Broadleaved weeds detract from the appearance of turf and garden beds and deprive grass and garden plants of moisture, nutrients, and sometimes attract insect pests. Broadleaved weeds have wide leaves with netlike veins, compared to grassy weeds, which have parallel leaf veins. They are generally tough plants and grow aggressively. Some broadleaved weeds are considered wildflowers. Broadleaved weeds are perennials, biennials or annuals. They have an erect, vinelike or prostrate growth habit.
Prostrate Broadleaf Weeds
Examples of prostrate broadleaved weeds are carpet weed and prostrate pigweed. Carpetweed grows wherever crops are grown and is especially common in areas of newly seeded or thin turf grass. Prostrate pigweed is also called tumble weed. It grows in vegetable gardens and in lawns. Prostrate pigweed is native to western North America, but it has now spread throughout the Northeast and other regions.
Upright Broadleaf Weeds
Canada thistle and common yarrow are broadleaved weeds that grow erect. They propagate by seeds and rhizomes. Rhizomes are underground stems. The rhizomes of Canada thistle can extend about 3 feet under the ground. Canada thistle has large distinctly lobed leaves with spiny margins. In a mowed lawn, Canada thistle forms a rosette of spiny leaves. Yarrow has finely divided leaves and when mature, is topped with flat heads of white flowers.
Vinelike Broadleaf Weeds
Field bindweed has viney stems that trail along the ground or climb up on other plants and objects. Bindweed has 3- to 4-inch-long arrow-shaped leaves and morning glory-like flowers. It has a very deep root system and so is difficult to eradicate. Ground ivy or creeping Charlie, another broadleaved weed with vinelike stems or stolons, grows just above the ground. The stolons make roots at nodes along the length of the stem to form new plants. It prefers shade, but grows rapidly in thin turf even in the sun. Identify it by its scalloped, round leaves, which are about 1 inch in diameter.
Annual Broadleaf Weeds
Annual weeds die out yearly and only reproduce by seeds. Carpet weed and prostrate pigweed are annual weeds. Other annual broadleaved weeds are common chickweed, shepherd's purse and jimsonweed. Common chickweed is a small, prostrate plant, shepherd's purse forms a basal rosette from which a stem grows with heart-shaped seeds. Jimsonweed grows up to one foot tall. It is toxic to humans and animals. Identify jimsonweed by its oak leaf like leaves.
Perennial Broadleaf Weeds
The root systems of perennial weeds remains alive, even when top growth dies down so these weeds will be back. Perennial broadleaved weeds spread by seeds, rhizomes or stolons. Some even grow from chopped up root pieces. Canada thistle, common yarrow, field bindweed and ground ivy are perennial weeds. Dandelions with their scalloped leaves and yellow flowers are common perennial weeds of lawns. Red sorrel is another perennial broadleaved weed. It has a taproot just like dandelion. Some weeds are biennial; they grow for only two years.