Friday, June 14, 2019

Skyblue Aster - Symphyotrichum oolentangiense

Flowers, June 12 2019

Whole plant in my home landscape
Skyblue aster (Symphyotrichum oolentangiense) is a rather tall member of the true aster genus found naturally in only four counties in the central Panhandle region of Florida adjacent to our border with Georgia. It currently is not considered native to Florida according to the Institute of Systematic Botany site (ISB) maintained by the University of South Florida, but seems likely to actually occur here naturally and I suspect its nativity status to be changed to reflect that. Skyblue aster is a very widespread species in North America and occurs in every state north of us, except South Carolina and a few mid-Atlantic states, from Georgia west to Texas and north to Minnesota and New York. It also has been documented in Ontario. Its long scientific name is derived from the location of where it was first described by Riddell in 1835 - in open forested habitat along the Oolentangy River in Franklin County, Ohio.
Throughout its range it is most commonly found in open woodlands where it gets ample sunlight, but not full sun. In these locations, it occurs in typical woodland soils with average moisture.
In the landscape, however, skyblue aster does not seem to be particularly fussy about its growing conditions. Although it makes an excellent addition to a partly sunny location in the landscape, I have planted mine in a mostly sunny spot that is shaded only from mid-afternoon on into evening.
This is a tall and lanky species, sending up multiple stems from its base that may reach three feet tall or slightly more by fall. The basal leaves are distinctly heart shaped and about six inches long, but the leaves become more elliptical as they go up the stems.

Leaves near the base.
Despite the common name, there is variability in the flower color. The one in my current landscape is a light lavender blue - not the richer sky blue seen in other plants. The flowers can occur from early summer into early fall at the tips of the long stems. Each flower head is rather small - no more than an inch across, and with a central disc that starts out yellow in color and fades to a slate grey as it matures. Like all asters, these blooms attract the attention of pollinating insects.
This species is currently being propagated in Florida as a native wildflower. I purchased mine at Native Nurseries of Tallahassee, but I do not know their wholesale grower source. It is widely available outside Florida from wildflower nurseries. Over the years, I have tried to add as many Symphyotrichum asters to my landscape as possible to increase the diversity of my pollinator garden. So far, this species has been a good addition.