Spiked Loosestrife  (Purple Loosestrife)

Lythrum salicaria

A showy plant with striking pink or purple floral spikes consisting of many six-petaled flowers surrounding the stem. Most easily distinguished from other species of loosestrife by its leaves, which are slightly hairy, long, narrow, pointed, with obtuse bases that directly adjoin the main stem and occur in opposite pairs or whorls of three.

Always found in wet locations, Spiked Loosestrife is a highly invasive alien (originally from Eurasia), brought for its bright blooms but now escaped from cultivation. It forms dense colonies that crowd out native species and can be difficult to eradicate.

It is sometimes called Purple Loosestrife, a name also applied to another related alien species, Lythrum virgatum, which I have not (yet) identified in Jackson Park.

2-4 feet, sun - partial sun. Moist ground or marsh.

Summer (June-September).

24 July 2020.

Spiked Loosestrife, 27 August 2020.

Leaves long, narrow, acute at tips but broad-based and sessile (directly attached to main stem); covered with slight hairs.

24 July 2020.