Webinar presenter urges gardeners to avoid invasive plants, cites invasive.org and EDDMapS for ID

A webinar hosted through the Clackamas County Master Gardener program walked homeowners through how to choose garden plants that won’t escape into nearby natural areas, the presenter said.

The presenter opened by urging gardeners to “make a plan” before buying plants and invoked a simple principle: “First, do no harm.” She said many plants sold at nurseries are listed as invasive or noxious in at least one state and advised checking botanical (Latin) names and regional listings before purchase.

Why it matters: ornamental plants that naturalize can spread rapidly, crowd out keystone species and complicate control. The presenter used Quercus garryana (Garry or Oregon white oak) and Acer macrophyllum (big‑leaf maple) as examples of native trees that provide high wildlife value and can be threatened when invasive vines and shrubs take hold.

The presenter recommended practical steps for shoppers and stewards: identify the plant’s Latin binomial on the nursery tag, consult government or academic sources to confirm local status, and avoid plants known to reproduce or spread aggressively in your eco‑region. “Do the research,” she said, and reiterated, “You can have the garden style you want without using invasive plants.”

Resources and mapping: she pointed listeners to invasive.org (maintained by the University of Georgia/bugwood.org) and the Early Detection & Distribution Mapping System (EDDMapS) for maps showing where species have invaded natural areas and where sale or distribution is restricted. She warned there is no single database that covers every place and emphasized checking state and ecoregion listings because legal status and prevalence vary by jurisdiction.

Examples and alternatives: the presenter named several commonly available plants that can be problematic in parts of the U.S., including English ivy, wintercreeper, butterfly bush (with sale restrictions in some Oregon selections), cherry laurel and large non‑native hollies. For each role (trees, hedges, groundcovers, vines, grasses, flowers) she offered lower‑risk alternatives suited to Pacific Northwest conditions—examples included vine maple, lodgepole pine subspecies for smaller yards, toyon, Oregon grape, native mahonias and native groundcovers—and encouraged gardeners to match plants to sun, soil and water constraints.

Pollinators and plant choice: summarizing Oregon State University Garden Ecology Lab research, she noted many native bees are specialists that rely on particular flower forms; planting a diversity of shapes, heights and bloom times supports a wider range of pollinators.

Q&A highlights: in response to audience questions the presenter said her most difficult removal was English ivy and Himalayan/European blackberry at a property in Lake Oswego. She explained how to use invasive.org (search by common or Latin name, view photos, then open maps with invaded‑area and sale‑prohibition overlays) and noted that state lists sometimes differ—for example, St. John’s wort is treated differently across Pacific states—so homeowners should confirm local guidance.

Practical takeaways: remove seed heads before they spread, do not propagate or share cuttings from invasive plants, and when in doubt use photos and the resources provided by local Master Gardener programs or extension services for identification help. The presenter said registrants will receive a recording and a resource list and provided an email for follow‑up identification questions.

The webinar closed with a reminder that resources and recordings are posted on the Clackamas County Master Gardener website and a plug for a follow‑up webinar next week.