10 Tips to recognize Jacobaea vulgaris 

To prevent Jacobaea vulgaris in the feed of cattle and horses, it is important to recognize the plant and distinguish it from other yellow flowering plants. 

RIKILT, part of Wageningen UR, has developed a program that identifies yellow flowering plants by giving answers to a number of questions. The program also allows plants to be compared, and can be scrolled through the descriptions and photos. Visit the Rikilt website to download the computer program.

Determination

Do you want to have Jacobaea vulgaris in your pasture or do you want to recognize the plant better? By identifying all parts of the plant you can check if you are dealing with this poisonous herb or that it may be a different plant. 

General

In the first year, the plant forms an unobtrusive rosette, which often causes young plants to be overlooked. In the second year most plants bloom, put seeds and die. The stem of Jacobaea vulgaris is usually a little purple in color. The “kale-like” lobed leaves are dark green and at the bottom are a bit witty in color. Where the plant does not bleed (e.g., by mowing or grazing), the plants are present in the vegetation as rosette. 

Leaves

The shape of the leaf can be elongated (left), oval (center) and round (right). The leaves of Jacobaea vulgaris and some relatives have an oval leaf blade along the outer edge, as seen in the second leaf (middle). 

Number of leaves

The number of leaves of is one, as shown in the first example (left). The picture shows a view of three leaves (middle) per leaf and a lot of leaves per leaf (right). 

Edge of the leaf disc or the leaves 

The edge of the leaf disc or of the leaves can be described as follows: 

• Smooth, including toothed, sawn, corrugated (left) 
• Cutted, including lobed, feathery (middle) 
• Suspended, single or double-veered (right) 

Jacobaea vulgaris and some related species have single or double-leaf leaves.

Degree of incision of the leaf edge 

Jacobaea vulgaris has a double cut of the leaf edge, as shown in the first example (left). The right example shows a single cut of the leaf edge. 

Leaves‘ hair 

The leaves of Jacobaea vulgaris are not hairy. An example of this is shown in the left image. The example at the top right shows an example of a leaf that is not hairy and the lower right example gives an example of a sheet that is hairy. 

Whole plant 

The stem of Jacobaea vulgaris is tough and often has a red discoloration at the bottom. The plant flourishes from June to October and is between 30 and 100 cm high. 

Opposite leaves 

Jacobaea vulgaris has spread standing leaves, as in the left-hand view. The right example shows a view of opposite leaves. 

Placement of the leaves 

Jacobaea vulgaris also rises as a young plant, which disappears at a later stage. The plant can thus have roseblade with stalk leaves or stalk leaves. The top example shows a roseblade display and the lower example shows a view of stem leaves 

Flowers

Farmer’s worm and Jacobaea vulgaris are quickly confused. The flowers are clearly different. 

Jacobaea vulgaris                                           Boerenwormkruid

     

Spreading of the flowers 

The flower heads that are attached to one stem have flower stems of different length so that the flower heads together form a screen (official term: tuil, see lower example). The top example shows irregularly distributed flowers. 

Flower heart

The flowers of Jacobaea vulgaris have a flower heart, as can be seen in the left picture. The right example shows a flower without flower heart. 

Number of petals 

The flowers of Jacobaea vulgaris have petals. The left preview shows no petals. The middle example shows four petals and the right example gives a view of several petals. 

Flower color 

Jacobaea vulgaris has a dark colored flower, as shown in the right example. However, the flower color depends on the location.  

Healthy roughage 

Hartog’s healthy roughage is produced through controlled crops, making the products free from weeds, such as the poisonous Jacobaea vulgaris. After mowing the grass and / or luzerne are chopped and dried in a large drying drum at very high temperatures. Rapid drying keeps the freshness and taste of the product. Also, all bacteria, fungi and germs are destroyed, which makes our Lucerne-mix, Gras-mix and Compact Grass a definite added value to traditional roughage feeders, such as hay and (fore dry) grass.