat hay fever, sore throats, coughs, and colds. Leaves of some species can be cooked and eaten as greens. Other uses of goldenrod include the dried inflorescences in fall flower arrangements, as a dye source (especially from gray goldenrod, S. nemoralis), and as handsome additions to wild and cultivated gardens. Thomas Edison even tried to extract rubber from goldenrod plants to replace rubber from foreign countries during times of war but this never was a commercial success. Some web sources are listed at the end of this article that will give you more information on these uses.

As you enjoy the last displays of late-summer and early-autumn color, try to appreciate the variety and beauty of goldenrods. Let’s clear the name of this lovely genus that can add so much color to the late season flowering landscape or to your own wildflower garden.

Below are some suggested sites for further reading:

Medicinal uses:

http://www.unm.edu/altmed/articles/goldenrod-000251.htm

“How the Ancients Used the Plants, with Special Focus on Native American Herbal Medicine & How to Use Them Today,” in Goldenrod Ethnobotany: Solidago of the Upper Delaware (Wayne County, PA and adjacent counties) by Nathaniel Whitmore

Use as dyes:

“Goldenrod Dye,” author unknown.

“5  Orange Potatoes,” by Lisa Crinklebein

Edible uses:

“Goldenrod (Solidago) ~ LuminEarth’s Guide to Wild Edible & Medicinal Plants,” by Becky Baumgartner

Edison’s extraction of rubber from goldenrod:

“Thomas Edison, Rubber from Goldenrod,” by Vincent Summers