Solidago caesia

On a wooded ridge in early October, low stems lined with yellow blossoms overlay the ground, arching brightly across the forest floor like the paths of woodland sprites made visible. The stems belong to wreath goldenrod, and as for the sprites – indeed they are present, their yellow and black bodies buzzing from bloom to bloom as they seek out pollen and nectar. With its arching growth habit, flower clusters centered along its stems, and tendency to grow in the forest rather than field, wreath goldenrod doesn’t match the common notion of a goldenrod. Observing its magnetism for pollinators and other beneficial insects, however, makes its goldenrod identity more apparent. Like other goldenrods, the plant’s shallow flowers provide nectar and pollen that’s readily accessible to flies, beetles, bees, wasps, skippers, moths, and butterflies. Among the most frequent visitors are bumblebees and several groups of metallic green sweat bees, which are some of North America’s most beautiful bees.

Research into goldenrod habitat preferences and bloom times shows some of the ways that this important group of plant species competes within itself for pollinators’ attention. When two goldenrod species occupy the same habitat, they will often bloom at different times. And when goldenrod bloom times overlap, the species in question typically occupy different habitats. Each goldenrod species thus attempts to ensure that when it blooms, it has maximum access to local pollinators with respect to other, nearby goldenrods. This point is well demonstrated by wreath goldenrod and zigzag goldenrod: although both are species of the forest with overlapping bloom times, wreath goldenrod tends to grow in drier upland woods whereas zigzag goldenrod tends to grow in slightly wetter lowland woods, such as floodplain forests.

In the garden, wreath goldenrod grows well under part shade to shade and in soil moisture ranging from moderate to moderately dry. The plant reaches a mature height of 1-3’ and produces its brilliant yellow blooms for approximately one month during the late summer and early fall.

References: 1,2,3,4,5.

Photos by Julie Slater.