The Most Common Weeds In Pennsylvania

most common weeds in pennsylvania: ultimate guide to identifying broadleaf weeds

Identifying The Most Common Weeds In Pennsylvania

In this article, we have created the ultimate guide to broadleaf weed identification and the most common weeds in Pennsylvania turf grass. Although this post is focused on Pennsylvania turf grass, this guide is also useful for the surrounding states.

Before coming up with a broadleaf weed management plan for your turf, we recommend you refer back to this article to make sure you have correctly identified the weeds in question. Spraying the wrong chemicals can be devastating to your lawn, and to more importantly to our environment.

Rosette/Upright Broadleaf Weeds

Dandelion – Perennial

If you’re a home owner, odds are you have dealt with dandelions. They form a rosette, a circular arrangement of leaves. In flowering plants, rosettes usually sit near the soil. The rosettes on dandelions are long, ugly, and thick taproots that can penetrate several inches into the soil, making them very hard to eliminate. Bright yellow flowers, the easiest way to identify dandelions, are produced on long stems in the spring. The dandelion’s seed head looks like a large white “puff-ball” and easily blow seeds off the stems which allow them to spread incredibly fast.

dandelion ultimate guide to identifying broadleaf weeds
Notice the rosette shape, and the yellow flowering heads

Plantain – Broadleaf and Buckhorn

Another very common weed are Plantains, which come in two different forms, broadleaf and buckhorn. The leaves on broadleaf plantains, as you may have guessed, are much broader and thicker in size than buckhorn plantains. Notice on both, the long seed heads that can grow from 5 to 10 inches tall. Plantains have very thick tap roots that grow deep into the soil, similar to dandelions.

Thistles – Biennial or Perennial

If you haven’t seen thistles in your lawn, you can almost guarantee you have seen these nasty weeds pop up in your garden bed. Thistles can be categorized as biennial or perennial.

Perennial thistles grow tall during their first year, but can be easily removed as they have a weaker root system. Biennial thistles take two full years to complete their life cycle. During the first year, these weeds grow their root systems, leaves, and store energy for the future. In the first year, thistle will have a rosette like growth, where the flowers are low to the ground and can easily hide under lawn mower blades. If you do not remove thistle in the first year, they will reproduce extremely fast and be a nuisance for your lawn, especially during the second year. If left untreated, biennial thistles will outgrow the rosette shape and grow extremely tall. Each time they are mowed they will spread seeds farther and farther.

Oxalis – Perennial or Annual

Sometimes known as woodsorrel, Oxalis is a light green upright weed that can be either a perennial, or summer annual weed. Oxalis are commonly confused with clovers, since they both have three leaflets. However, Oxalis can be distinguished from other weeds by their distinct heart shaped leaflets. The flowers on Oxalis are bright yellow, and have five petals. Annual Oxalis (and almost any annual weeds) are much easier to treat than perennial weeds.

oxalis ultimate guide to identifying broadleaf weeds
Heart shaped leaves, and yellow flowers.

Creeping Or Prostrate Broadleaf Weeds

Knotweed – Summer Annual

Prostrate knotweed is a low growing summer annual. These weeds love to grow in compacted and high traffic areas such as along side walks and in athletic fields. Prostrate in botany means the plant grows flat to the ground, and not upward like a dandelion. One of the distinct features of the knotweed is the papery sheath at the base of each leaf.

Common Chickweed – Winter Annual

Although technically classified as a winter annual, common chickweed can grow and flower at any time of the year. The leaves on chickweed are small and taper to a point. Common chickweed spreads in turf grass, through branches and above ground stolons. The flowers are small and white with five petals. These weeds prefer moist shaded areas, but can also grow in sunny areas. They prefer high mowing conditions, which makes them a pain to treat.

common chickweed ultimate guide to identifying broadleaf weeds

Purslane – Summer Annual

Purslanes are easily one of the ugliest weeds that can grow in your turf grass. They can be easily identified by the the thick, sprawling red stems. The leaves are thick and fleshy, and the flowers are yellow. These nasty weeds are prolific seed producers, and can even produce seeds that may lay dormant in turf grass for years before germinating.

purslane most common weeds in Pennsylvania
Thick red stems are a dead giveaway for Purslane.

Ground Ivy – Perennial

Ground ivy, or what we call “Creeping Charlie”, is a nasty low growing perennial broadleaf weed. The leaves on ground ivy are either round or almost kidney shaped. The stems are square, creeping and long on thee turf grass invaders, giving them an added edge when trying to take over turf grass. In the spring you will notice they have purple or blue flowers. Creeping Charlie loves to grow in poorly drained soils, with a lot of shade. They can survive in sunny areas, but have a more difficult time.

creeping charlie ground ivy most common weeds in Pennsylvania
Low growing stolons allow these weeds to avoid lawn mower blades.

White Clover – Perennial

Clover is very common in just about every area turf grass grows in. This is one of the most common weeds in Pennsylvania turf grass. Clover can actually blend in with turf fairly well, and some homeowners actually don’t mind a small amount of clover in the lawn. It grows in dark green patches, and can over take lawns because of it’s creeping growth habit. When clover flowers, you will see a small white flowers that are only 1/2 an inch in diameter. As we stated earlier, do not confuse Oxalis and White Clover for the same weed.

How To Control The Most Common Weeds In Pennsylvania

Timing for controlling the most common weeds in Pennsylvania is crucial. Early Spring or In the Fall are the most ideal times to treat weeds. Ensuring proper cultural practices such as lawn aeration, weekly lawn maintenance, proper fertilizing, and dethatching will all help give your turf grass the best shot at crowing out weeds. Be sure to follow the directions on the label and spray or apply granular fertilizers at the proper intervals. We recommend using the selective herbicide Trimec which can be bought over the counter or online. Trimec is extremely effective at killing weeds, while simultaneously not hurting healthy turf grass.