MSU Extension Turf

Corn Speedwell

Weeds

wall speedwell, rock speedwell

Veronica arvensis

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Corn speedwell is an upright, clumping winter annual that produces small purple flowers in the spring. The lower, non-flower, portion of the plant has leaves that are round-to-oblong with rounded teeth on the margin in an opposite arrangement. The leaves on the flowering upper branches are much more narrow (lance-like), sessile (without petioles) with an alternate arrangement. The fruit is a heart-shaped capsule containing numerous yellow seeds.

Corn speedwell does not typically persist very long after flowering. Attempts to control corn speedwell in the spring are usually unsuccessful because the plant is at the end of its lifecycle. Individual plants form 10cm patches. Heavy infestations can result from extended growing conditions in the fall and cool springtime temperatures.

• Crops Affected: turf

  Management

  Corn speedwell prefers dry areas and low maintenance turf. Any conditions leading to reduced turf density will increase the severity of speedwell germination in the fall and the size of the infestation the following spring.

  Similar Species

  Several species of speedwell are common in Michigan. Other members of speedwell (Veronica) are similar in size and general appearance. Flowers of various speedwell species are mostly indistinguishable.