Sowthistle

Sowthistle (Sonchus oleraceus), also known as common sowthistle or annual sowthistle, is a fast-growing annual broadleaf weed from the daisy family (Asteraceae). It is commonly found in lawns, gardens, pastures, and along roadsides. Sowthistle thrives in disturbed soils and can grow up to 1.5 metres tall. Its ability to spread quickly through wind-dispersed seeds makes it a persistent problem in many environments.

Characteristics of Sowthistle

• Appearance: Sowthistle has bluish-green leaves that form a basal rosette during early growth stages. The leaves are lobed, with toothed margins, and clasp the stem at the base.

• Flowers: Bright yellow flowers resembling dandelions bloom at the ends of stems and branches. These flowers produce fluffy white seed heads that disperse seeds widely.

• Growth Habit: Sowthistle grows upright with hollow, unbranched stems that exude a milky sap when cut.

• Taproot: The plant has a slender taproot that anchors it firmly in the soil.

Sowthistle is can be a troublemaker in your garden. It can quickly crowd out your plants by fighting for water, nutrients, and sunlight. With its fast growth and abundance of seeds, it can take over lawns and gardens in no time. Plus, its milky sap makes removing it a messy, frustrating task—so it’s best to tackle it early!

You can identify sowthistle by its bluish-green leaves with toothed margins that clasp the stem at the base. The bright yellow flowers resemble dandelions and produce fluffy white seed heads after blooming. When cut or damaged, the plant exudes a milky sap from its stems and leaves.

Lawn Care Practices

• Keep Your Lawn Healthy: A thick, healthy lawn makes it harder for sowthistle to grow. Fertilise regularly, water deeply but not too often, and mow at the right height.

• Loosen the Soil: If your soil is hard or compacted, aerate it. This helps with drainage and makes it harder for sowthistle to thrive.

Manual Control

• Pull by Hand: For small patches, pull sowthistle out by hand when the soil is damp. Make sure to get the whole root, or it will grow back.

• Mow Often: Mowing stops sowthistle from flowering and spreading seeds, but it won’t get rid of fully grown plants.

Using Weed Killers

• Selective Herbicides: Use selective weed killers made for broadleaf weeds (like ones with 2,4-D or dicamba). These kill sowthistle but won’t harm your grass. Apply during spring or early autumn when the plant is actively growing.

• Spot Spraying: For small areas, spray directly on the weed. This uses less chemical and protects nearby plants.

Prevention Tips

• Stop the Seeds: Remove sowthistle before it flowers and forms seed heads to prevent it from spreading.

• Check Often: Keep an eye on your lawn and pull out young sowthistle plants before they get bigger.

As mentioned earlier, you can use selective herbicides to deal with sowthistle and other weed issues. Some effective options include:

3D Herbicide

3D Herbicide 10L is a reliable sowthistle weed killer. It’s one of the best ways to get rid of tough weeds like sowthistle without damaging your lawn. It targets a wide range of broadleaf weeds and sedges, and it’s safe to use on grasses like Couch, Fescue, and Kentucky Bluegrass. Whether you’re caring for your home lawn or a larger space, it offers long-lasting results with minimal impact on the environment.

Amgrow Multi-Weed All Purpose

Amgrow Multi-Weed All Purpose Lawn Weeder can help you take control. It targets common weeds like bindii, clover, dandelion, dock, and sowthistle—without damaging your grass. With regular use, you’ll enjoy a healthier, greener lawn all year round.

Yates Zero Weedkiller 24HR Action

Yates Zero Weedkiller 24HR Action – 750ml RTU is a fast and powerful weed killer that works quickly, including on tough weeds like sowthistle. Its systemic formula kills weeds from the inside out, targeting roots for complete elimination. You’ll see results in just 24 hours, with no mixing required—just apply directly to the weeds.

For other sowthistle weed killer, you may browse our Garden Control Range or check out the products below.