It’s Weed Season – Identifying Pesky Weeds for Elimination
Here’s a handy guide to identifying pesky weeds for elimination.
Bindweed – Broadleaf perennial vine with arrowhead-shaped leaves and white-pale pink flowers resembling morning glory. Likes sunny areas and climbs 6’+. Roots spread producing plants 20-30′ from main vine. Cut down vines; treat with post-emergence herbicide; mulch to prevent growth. Image from UC IPM Online
Black Medic – Broadleaf annual/short-lived perennial with small yellow flowers and clover-like leaves. Likes poor, dry soil, full sun and is 1-2′ tall by 1′ wide. Pull by hand; use post-emergence herbicide; much to prevent; discourage growth by using compost to amend soil and keeping soil well-watered.
Black Nightshade – Broadleaf annual vine/bushy plant with white or purple flowers and purple or red fruits. Likes areas with rich soil, sun or shade and is 2′ tall by 2′ wide. Every part of this plant is poisonous! Pull by hand; use post-emergence herbicide; mulch to prevent. UC IPM Online
Canada Thistle – Broadleaf perennial with gray-green spiny leaves and purple flowers. Likes sunny areas; grows up to 6′ tall by 3′ wide. Roots spread several feet from plant. Dig out; treat with post-emergence herbicide; mulch to prevent.
Chickweed – Broadleaf annual groundcover with small, star-shaped flowers. Likes areas with moist, rich soil, sun or shade and is 6″ tall by 12″ wide. Plants produce 15,000+ seeds. Pull by hand; use post-emergence herbicide in early spring; mulch to prevent.
Crabgrass – Grassy annual; lays roots where stems touch soil. Likes sun or shade and is up to 18″ tall by 20″ wide. Produces up to 150,000 seeds; seed heads look like four spread fingers. Pull by hand; spot-treat with nonselective post-emergence herbicide; mulch to prevent or use pre-emergence herbicide.
Creeping Charlie – Broadleaf perennial groundcover, scalloped leaves with purple flow clusters in late spring. Likes shade and is 4″ tall by several feet wide. Pull by hand or use a post-emergence herbicide in spring/fall; mulch to prevent.
Dandelion – Broadleaf perennial with deeply-notched leaves and yellow flowers maturing to puffballs; strong taproot. Likes sun or shade and is 12″ tall by 6-16″ wide. Pull by hand or use a post-emergence herbicide in lawns; mulch to prevent in gardens.
Nutsedge – Grassy perennial with shiny leaves and nut-like tubers on roots. Likes sun, shade, moist soil and is 2′ tall by 1′ wide. Pull by hand; use post-emergence herbicide with MSMA; mulch in spring to prevent.
Oxalis – Broadleaf perennial with light green, clover-like leaves and cup-shaped yellow flowers. Likes sun, shade and is up to 20 inches tall; grows in sunny or shady landscape, lawn, or garden areas. Leaves are edible with a sharp, sour taste, but are harmful in large amounts.
Appearance: Light green leaves that look like clover and cup-shape yellow flowers in summer and fall. The leaves are edible in small quantities and have a sharp, sour taste. They can be harmful if eaten in large amounts. Pull by hand; use a post-emergence herbicide in spring or fall; mulch to prevent.
Poison Ivy – Broadleaf perennial vine/shrub/groundcover with leaves divided into three leaflets and cluster of green berries. Likes sun, shade and is up to 15′ tall and wide. Plant contains oils that can cause a severe allergic skin reaction when touched. Oils remain on dead leaves and go airborne if burned, presenting risk of inhalation. Spot-treat with herbicide.
Spurge – Broadleaf annual with green- or purple-blushed leaves forming dense mats. Likes dry soil and is 3″ tall by 18″ wide. Pull when young/spot-treat with post-emergence herbicide; mulch/use pre-emergence herbicide to prevent.
Purslane – Broadleaf annual groundcover with fleshy, dark green leaves and small yellow flowers. Likes dry soil, sun and is 6″ tall by 2′ wide. Pull by hand/spot-treat with nonselective post-emergent herbicide; use pre-emergence herbicide/mulch to prevent.
Quackgrass – Grassy perennial with wheat-like flower spikes on slender clumps of grassy foliage. Likes sun, shade and is 3′ tall by several feet wide. Dig out, removing all of the roots; mulch to prevent.
White Clover – Broadleaf perennial with three-lobe leaves framing round, white flower clusters. Clover is a helpful weed as it adds nitrogen to the soil. Likes sun, partial shade and is 8-10″ tall by 12″ wide. Pull by hand/use a post-emergence herbicide; mulch to prevent.