Invasives

Kay Hinkle
Adams County Master Gardener

Now that the Christmas holiday is coming to a close and the new year is upon us, it is time to begin planning for spring gardening. The growing season is right around the corner! Bulbs will bloom and a new array of annuals and perennials will soon appear at your local nursery. Seeds started on windowsills will be bursting into mouth-watering vegetables in no time at all! The cycle of life is so very exciting in the world of growing and gardening. The fruit of our labors are both rewarding and tasty.

Not quite so exciting is the world of turf grass and the weekly chore of mowing the lawn. However, a neat lawn free of weeds and neatly mown will serve to highlight the plantings in garden and enhance our homeís curb appeal. The contrast of bright green against shrubs and flowers is striking!

And then less exciting but no less important is the world of weeds, which is the topic of discussion here. All of the time and effort invested in planting our gardens and cutting our grass can be thwarted if we donít pay careful attention to unwanted weeds that plague us during the growing season. Some are easily managed by removing them as they pop through. Some weeds, though, are lurking below the surface just waiting to take over every inch of available growing space, thereby taking over the garden and our landscape. Some of these weeds have been introduced into our region (non-native) and threaten our environment.

Of growing concern is a category of unwanted plants we call invasives. An invasive species is a plant that is not native to a specific location (an Introduced species) and has a tendency to spread, which is believed to cause damage to the environment, human economy and/or health.

One common invasive (pictured in this article) is the kudzu vine, a climbing, coiling, trailing perennial vine native to much of eastern Asia, southeast Asia and some Pacific Islands. Kudzu is easily visible along highways, particularly in southern states. Kudzu literally grows in walls of green that cover and smother native vegetation. In an effort to control the growth of this plant, the city of Chattanooga, Tennessee has introduced a program that includes goats and llamas to eat the fast-growing plants. When left uncontrolled, kudzu will eventually grow over almost any object including other types of vegetation. Over a period of several years it will kill trees by blocking sunlight. It was first introduced in the early 1900ís in Florida as a forage crop and quickly found to be difficult to control. It is a real problem in the south today and a classic example of a detrimentally deadly invasive.

Japanese Knotweed is another invasive that is easily visible from the road when driving through Central and Northern PA. I first noticed this vegetation in the fall when it blooms profusely pushing white flowers that are very attractive. Upon further investigation, I learned that this plant is another fast-growing invasive that threatens our native Pennsylvania Mountain Laurel. Invasive plant species like Japanese knotweed are a considerable threat to biodiversity. Once these species are well established it is sometimes impossible to remove them. When removal is possible, it comes at a high cost financially and ecologically. Researchers at Cornell University estimate that invasive species are costing Americans more than $130 billion every year. Controlling a single unwanted invader can carry a price tag in the millions.

Finally, we all know purple loosestrife as a perennial that blooms profusely throughout the summer. It is known as a nice addition to bogs and fish ponds because its roots donít mind being wet. However, purple loosestrife, first introduced to our area as a planned part of our home landscape, has become invasive and overtaken low lands and natural bogs in many marshy areas. It is a non-native plant that threatens significant portions of our marsh, swamp, and coastal habitats. By crowding out native wetland species, purple loosestrife can reduce biodiversity, eliminate food sources for marsh animals and change water flow patterns.

We have just scratched the surface of this very dynamic topic of invasive plants. To learn more, download fact sheets from Invasive Plants in Pennsylvania. To learn how you can prevent and control invasive species on both public and private lands, access the DCNR Invasive Species Management Plan. Using native plants in the landscape will help avoid some of the problems caused by invasive plants. Finally, www.iConservePA.org will help you begin this work!

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