White Panicled Aster

Photo Credit: Hardyplants, CC0, via Wikimedia Commons

The White Panicled Aster features daisy-like rays with prominent yellow discs that redden with age and make up clusters of mini-blossoms. Known as Symphyotrichum lanceolatum, it is a flowering plant native to North America in the Asteraceae family. Its common names include asters with panicles, lance-shaped leaves, and white panicles. It is a perennial herbaceous plant that can grow to a height of at least 1.5 metres (five feet) and up to 2 metres on occasion (six and a half ft).

Quick Growing Guide

Botanical Name: Symphyotrichum lanceolatum

Botanical Family: Asteraceae

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The species can be found in a variety of open, moist habitats, including riparian zones (the space between a body of water and adjacent land), meadows, and ditches. The panicked aster has a strong rhizome and can form a clonal colony as well as produce seed that is carried by the wind. Because of its rhizomatic spreading and the production of compounds that can be harmful to other plants, the species can harm ecosystems outside of its natural range, as it did in Europe when it was first introduced.

Appearance

The leaves are toothless or have a few widely spaced teeth, are lance-shaped, 1 to 4 inches long, and up to 3/4 inch wide. With the exception of a few tiny hairs around the edge, they are mostly stalkless, pointy at the tip, and hairless. Both the lower stem and basal leaves wither during flowering; the basal leaves are larger and more erratic in shape, with winged, sheathing stalks. Brown and twisted, withered leaves usually remain attached to the stem rather than falling off.

With the exception of a few lines of short hairs in the top plant and into the blooming branches, stems are straight, spherical, or shallowly grooved. However, they may occasionally flop over from the weight of the flowering branches. Long rhizomes can develop into colonies.

White Panicled Aster Flower

In general, there are 20 or more flowers per branch in stalked flowers. The top of the stem emerges from the higher leaf axils. Flowers rarely cover an entire branch on one side (second). Flowers have a yellow center disk that matures to a reddish color and is 12 to 34 inches wide, infrequently 1 inch, with 16 to 50 slender petals (ray flowers). Usually white, Ray can also be blue or violet.

The bracts (phyllaries) encircle a flower’s base are composed of three to six layers and lance-shaped, appressed to slightly spreading, and hairy. The outer layer is shorter than the inner layer. Below the flower, there may be one to several little leaf-like bracts that are differently hairy, sometimes in lines.

Fruits and Seeds

Fertile blooms develop into 0.5 to 1.6 mm long, 4 to 5 nerved, dry cypsela with a whitish pappus attached for wind dispersion. Round in shape, these seed heads resemble tiny dandelion seed heads. About 150,000 seeds fit inside an ounce, making seeds extremely light. They will germinate in a warm environment without often requiring cold stratification. The white panicled aster’s fruit is a dry seed tipped with a tuft of drab, white to yellowish hairs that helps it blow away in the wind.

Habitat

Northwestern Mexico, much of the United States, and Canada are the native habitats of Symphyotrichum lanceolatum. It can be found in a wide range of typically moist, open habitats throughout its natural range, including riparian zones, meadows, and ditches. The distribution and habitat of the infraspecies differ.

In central and northern North America, S. lanceolatum var. lanceolatum is widely distributed. In the west and southeast, it doesn’t exist. It thrives in thicket borders, meadows, streams, banks, fields, and ditches at the height of 0 – 900 meters (0 – 2,950 ft).

The plant forms colonies in low damp regions, which can be in open forests or full sun if the soil is moist, and grows from a rhizome with fibrous roots. Rich soil is not necessary. Bees, moths, and butterflies are drawn to it. This was a typical prairie tall grass plant.

Pests

Several midge species, notably Rhopalomyia asteriflorae in the flowers or buds, which causes their growth to be stunted, and Rhopalomyia strobiligemma, are known to form galls on Symphyotrichum lanceolatum where their larvae can develop.

On the leaves, the fungus Sclerotium asterisk and the leaf-blister gall midge Asteromyia paniculata coexist in a symbiotic relationship where the fungus receives additional nutrients from the larva, and the midge receives some shelter in return.

Ophiomyia curvipalpis, Phytomyza albiceps, Sumitrosis inaequalis, and Microrhopala xerene are several leaf-mining insects that are reported to eat this species. This plant will also provide food for the younger instars of the Gorgone checkerspot caterpillar (Chlosyne Gorgone).

Medicinal and Gardening Uses

Native Americans have utilized White Panicled Aster in its natural habitat for a variety of medical conditions, including nosebleeds and wounds. The Iroquois used it to treat fever in what is now eastern Canada. The Zuni used it to treat wounds and nosebleeds.

Symphyotrichum lanceolatum has been grown for use in cut flowers and as an ornamental garden plant. It was created before 1902 and has flower heads that are about 25 millimeters (1 inch) wide and with pale violet-blue ray florets. The plant was listed in the Royal Horticultural Society Plant Finder as of July 2021.

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