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Chalk Milkwort

Polygala calcarea

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Plant Profile

Flowering Months:
Polygalaceae (Milkwort)
Life Cycle:
Maximum Size:
15 centimetres tall
Grassland, rocky places.

Blue, 3 petals
The inflorescence is a short flower spike. It contains bright blue, tubular to bell-shaped flowers, each 6 to 8mm in size. Pale blue, white or pink flowers are occasional. White anthers.
The fruit is a capsule. Fruits are broader than the inner sepals.
A mat-forming evergreen perennial flower with leathery, oval, alternate leaves. Found on chalk and limestone turf.
Other Names:
Limestone Milkwort, Rock Milkwort.
Frequency (UK):

Similar Species

Other Information


Polygala calcarea is a species of flowering plant in the milkwort family, Polygalaceae. It is native to the Mediterranean region and is known for its small, pink or white flowers. The plant is also called "rock milkwort" or "limestone milkwort" due to its preference for growing in rocky or calcareous soils. The species is quite rare and endangered in nature.


Chalk Milkwort, also known as Polygala calcarea, is a flowering plant that is native to a few locations in Europe, including the UK. This plant is unique in that it is typically found in areas with chalky soils, and it is well-adapted to this environment. Here, we will take a closer look at Chalk Milkwort and explore some of its interesting features.

First and foremost, Chalk Milkwort is a relatively small plant, typically growing to be around 5-15cm in height. It is a perennial, which means that it can survive for multiple growing seasons, and it typically blooms from May to July. The flowers themselves are quite small, only around 5mm in size, and they are usually a shade of light blue or violet.

One of the interesting things about Chalk Milkwort is the way that it has adapted to the chalky soils in which it typically grows. These soils tend to be quite alkaline, which means that they have a high pH level. Chalk Milkwort is able to thrive in this environment because it has evolved to be tolerant of high pH levels, and it has also developed specialized roots that allow it to take in nutrients efficiently from the soil.

Another interesting feature of Chalk Milkwort is the fact that it has historically been used for medicinal purposes. In traditional medicine, the plant has been used to treat a variety of ailments, including respiratory problems, digestive issues, and skin conditions. While there is some scientific evidence to suggest that Chalk Milkwort may have some medicinal properties, further research is needed to fully understand its potential benefits.

In addition to its medicinal uses, Chalk Milkwort also has some cultural significance. In the UK, it is often associated with the chalk grasslands that are found in certain regions of the country. These grasslands are important habitats for a variety of plant and animal species, and they are also valued for their aesthetic beauty. Chalk Milkwort is just one of many species that can be found in these grasslands, and it is a valuable contributor to their overall biodiversity.

Chalk Milkwort is also interesting because it is a member of the Polygalaceae family, which includes over 900 species of plants. Within this family, Chalk Milkwort is part of the section Polygala, which includes many other species of milkworts. One of the key features of this section is the presence of specialized structures called "honeyguides" on the flowers. These structures are thought to help guide pollinators to the flower's nectar and pollen.

Chalk Milkwort is primarily pollinated by bees and flies, which are attracted to its flowers by their bright colors and sweet scent. The plant produces both nectar and pollen, which provide a valuable source of food for these insects.

In addition to its ecological and cultural significance, Chalk Milkwort is also a popular ornamental plant. It is sometimes grown in gardens and other landscaped areas, where it can add a splash of color and interest to the landscape. However, because it is a relatively delicate plant, it requires careful cultivation and may not be well-suited to all growing conditions.

Chalk Milkwort is a fascinating and unique plant that offers many insights into the natural world. Whether you are interested in its ecological importance, its cultural significance, or its potential medicinal uses, there is much to discover about this humble little flower. So next time you come across a patch of Chalk Milkwort growing in the wild, take a moment to appreciate its beauty and its many contributions to the world around us.

Chalk Milkwort is also an important indicator species for conservation efforts. Because it is well-adapted to the chalky soils found in certain regions of Europe, its presence can be used as an indicator of the overall health and biodiversity of these ecosystems. When Chalk Milkwort is present, it is a sign that the soil is relatively undisturbed and that other important plant and animal species are likely to be thriving as well.

Unfortunately, like many other plant species, Chalk Milkwort is under threat from habitat loss and fragmentation. In recent years, the amount of chalk grassland in the UK and other parts of Europe has declined significantly, due to factors like agricultural intensification, urbanization, and land-use changes. This has had a negative impact on the populations of many species, including Chalk Milkwort.

Conservation efforts are underway to protect and restore chalk grasslands, and these efforts may help to ensure the survival of Chalk Milkwort and other important species. For example, some organizations are working to establish new grasslands and to restore degraded areas, in order to create new habitats for these plants and animals.

One interesting aspect of Chalk Milkwort is its relationship with other plant species in the chalk grassland ecosystem. Because these grasslands are home to a variety of different plant species, Chalk Milkwort must compete with other plants for resources like water, nutrients, and sunlight. However, it has evolved to be particularly well-adapted to this competitive environment, and it is able to thrive even in the face of intense competition from other plants.

Another important factor in the survival of Chalk Milkwort is its ability to tolerate environmental stressors like drought and nutrient-poor soils. Because it is adapted to chalky soils, which tend to be relatively low in nutrients and water, the plant is able to survive even in harsh conditions. This resilience is an important asset in a world where climate change and other environmental pressures are making it increasingly difficult for many plant species to survive.

Despite its small size, Chalk Milkwort is a species with a big impact on the ecosystems in which it is found. From its contributions to biodiversity and ecosystem health to its cultural and medicinal significance, this little plant has much to offer. Whether you are a scientist, a nature lover, or simply someone who appreciates the beauty of the natural world, there is something to be gained from taking a closer look at Chalk Milkwort and the many wonders it has to offer.

Distribution Map

Reproduced by kind permission of the BSBI.

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