Capeweed (Arctotheca calendula).

Capeweed, is also known as the Cape Dandelion, and is an annual weed with a low growing, flat rosette of leaves. It is very difficult to control, poisonous and indigestible if eaten in large quantities. In livestock, it causes respiratory issues and stringhalt in horses.

After you read this, you will be able to:

• Identify Capeweed or the Cape dandelion.
• Know its habitat.
• Know the best options to control the Cape dandelion.

In cool, cloudy weather, nitrates can rise to high levels in the Cape dandelion. These nitrates then suppress plant Magnesium and iodine levels and cause tetany. Milk may also become tainted when dairy cattle eat this weed.

Why is Capeweed a Problem?

• It has a deep taproot. This enables it to survive in dry conditions.
• The Cape Dandelion produces a lot of seeds and these can remain viable for several years. Under favourable conditions it produces over 4000 seeds a season.
• These seeds move by human activity, animals, wind, water and also in grass clippings.
• The rosettes of Capeweed are large. This means that the plants are able to compete strongly with turf grass.
• It is very competitive for water, nutrients and light.

Category: The Cape Dandelion is a Broadleaf (Dicot) weed.

Flower: Capeweed flowers in the late Winter and the Spring. You can often see this weed in Canberra by the side of roads as a bright flush of yellow flowers.

The flower heads look like a Daisy, and the flower is made up of several small yellow flowers. It is 15 mm across and has a black-to-brown centre. The flowers are on individual stalks about 200 mm long.

Height: It grows up to 30 cm in height.

Leaf length: The leaves of Capeweed are 5 to 25 cm long.

Leaf width: Capeweed leaves are 2 to 6 cm wide.

How Does Capeweed Reproduce?

• Capeweed spreads by seeds, and a single plant produces over 4,500 seeds.
• If you don’t carry out regular control measures, weed populations quickly spread and take over.
• When it dies off over the Summer months its own seedlings can establish in the bare areas.
• The woolly seeds stick to clothes, and also spread by the wind.
• This woolly coating also helps with the early germination of this weed.

Habitat: This weed is present on most soil types but prefers sandy soils and loams. The presence of Capeweed is a good indicator of high soil P or N.

More on lawn and turf grass weeds is in our weed ID chart.

• If you have just a small or relatively new Capeweed infestation, you can simply dig it up by hand.
• Take care to make sure that you remove all the plants before they flower. This stops them from dropping seeds.
• Cape Dandelion seeds can germinate the following year, and for up to seven years after that.
• To prevent re-growth, make sure that you cut the fleshy taproot well below ground level.​
• Mowing is only effective if you repeat this regularly. If you mow at a low enough height of cut it prevents the weed from flowering.

Capeweed is difficult to control with post emergent herbicides as its cover of wooly hairs make it hard to wet.

This means that when you use post emergents you need a wetter to ensure good herbicide contact and uptake. We recommend Optispread 1000.

Pre-Emergent Herbicides for Capeweed Control.

There are several pre-emergents that either suppress or control Capeweed. Be aware that you cannot use Envu Esplanade on turf grass areas.

Suppression of Capeweed.

• Pendimethalin (ProForce Battalia 435) suppresses the Cape Dandelion.

Control of Capeweed.

• Prodiamine – Syngenta Barricade or Spartan Herbicide
• Envu Esplanade Herbicide.
• Envu Specticle Herbicide.

Post Emergent Herbicides for Capeweed Control.

Several post-emergent herbicides are available for Capeweed such as Dicamba and MCPA. Once it is present in lawns, best control is to use herbicides that contain dicamba.

• You can kill young rosettes with MCPA or 2,4-D.
• ProForce Warhead Trio. This is safe to use on Buffalo grass.
• Weed Blast MA. This is safe to use on Buffalo grass.
• Casper Turf Herbicide. Don’t use Casper Turf Herbicide on Buffalo grass.
• ProForce Contra M. Don’t use Contra M on Buffalo grass.

Non Selective Control of Capeweed.

• Glufosinate-ammonium provides control for 4 to 6 weeks. Be aware that it will re-grow after this due to the limited movement of glufosinate.
• Glyphosate. You can use Glyphosate but if water quality is an issue then use ProForce Manta Ray.

The following are non-selective. They also have a long term residual effect and will stop re-growth of Cape Dandelion.

• Renegade. Renegade stops seed germination for up to 12 months. This reduces the need for multiple herbicide applications.
• Numchuk Quad. This gives effective post and pre emergent Capeweed control for up to 12 months.
• Cortex Duo. Cortex Duo gives a rapid knockdown of Cape Dandelion, and residual control for up to 3 months. It is also safe to use around trees.