English ivy (Hedera helix) creates a dense ground cover with attractive dark green foliage.  But, left unchecked this introduced species invades woodlands, climbs (and kills) trees and is considered an invasive species. Spring is the best time to control English ivy.  However, control just got a bit more difficult for homeowners because many weed control products in garden centers no longer contain the most effective active ingredient.  Perusing the internet you can find several “recommendations” for controlling English Ivy.  Some good, some are questionable.  What does the research say?  This fact sheet summarizes some of the non-chemical and chemical control options.