The issue: Oxalis or yellow woodsorrel (Oxalis stricta) is a weak perennial, native to eastern and central U.S. that is more of a lawn, yard and garden weed, but can invade woodlands, meadows, and field crops as well. It prefers moist soils but tolerates dry soils once established. Oxalis is…

The issue: Common tansy (Tanacetum vulgare), a creeping, spreading perennial from Eurasia, was introduced to the U.S. as an ornamental plant and for medicinal purposes.

Daybell Disappearance

Angie Dodge archive

The issue: Dyer’s woad (Isatis tinctoria) is a biennial from central Asian and Russia. Historically, it was used to produce a rich blue dye and was introduced to North America in the late 1600s for the same purpose. The plant has successfully invaded rangeland, pastures, cultivated fields an…

The issue: Summer is when weeds are most noticeable, mostly because they are large and that is the time we are out in our yards and fields. Annuals and seedlings are easy to kill. Biennials are usually going to seed during the summer months. Perennials are quite difficult to kill in the summer.

The issue: Common mallow or cheese weed (Malva neglecta) is a non-native weed that will germinate from spring through fall. Fall-germinated seedlings will overwinter and continue growth during the next spring. While it is an all-season annual, it may behave more like a biennial or even a sho…