Welcome to this week’s stars: Rudbeckias! Since the first lovely brown-eyed susans have just started blooming here in the Pollinator Garden at the Extension Learning Farm, it’s time for a quick feature on them and a few others of their genus.
First, let’s clear up what they’re not: despite some in the Rudbeckia genus sharing the common name “coneflower”, purple coneflowers are in a different genus – Echinacea. They are not-too-distantly related to Rudbeckias, though, since they fall under the same taxonomic tribe (Heliantheae) within the family Asteraceae. Echinaceas are not native or naturalized* to New York State, but come from warmer, drier areas of the country; though they are popular in gardens and a few might be found in the wild here.
Plants in the genus Rudbeckia are mostly herbaceous short-lived perennials, with a variety of growth habits and preferred conditions. They are mostly grown for their bright flowers, which make a cheerful addition to just about any garden. All natural varieties have blooms with yellow petals and a darker center, but domestic cultivars can come in different colors – red, for example. If planting one of these, be aware that they may not have the same benefits to pollinators as the regular coloration.
There are three species that are relevant to northern New York.
- Rudbeckia hirta
- R. triloba
- R. laciniata
Let’s start with the common black-eyed susan, R. hirta. It’s native to most of eastern North America, but only considered naturalized* to most of our state, including St. Lawrence County. Despite being one of the most common and popular Rudbeckias, this species is a bit unusual in the genus because it is shorter lived than others, mostly acting as a biennial (two-year life cycle), and puts down a taproot.
Black-eyed susans can do well in a wide range of soil conditions, and are considered highly drought tolerant. They are also tolerant of juglones, the toxins excreted by walnut-family trees into nearby soil, which can prevent many plants from thriving in those areas. Black-eyed susan was historically used by Native Americans for a variety of internal and external medicinal applications. It is still used by some people in a manner similar to the related Echinacea, and is claimed to stimulate the immune system, though the effectiveness of either plant is widely debated. The part primarily used for these preparations is the root, and the seed heads are considered poisonous even by people promoting the plant’s use.
Brown-eyed susans, R. triloba, also known as three-lobed rudbeckia or thin-leaved coneflower, is next up. This species is labeled ‘Unknown Native Status’ in the New York Flora Atlas, with a note that it is considered native to some parts of the state and naturalized in others. In either case, it’s present in a scattered distribution across much of NYS, including St. Lawrence County. Brown-eyed susans have a more branching growth pattern than the other species here, with the smallest, roundest flower petal shape among the Rudbeckias, and more numerous flowers on each plant as well.
The one species that is definitively known to be native to our area, as well as most of NYS and the rest of North America, is green-headed coneflower, R. laciniata. Other common names for it include cutleaf coneflower, wild goldenglow, and sochan, derived from its Cherokee name.
