Cow herb: planting, care & propagation

Cow herb, also known as cow cockle, is an easy-care annual with delicate, pink flowers. It makes a wonderful addition to cottage gardens and can even be used as cut flowers.

Cow herb (Vaccaria hispanica) is an extremely undemanding plant with beautiful flowers that butterflies and moths also enjoy. Read on to find out how to plant and care for cow herb.

Cow herb: origin and characteristics

Cow herb (Vaccaria hispanica), also known as cow basil or cow cockle, originates from the Mediterranean and Asia. It has been common in large parts of Europe and Asia for over 1000 years, but has also been introduced to America, Australia and South Africa via seeds. Cow herb belongs to the plant genus known as Gypsophila and is mostly found on calcareous, stony fields, where it grows as a field weed. It is even considered an indicator plant for dry and calcareous soils.

Cow cockle is a winter annual, meaning the seeds germinate as early as autumn, when low temperatures and darkness promote germination. In spends the following spring growing and then flowers in the summer. In our part of the world, cow herb flowers from July to August or September. It forms small, pink flowers that sit in a blistered calyx tube. Occasionally, you will find white-flowering varieties. Cow herb leaves have smooth edges and grow opposite along the stem. Both the stem and foliage are grey-green in colour. This herbaceous plant grows to about 70cm, sometimes even up to 1m tall.

Cow cockle plants are popular with bees and especially butterflies. Due to their rather late flowering time, they sometimes provide pollinators with nectar until early autumn. Cow herb is also ideal for black box gardening, which is where plants are left to do their own thing and find their own way in the garden.

Tip: Because of the saponins it contains, cow herb is slightly poisonous, especially to fish and other aquatic animals. Nevertheless, it is used for medicinal purposes in China, and in some countries it is also used in cooking.

The most beautiful varieties of cow herb

There are two main varieties of cow herb. There are also several other cultivated forms, but they are mainly found in North America.

• Vaccaria hispanica ‘Pink Beauty’: this variety has small, pink flowers and looks very similar to the wild form.
• Vaccaria hispanica ‘White Beauty’: cow herb ‘White Beauty’ is a white-flowering variety that was bred in Great Britain.

Planting cow herb: where, when & how

Cow herb is an ornamental plant that goes well in both fields and gardens. When planting cow herb in your garden, opt for a bright location. These plants like it sunny and warm and also prefer well-drained soil. They grow both on stony ground and on loam. Cow herb needs plenty of nutrients and a moderate amount of nitrogen. To improve the soil, work in some high-quality substrate, such as our Plantura Organic All Purpose Compost. This compost contains all the key nutrients cow herb needs and is also safe for garden wildlife and pets. When planting in pots, mix in about a third of sand to improve drainage. As cow herb prefers calcareous soil, it is a good idea to lime the soil before sowing.

How to sow cow herb: Sow directly into the bed in autumn. Before sowing, loosen the soil. Leave a sowing distance of about 20cm between the individual plants. Cow herb needs light to germinate, so do not cover the seeds with any soil. Simply press the seeds down lightly to prevent them from blowing away. You can also grow the seeds on a windowsill between March and April at 20°C, but as the cold promotes germination, it is likely that not all seeds will germinate. Therefore, the rule of thumb is to sow three to five seeds in a 9cm pot.

Cow herb care

Cow herb is a very low maintenance plant. Depending on its location, a few adjustments may be necessary.

Cow cockle does well in dry soil, but will benefit from the occasional bit of water in prolonged periods of drought in summer.

If planting cow herb in nutrient-poor garden soil, fertilise once with a slow-release fertiliser when sowing. Our Plantura All Purpose Plant Food is suitable for this, as the nutrients it contains are released to the plant gradually over a period of at least three months. There is no need to top up during this time. Our all purpose fertiliser also consists of ingredients that are permitted in organic farming and promotes an active and healthy soil life.

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You do not need to prune cow herb. However, should the bed become too crowded, Vaccaria hispanica also makes a beautiful cut flower in a vase. As cow herb is an annual, there is usually no need to take precautions for the winter either. Since cow herb seeds are sown in winter, only the seedlings have to survive the winter. The small seedlings can withstand temperatures of down to -10°C without any problems. That said, if the winter is a particularly harsh one, protect the seedlings by mulching with a layer of leaves or bark.

Propagation

Cow herb is propagated by seeds. You can either buy cow herb seeds at your local garden centre or online, or obtain some from your own plants. To do this, harvest the ripe seed capsules surrounded by the green bracts in late summer and autumn and plant them in the desired spot in your garden. Alternatively, you can leave cow herb to propagate itself, as the plant reproduces by self-seeding.

Since the common poppy (Papaver rhoeas) also grows on arable land, it is an excellent plant to grow together with cow herb in a bed. Find out what to bear in mind when planting and caring for poppies.