Lady's Thumb & Pennsylvania Smartweed

Above: Pennsylvania Smartweed in Oak Savanna in Madison, Wisconsin. (9/02/21).

Lady's Thumb - Persicaria maculosa (Introduced/Naturalized)

Pennsylvania Smartweed - Persicaria pensylvanica (Native)

Lady's Thumb and Pennsylvania Smartweed are part of the buckwheat family (knotweed). Persicaria maculosa grows up to 32" and Persicaria pensylvanica grows from 2' – 5' tall.

These two flowers are very similar in appearance and grow in similar habitats. A distinction that I failed to capture in many of my photos is the membranous sheath (ocrea) that is at the base of the leaf stalk. The ocrea of Lady's thumb has bristly hairs at the top that are about 1/8 inch long. The ocrea of Pennsylvania Smartweed has a smooth top and does not have bristles.

Lady's Thumb flowers are pink to deep purple in color, and densely packed spike-like clusters from 1/2" - 2" long.

Pennsylvania Smartweed flowers greenish white to rosy pink in color, and are slightly nodding with spike-like clusters to 2" long.

Lady's Thumb blooms from July - Sept.

Pennsylvania Smartweed blooms from June - Sept.

Other Names for Persicaria maculosa: Heart's-ease, Spotted lady's-thumb, Redshank.

Other Names for Pennsylvania Smartweed: Pinkweed

For more information on Lady's Thumb, visit Wikipedia.

For more information on Pennsylvania Smartweed, visit Wikipedia.

Or, visit the UW-Madison Wisconsin State Herbarium website page about Lady's Thumb - Persicaria maculosa.

Or, visit the UW-Madison Wisconsin State Herbarium website page about Pennsylvania smartweed - Persicaria pensylvanica.

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