Don’t Let Aliens in Your Garden

No, this is not a political comment on illegal immigrants.  I’m referring to plants that are alien or not native to our part of the world, particularly ones that are considered invasive.

What is an invasive?

The US Government defines an invasive species as one not native to the ecosystem in consideration and likely to cause economic or environmental harm. This is an important point as there are many non-natives which do not spread rampantly or cause harm to the environment. Queen Anne’s Lace is a good example. It has become a common field plant which benefits pollinators and isn’t harming the environment.

Invasive species are considered to be one of the 2 greatest threats to native plants and animals after loss of habitat. There are invasive plants as well as insects and animals, all doing great harm to the ecosystem. Think emerald ash borer and purple loostrife to name just two.

Why are invasives a problem?

Invasives displace and even eliminate some native plants which effects the ecosystem and food sources for insects, birds and animals. This is one of the reasons many birds are diminishing, their habitat is being destroyed by building, farming techniques and invasive plants. According to Cornell ecologist David Pimentel environmental damage from invasives amounts to almost $120 billion each year. Close to half the US list of endangered and threatened species are because of nonnative invasives taking over their habitat.

How did invasives get here?

Many are introduced accidently like the ash borer in wood pallets or seeds on traveler’s shoes or clothing. However, the Brooklyn Botanic Garden discovered in their research that about half the invasive plants were brought here intentionally for horticultural use. A good example of this is Japanese knotweed which was introduced at the Pan American Exhibition here in Buffalo at the turn of the last century and Japanese barberry which is a very common ornamental shrub. This is where we come in and can add to the problem through our plant choices.

How do invasives become problematic?

Most commonly they have no predators here. When you see a plant tag that says pest free, that’s because our native insects can’t utilize it as food. Native plants and animals (including birds and insects) evolved together to form the natural food web. People don’t realize that many species are plant specific. Remove their food source and they die out. The best example of this is the interrelationship between Monarchs and milkweed.

Along with not being utilized as food invasive plants may sprout earlier and shade out the native plants or have a faster growth habit and take over the space faster than the native plant can compete. Others have allopathic properties which give the advantage. Garlic mustard is an example of this. It actually has a chemical that prohibits other plants from growing near it. Walnuts have this as well although there are native walnut species. 

What can we do?

So we, as gardeners, have a responsibility NOT to continue planting invasives. We tend to be drawn to the newest and most exotic plant to add to our garden without considering its origin or whether it contributes to the overall ecology. Basically we need to start planting to support nature not just to please ourselves. The result can be just as beautiful. Luckily there are native plants appropriate for any site where invasives grow. Before you purchase a plant check the NYSDEC web site to see if it’s listed as an invasive.

Why replace with natives?

Natives are the plants that nature relies on for food. They evolved along with animals, birds and insects to form a self-sustaining ecosystem. Basically our native plants and animals depend on each other. Invasives disrupt this balance. Planting native trees, shrubs and perennials not only helps the ecology but they are easier to take care of, and have fewer disease and insect problems. It’s a win – win situation.

Where can you get native plants?

Ask your local nursery. If enough people ask, nurseries will make sure they have natives in stock. There are some nurseries that carry natives: Lockwood’s, Johnsons, Murray Brothers and Lavocat’s. A good place to get native plants is at my Annual Perennial Sale, May 19, at my home in E Aurora (170 Pine St.) from 9:00am – 2:00pm. I have quite a few varieties along with non native perennials for sun and shade. Ellen Foltz from Amanda’s Garden comes and brings an excellent selection of all natives. Between us we have a larger selection of native plants than anywhere in WNY. Come early, we sell out fast.