Question: Should I trim my groundcover? When and how?

Answer: Groundcovers do sometimes grow too tall and trimming is a possibility. Trim mondograss and liriope by half in late winter before they start to make their candles of new growth. Their leaves are very fibrous, so use sharp tools to trim. Asian jasmine should be trimmed with your mower at its top setting, once again in late winter before the new growth begins. This is also a way to tidy up any Asian jasmine beds that have been damaged by extreme cold. Purple wintercreeper euonymus grows taller than jasmine so you'll need to use a line trimmer or gasoline-powered hedge trimmer to cut it. For the record, English ivy can pull loose from its bed if you use a line trimmer carelessly.