Many Delaware gardeners are unaware that a number of plants, shrubs and trees they may have planted in the past can no longer be purchased. The Invasive Plants Law of Delaware (which went into effect in July 2022) lists plants that experts have identified as invasive and therefore illegal for nurseries to “import, export, buy, sell, transport, distribute or propagate.” What is a gardener to do?

First, it is important to understand that invasive plants destroy the natural environment. Invasive plants grow rapidly, crowding out the native species which the region’s native insects and native birds rely upon for survival. Both our native insect and native bird species have been in steep decline over the past 50 years.

There are several reasons for these declines, and a significant one is the loss of native plants to invasive species. Another fact about invasive plants is that they are often magnets for non-native, destructive insects. The non-native, invasive tree of heaven, for example, is a favorite of the spotted lanternfly.

Most invasive plants did not start out that way. Over time, however, as they adjusted to their new environments, they were able to spread because the natural predators that kept them in check in their native lands are not here. Some nonnatives, such as the Callery (Bradford) pear, underwent genetic adaptations which allowed them to thrive. The effect of the Callery pear’s escape is evident all along Route 1 in Delaware. The trees look beautiful until you realize the destruction that they are causing.

Many plants on the list were at one time commonly recommended landscape plants. The list includes often-used trees such as Norway maple (Acer platanoides), tree of heaven (Ailanthus altissima) and Callery (Bradford) pear (Pyrus calleryana); shrubs like common privet (Ligustrum vulgare), Japanese barberry (Berberis thunbergii) and burning bush (Euonymus alatus); perennials such as the orange daylily (Hemerocallis fulva); and ground covers like English ivy (Hedera helix) and Japanese pachysandra (Pachysandra terminalis).

Your property probably has at least one item from this list. Although the law does not apply to homeowners, many of these plants continue to be shared at plant swaps by well-meaning friends. When people learn what these plants are doing to our bird population, they are usually eager to become better stewards of their property.

If you have some invasive plants on your property, and you would like to provide a safer haven for native birds, attract more butterflies and other pollinators, and/or simply do something beneficial for the environment, you have a number of options. Some people simply remove flowers before they turn to seed, or snip off berries that a hungry bird might try to eat. Birds will eat nonnative berries (which are less nutritious than native berries) and unwittingly spread the seeds. Removing berries and flowers is a simple but tedious way to protect the birds that visit your property. If you have the means, energy and inspiration, it might be time to completely renovate your garden with native plants. If a complete renovation is not possible, try to replace a manageable number each year.

For replacement ideas, search online for “Plants for a Livable Delaware,” a pamphlet that explains in more detail the problem with some specific invasive plants and provides descriptions and photographs of alternative plants. You can also visit Mt. Cuba Plantfinder online for more information and ideas. Another site, Missouri Botanical Garden, describes the best growing conditions for any plant you might consider planting. Use the botanical name when calling nurseries, as common names can vary from place to place.

Before you dig any new holes on your property, call Miss Utility who will (at no cost) mark your property for underground utilities. Take care not to plant trees too close to your house or to utility lines.

Delaware has dozens of beautiful native trees and shrubs of all shapes, sizes and colors. When it comes to flowering native plants and other native perennials, you have hundreds to choose from. Native ground covers also come in a wide variety that include flowering species, ferns, sedges and even a native pachysandra. The soil and light conditions on your property will dictate which plants will best succeed.

Bring more beauty and life onto your property by replacing harmful invasives with beautiful native plants. The birds - and future generations - will thank you.

For questions on this subject or any gardening topic, call the Master Gardener Helpline: In New Castle County, 302-831-8862; in Kent County, 302-730-4000; and in Sussex County, 302-831-3389. For information about master gardener workshops, visit udel.edu/master-gardeners and click on Garden Workshops.