Invasive plants are common in all lawns. It's important to recognize when your lawn has them because, if they go untreated, they can harm your other plants and vegetation by stealing the available water, sunlight, and essential nutrients. The first step to protecting your lawn from invasive plants is knowing what they look like. Some of them can easily be mistaken for pretty plants!

Knowing what the common types of weeds look like will help you identify them right away before they have the time to take over your lawn and create a larger issue. Below are 6 common types of invasive weeds in the Happy Valley, Oregon area, what they look like, the conditions they thrive in, and more.


1. Giant Hogweed

Giant Hogweed is a toxic plant that can grow over 14 feet tall with rigid stems up to four inches in diameter. Its leaves can be up to five feet wide. Because it is a perennial plant, it will sprout each year and spread quickly without weed treatment. Giant Hogweed is common in Oregon. If you notice it on your lawn, it is worth it to contact a professional to remove it because the leaves and sap can produce rashes within 15 hours of contact. If you don't do anything to eliminate Giant Hogweed, its large leaves will shade your other plants and block them from needed sunlight.

Close up of a giant hogweed plant.


2. English Ivy

English Ivy is a perennial vine that thrives in sunny conditions and moist, nutrient-dense soil. You can typically find it around edges, fields, and forest openings. English Ivy is an aggressive weed. As the plant grows, it attaches itself to tree trunks, branches, and twigs, blocking foliage from sunlight. You can identify English Ivy by its leaves, which are:

  • Waxy
  • Dark green with white veins
  • Leathery to the touch

A wall of English Ivy.


3. Purple Loosestrife

At first glance, Purple Loosestrife looks like a beautiful plant. Its magenta flowers that grow on tall, narrow stalks can easily fool you into thinking that it isn't an invasive weed. Purple Loosestrife thrives in wet soils, making ditches, stream banks, marshes, and lakesides its ideal growing areas. However, it can reach pastured land with full sun or partially shady locations.

The growing season of Purple Loosestrife is between July and October and it can be found in most areas in Oregon areas. This plant may look nice, but it offers no value for local wildlife and can crowd out nearby native plants by taking nutrients from the soil.

A few purple loosestrife weeds in a field.


4. Kudzu

Another aggressive plant in Oregon is Kudzu. This vine grows quickly, up to a foot a day, and can exceed 100 feet long due to its edible seeds that birds and mammals eat and spread throughout the area. Kudzu includes compound leaflets with fragrant purple flowers that bloom late summer to early fall. If not taken care of, it will engulf vegetation, road signs, buildings, and fences.

Kudzu prefers to grow in areas that are:

  • Open, like forest edges
  • Sunny
  • Warm

Kudzu covering the ground and trees on a property.


5. Old Man’s Beard

Old Man's Beard has wood stems that can grow up to 30 yards long. These wood stems have papery, wide-spaced leaflets and fragrant white flowers that bloom between December and May. Its feathery gray seed heads give this invasive weed its name.

Old Man's Beard is a very common perennial plant in Oregon. It prefers to grow under trees in warm, humid climates and can spread quickly because of its seed dispersal. Seeds can travel by water, wind, and animals. This weed can grow up to six feet a year, and damaged stems can resprout.

Close up of an Old Man's Beard plant.


6. Garlic Mustard

This invasive plant sounds more pleasant than it actually is. Garlic Mustard is a winter annual noxious weed that can grow up to six feet tall or remain a few inches high, depending on its environment. The plant is recognizable with its kidney-shaped lower leaves, triangular upper leaves, and garlicky smell. Garlic Mustard spreads rapidly and can be found in the parts of Oregon that are dark and shady, such as hedge edges.

Close up on a couple of garlic mustard weeds.


Don’t Let Invasive Oregon Weeds Take Over Your Backyard – Call Us Today!

J&C Lawn Care is the top-rated lawn care service serving Happy Valley, Troutdale, Gresham, East Portland, and surrounding areas in Oregon. We provide unparalleled services to keep your yard in the best condition, including weed control. Call our team today at (971) 284-2035 for a quote.