species. Because of their easily-identifiable fall features, some of the non-native plants that have now become naturalized in this region clearly stand out. Seven of these are among the most important invasive plants in this region, threatening the well being of our natural surroundings.

To be correctly classified as “invasive”, a plant must meet certain criteria. Invasive plants are not native to the region but have become established in undisturbed areas. An invasive plant produces and disperses high numbers of seeds, out-competes and displaces natural plants and can fundamentally change the way the ecosystem functions. But not all plants that grow vigorously can be deemed invasive. For example, plants like poison ivy (Rhus radicans) and red maple (Acer rubrum) can be aggressive, but environmentalists do not considered these invasive because they are native to the region.

Late September’s diminishing daylight and cooler nights are nature’s signal, triggering fruits and berries on many plants to begin to color-up and ripen. We can all appreciate the beauty and value of fresh fruit: who hasn’t enjoyed pick-your-own apples and colorful arrangements of autumn fruit and berries that add pleasure to our lives? As they take on their full colors, fruits in the wild also become attractive to birds and wildlife who consume them, depositing their seed in new areas where they can germinate and develop into new plants.

All of the most threatening invasive plants produce seeds and fruit. Five of them, autumn olive (Eleagnus umbellata), burning bush (Euonymus alatus), Japanese barberry (Berberis thunbergii), Oriental bittersweet (Celastrus orbiculatus) and multiflora rose (Rosa multiflora), develop distinctive, often spectacular, displays of berries in tones of red. The other two produce less colorful fruit: buckthorn (Rhamnus frangula) with its black berries from late summer into winter, and Norway maple’s (Acer platanoides) profusion of large, winged seeds that twirl and are readily spread by wind in late autumn into surrounding areas. As attractive as they may be, it would be wise to avoid picking berries of invasive species whose seed germinates readily and can create future problems as additional plants become established in new areas. Bittersweet and multiflora rose have been used traditionally as popular choices for cut branches at this time of year – a practice which only serves to spread them further.

As October’s days shorten and nights become increasingly colder, foliage on most deciduous trees and shrubs display their distinctive colors. Among the earliest of the invasive plants to color-up are burning bush (Euonymus alatus) and Japanese barberry (Berberis thunbergii) whose leaves turn brilliant shades of pink, scarlet and orange-red for several weeks. The leaves of buckthorn (Rhamnus frangula), autumn olive (Eleagnus umbellata), Oriental bittersweet (Celastrus orbiculatus) and multiflora rose (Rosa multiflora), are less colorful, turning somewhat yellowish, dropping quickly to reveal their fruit. Among the latest to color-up, often even into November, is Norway maple (Acer platanoides), with its distinctive butter-yellow foliage.

All seven of these invasive plants tolerate low light levels, can survive in shady areas and even adapt well to dry and infertile soils. These characteristics make them ideal candidates to move into natural areas, becoming serious threats to the natural beauty that surrounds us. All seven of these are readily identified by their distinctive features during this season.  As their autumn features appear it becomes strikingly clear how
strongly they have become established. And once we know where they are and observe their effects, the need for developing a plan to manage them becomes evident.

To manage invasive plants, a multi-faceted approach is most effective. Fundamental is education and communication of relevant information about what plants are invasive in which areas, and why they are causing damage. Actions to curb the increase in their spread are then appropriate, and this should be a combination of eliminating existing plants along with preventing future invasions. Once all this is accomplished, a continuing program will be needed to monitor and take action as new invasions occur.

The issue of invasive plants in natural areas may be relatively low on most people’s list of compelling priorities. But the effects of letting this problem continue unabated will most certainly adversely affect our future quality of life in this region.

To learn more, inquire at your local garden center, horticultural group, garden club, or on the internet. The website of the Massachusetts Nursery and Landscape Association is a good place to start: www.mnla.com (click on the “Invasive Plants” tab). Why not take advantage of this unique seasonal opportunity to start learning more about helping your surroundings become better for future generations?