August 2023: Goldenrods (with asters to follow in September)
This is the first of a two-part series on these important native plant partners. This month we will talk about goldenrods and, in September, asters. Both typically bloom during this season of shining light and dramatic contrasts.
Homegrown Habitat author Sarah Middeleer, a landscape designer, notes that goldenrods are reputed to cause hay fever, but the true culprit is ragweed, which blooms at the same time. Goldenrod produces sticky pollen, requiring insects to extract and spread it for pollination. Ragweed, on the other hand, is wind pollinated—to the great discomfort of many humans.
Questions or comments? Write to Sarah at firstname.lastname@example.org.
The dynamic duo of yellow goldenrods and purple asters is one of the glories of the late-summer landscape. These members of the aster family often grow near one another, for good reason – bees, who benefit greatly from both genera, are attracted to the combination of purple and gold.
Robin Wall Kimmerer, botanist and author of Braiding Sweetgrass, says of goldenrod and asters, “Their striking contrast when they grow together makes them the most attractive target in the whole meadow, a beacon for bees. Growing together, both receive more pollinator visits than if they were growing alone.”
Besides attracting hordes of pollinating insects, including migrating butterflies such as monarchs and painted ladies, asters and goldenrods are also larval hosts to many butterflies, moths and beetles, who in turn attract insectivorous birds. Later in the season, seed-eating birds, including Orange-crowned Warblers, Dark-eyed Juncos, Indigo Buntings, American Goldfinches, and American Tree Sparrows, among others, feast on the seeds. So do rodents, who in turn feed raptors. Several species of beneficial insects make their winter homes within the stalks.
Native Americans are said to have made wine out of goldenrod, in addition to using it medicinally. The colonists, after tossing the British tea into the Boston harbor, evidently brewed goldenrod tea.
The goldenrod genus Solidago contains more than 100 species native to North America, many of which are native to Connecticut. Of all the herbaceous perennials in New England, goldenrods support the greatest number of beneficial insects. Their natural habitats range from wetlands to seasides. Here we offer some goldenrod choices for different growing conditions. Many other fine goldenrods qualify, but available space will permit us to list only a few.
Dry, sunny locations
Sweet or anise-scented goldenrod (Solidago odora)
With upright, clumping habit and aromatic foliage, sweet goldenrod grows two- to four-feet high. Its plume-like clusters of flowers appear midsummer to autumn. Tough and adaptable, this goldenrod takes sun to part shade and average or sandy, well-drained soil. It is particularly important as a pollen and nectar source for native bees. This goldenrod would do well in the perennial border and many other garden locations. Consider growing it with New York aster, blazing star, and obedient plant.
Showy goldenrod (S. speciosa)
With an unbranched, clumping habit, showy goldenrod grows three to five feet high and, from July to September, is topped with dense, erect flower clusters on reddish stems. It prefers sunny locations and well-drained soils but is adaptable and will tolerate light shade and poor soils. Given its potential height, showy goldenrod is probably best at the rear of the border or in naturalized areas such as meadows and woodland edges. It would combine well with oxeye sunflower, New England aster, and switchgrass.
Gray goldenrod (S. nemoralis)
Upright, branched and sporting a stubble of short gray hairs, gray goldenrod grows six to 30 inches high. It displays narrow, wand-like panicles of yellow flowers in August and September. Gray goldenrod thrives on sunny sites with medium to dry, slightly acidic soils, but adapts to higher pH and different soil types, as well as drought. Gray goldenrod will pair well with smooth aster. It spreads by rhizomes and can thus be somewhat aggressive; thus, consider it for meadow edges or along paved areas.
Silverrod or white goldenrod (S. bicolor)
This is the only goldenrod on the East Coast to produce white (or yellowish) flowers, borne on upright, elongated stalks. Growing one to three feet high, silverrod blooms from mid-summer to fall, attracting loads of native pollinators. It grows well in dry, poor soils, in full sun to part shade, and tolerates drought. Along with wild columbine, butterfly milkweed, white aster, and smooth aster, this goldenrod can help make the most of those tough places where little else will flourish.
Part or full shade
Blue-stemmed or wreath goldenrod (S. caesia)
With clumping, unaggressive growth habit, blue-stemmed goldenrod reaches one to three feet high. Flowerheads occur along the arching stems, lending it to wreath and garland making. It blooms in August and September and, although tolerant of shade, will bloom most profusely with at least three hours of full sun. This plant will complement many garden locations. In shady locations, combine it with big-leaved, white wood, or blue wood asters and wild ginger.
Zigzag or broad–leaved goldenrod (S. flexicaulis)
This pollinator magnet grows one to three feet high and spreads by rhizomes, which can result in the plant filling in the spaces where it takes hold. Elongated flower clusters form at the end of central stalks. It prefers medium to dry soils and at least three hours of sun. Use this goldenrod in naturalized areas or where you want to replace unwanted invasive plants with a valuable native. Pair with big-leaved, white wood, or blue wood asters and Pennsylvania sedge.
Round-leaved goldenrod (S. patula)
This denizen of moist areas and sandy swamps grows up to six feet tall, usually with unbranched stalks, and blooms in August and September. It is particularly valuable to the monarch butterfly. It prefers shade and will benefit from nearby vegetation to help support it. Grow with calico aster and sensitive fern.
Seaside goldenrod (S. sempervirens)
This goldenrod grows in a clump form, topped by erect or arching stalks with striking terminal flower clusters on only one side of the stalks. It grows two to eight feet high. Best In full sun in sandy, well-drained soils, it is tolerant of drought and salt spray. Do not fertilize. This is a very late bloomer and thus especially valuable to migrating monarch butterflies. It is also a beautiful complement to the winter landscape. Combine seaside goldenrod with late purple (or spreading) aster and purple love grass.
Robin Wall Kimmerer, Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants, Milkweed Editions, 2013
Mark Richardson and Dan Jaffe, Native Plants for New England Gardens, Globe Pequot, 2018