Thugs in the garden—some plants we choose for specific purposes have an agenda of their own, and that seems to be to take over our gardens and then the Northwest. Be warned and be vigilant.
English laurel or cherry laurel (Prunus laurocerasus), a broadleaf evergreen, seems a quick fix to a lack of privacy. Native to the Mediterranean, its spring spikes of white flowers develop into black berries, and when birds eat the fruit, seed is spread far and wide. Maintaining a regular pruning program will eliminate the flowers and help prevent the plant from spreading throughout the garden and into natural areas.
In the quest to plant a garden with layered interest, a variegated groundcover sounds like a winner, but once established, bishop’s weed (Aegopodium podagraria) can race through the garden. Also called goutweed or ground elder, it pops up everywhere, forming a dense mat that discourages other plants. Gardeners have been known to dig up entire perennial beds to get rid of it, and that’s really all you can do—dig and pull, dig and pull.
The spiny dark green leaves and berried stems of English holly (Ilex aquifolium) are seen in Northwest gardens as well as sunny forest glens. It will—and does—grow anywhere, causing annoyance in gardens and replacing native plants in the wild. But ridding your garden of this thug doesn’t mean you must give up its ornamental characteristics. Try Osmanthus heterophyllus, a shrubby hollylike replacement.
A charming, trailing groundcover, yellow archangel (Lamium galeobdolon) soon reveals its dark side—it takes over any site, sun or shade, forming a dense mat that provides neither food nor cover for wildlife. Short upright stems carry tubular yellow flowers. Only one cultivar has been found to be safe: ‘Hermann’s Pride’.
Bishop’s weed (Aegopodium podagraria)
Marty Wingate writes and gardens in Seattle, when she isn’t leading a garden tour to European or North American destinations.