It’s nearly fall planting time in the Northeast – a time when gardeners seek out container plants to fill in holes in perennial beds or plant trees, shrubs, and new beds. But a recent study, reported by the Weed Science Society of America, suggests we need to be cautious of what could be hitching a ride with any container plants we buy. The study, done in Alaska, examined container-grown vegetables, herbs, perennials, and woody trees and shrubs purchased from 29 nurseries supplying Alaska gardeners and landscapers. Over a two-year period, 54 weeds or invasive plants were incubated from the soils in the purchased containers. Of the 54 weeds, only 3 were native to Alaska.
Balled or burlap trees and shrubs held more weed seeds than veggie, herb, and perennial containers, and – surprise! – so did soil-based planting mixes. Also, vendors with "superior weed control practices" sold plants with few or no weeds.
So, if you’re wondering where in the world that weed came from, it could very well have hitchhiked in with a recently purchased container plant – more proof that vigilant weeding at both the nursery and home level is good practice.