Wednesday, August 17, 2011

Summer whites

Every September, I scavenge my wooly backyard and the abandoned lot next door to bring my secretary a wide mouth Mason jar filled with brightly colored late summer wildflowers. They’re seldom celebrated like spring wildflowers, but the early goldenrods, sunflowers, tall, rangy polygonums, and dome-like plants of the genus Eupatorium always make lovely arrangements for her gray walled cubicle. As August progresses, so too does the bloom cycle of the white flowering composites-- the bonesets, thoroughworts, and white snakeroot, all common and widespread throughout the Ozarks.

Plants of the genus Eupatorium occupy a wide range of landscape types, from prairies and fens to woodlands and streambanks. There are also species in the genus that are loyal to trash dumps and roadsides. Several years ago, on a visit to an overgrazed hardpan prairie in southwest Missouri, I learned firsthand what Julian Steyermark states in his description of Eupatorium serotinum (“the weediest of the genus”): “…like other members of the genus, it is usually avoided by grazing animals.” While looking out across the prairie, it was clear that ruderal species abounded, among them, E. serotinum (CC value=1) and E. altissimum (CC value=3). The plants that grazing livestock avoid are the plants that colonize overgrazed land to the exclusion of the ice cream plants (invariably the plants with higher CC values).

And, unfortunately, such is the state of many of Missouri’s formerly high quality native prairies, now dominated by grazing increaser plants.

E. perfoliatum (CC value=5, pictured) can be found in high quality fens in the Ozarks and in moist areas, along streambanks, at the base of moist cliffs, in wet prairie, marly fens and seeps on glades. The textured leaves wrap completely around the stem (perfoliate) and have widely spaced soft white hairs. Growing to approximately three to four feet tall, the white flowers of E. perfoliatum make a statement in the fen matrix where it blooms alongside the bright yellow Rudbeckia fulgida. While cows avoid E. perfoliatum on the prairie, deer clipped the stalks and leaves to nubs in my fen sampling plots this summer.

E. rugosum is a common Ozark woodland plant that begins its bloom cycle in early August. It can be found in dry rocky uplands, and in woodland borders where it grows to approximately 2 feet tall. Bushy in form with bright white flowers, E. rugosum is always present in my late summer bouquets. Deer do not favor this plant, and in woodlands with deer overpopulation problems, this plant can spread quickly and become the dominant groundcover in the fall. Known as white snakeroot, this plant contains the toxin tremetol which causes an illness in domestic livestock that can poison milk. In the early 1800s, milk sickness caused by livestock eating E. rugosum killed hundreds of early settlers, including Abraham Lincoln’s mother. In 1818, almost all the residents in Pigeon Creek, Indiana died from this illness. Read here a well researched account from an Appalachian history website about milk sickness, about the Ohio farmer who discovered the plant that caused it and the medical doctor who tried to discount his discovery.

Not a Eupatorium but in the same tribe, Kuhnia eupatorioides (pictured) begins to bloom in late August on dolomite glades and rocky ledges in the Ozarks. Find it blooming alongside the deep yellow blooms of Helianthus occidentalis and Solidago gattingeri. With the recent rains and clement temperatures, the late summer wildflowers are in peak form these days.

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