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Purple Oxytropis

Oxytropis halleri

Please keep in mind that it is illegal to uproot a plant without the landowner's consent and care should be taken at all times not to damage wild plants. Wild plants should never be picked for pleasure and some plants are protected by law.
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Plant Profile

Flowering Months:
Fabaceae (Pea)
Also in this family:
Alpine Milk-vetch, Alsike Clover, Birdsfoot, Birdsfoot Clover, Bird's-foot Trefoil, Bithynian Vetch, Bitter Vetch, Black Broom, Black Medick, Bladder Senna, Broad Bean, Broad-leaved Everlasting Pea, Bur Medick, Burrowing Clover, Bush Vetch, Clustered Clover, Common Broom, Common Gorse, Common Laburnum, Common Restharrow, Common Vetch, Crimson Clover, Crown Vetch, Dragon's Teeth, Dwarf Gorse, Dyer's Greenweed, False Acacia, Fine-leaved Vetch, Fodder Vetch, Garden Lupin, Garden Pea, Goat's Rue, Grass Vetchling, Greater Bird's-foot Trefoil, Hairy Bird's-foot Trefoil, Hairy Greenweed, Hairy Tare, Hairy Vetchling, Hairy-fruited Broom, Haresfoot Clover, Hop Trefoil, Horseshoe Vetch, Hungarian Vetch, Kidney Vetch, Knotted Clover, Large Trefoil, Lesser Trefoil, Lucerne, Marsh Pea, Meadow Vetchling, Narrow-leaved Bird's-foot Trefoil, Narrow-leaved Everlasting Pea, Narrow-leaved Vetch, Nootka Lupin, Norfolk Everlasting Pea, Orange Birdsfoot, Petty Whin, Purple Milk-vetch, Red Clover, Reversed Clover, Ribbed Melilot, Rough Clover, Russell Lupin, Sainfoin, Scorpion Senna, Scottish Laburnum, Sea Clover, Sea Pea, Sickle Medick, Slender Bird's-foot Trefoil, Slender Tare, Slender Trefoil, Small Melilot, Small Restharrow, Smooth Tare, Spanish Broom, Spanish Gorse, Spiny Restharrow, Spotted Medick, Spring Vetch, Strawberry Clover, Suffocated Clover, Sulphur Clover, Tall Melilot, Toothed Medick, Tree Lupin, Tuberous Pea, Tufted Vetch, Twin-headed Clover, Two-flowered Everlasting Pea, Upright Clover, Upright Vetch, Western Clover, Western Gorse, White Broom, White Clover, White Lupin, White Melilot, Wild Liquorice, Wood Vetch, Yellow Oxytropis, Yellow Vetch, Yellow Vetchling, Zigzag Clover
Life Cycle:
Maximum Size:
30 centimetres tall
Grassland, mountains, rocky places, sand dunes, sea cliffs, seaside, woodland.

Purple, 5 petals
The flowers are purple fading to rosy-purple. White flowers are rare. The flowers appear in clover-like or pea-like clusters. Flowers measure up to 2cm in size.
Downy seed pods, up to 2cm in length.
A silky hairy perennial flower
Other Names:
Haller's Locoweed, Mountain Milk-Vetch, Purple Mountain Milk-Vetch, Silky Milk Vetch.
Frequency (UK):
Rarely seen  

Similar Species

Other Information


Oxytropis halleri is a species of flowering plant in the legume family, Fabaceae. It is native to the Rocky Mountains in North America and is commonly known as Haller's locoweed. The plant has small, purple flowers and can be found in rocky alpine meadows and open subalpine forests. Some populations of this plant are toxic to livestock, causing a disease known as locoism. It is a rare species and is protected in some areas.


Purple Oxytropis, also known as Oxytropis halleri, is a beautiful flowering plant native to the high altitudes of the Rocky Mountains and other mountainous regions of North America. This plant is a member of the pea family (Fabaceae) and is commonly referred to as Haller's oxytrope or Haller's locoweed.

Description and Characteristics

Purple Oxytropis is a herbaceous perennial plant that typically grows to a height of 6-12 inches (15-30 cm) and spreads up to 12-18 inches (30-45 cm) in diameter. It has a woody taproot and forms a compact, cushion-like structure of foliage. The leaves are green-gray, narrow, and elongated, growing to about 2-3 inches (5-8 cm) in length. The plant blooms from May to August and produces striking, purple-pink flowers that are about 1 inch (2.5 cm) long. The flowers are arranged in dense clusters at the top of short stalks.

Ecology and Habitat

Purple Oxytropis is commonly found in subalpine and alpine meadows, rocky slopes, and talus fields at high elevations of 7,000-14,000 feet (2,100-4,300 m) above sea level. The plant is adapted to harsh, cold, and windy environments and can tolerate extreme weather conditions. It is often found in areas where the soil is rocky, thin, and well-drained, and the growing season is short.

The plant is an important food source for bighorn sheep and mountain goats. However, the plant also contains alkaloids that are toxic to livestock and can cause serious health problems, such as locoism, a neurological disorder that affects the nervous system of grazing animals.

Conservation Status

Purple Oxytropis is not listed as a threatened or endangered species. However, like many high-elevation plants, it is vulnerable to the effects of climate change, habitat loss, and disturbance. The plant's delicate root system is easily damaged by human activities such as trampling, mining, and recreational activities.

Cultural Significance

Purple Oxytropis has cultural significance for indigenous communities in North America. The plant has been used in traditional medicine to treat a variety of ailments, including respiratory and digestive disorders. The roots of the plant were also used to create a black dye for leather and textiles.


Purple Oxytropis is a beautiful and unique plant that is adapted to harsh and extreme environments. While it is not listed as a threatened or endangered species, it is still vulnerable to the effects of climate change, habitat loss, and disturbance. Conservation efforts and sustainable land management practices are essential to ensure the survival of this important plant species for future generations.

More Information

Purple Oxytropis is a fascinating plant with many interesting features. One of the most notable characteristics of this plant is its ability to survive in extreme environments. The plant has adapted to the harsh conditions of the alpine tundra by developing a compact, cushion-like structure that helps it to conserve water and nutrients.

Another interesting feature of Purple Oxytropis is its relationship with bighorn sheep and mountain goats. These animals depend on the plant as a source of food, and the plant has evolved to be toxic to other herbivores, which helps to protect it from being overgrazed.

In addition to its ecological significance, Purple Oxytropis has cultural significance for many indigenous communities in North America. The plant has been used for centuries in traditional medicine, and its roots were also used to create a black dye for textiles and leather.

While Purple Oxytropis is not currently listed as a threatened or endangered species, it is still important to protect this plant and its habitat. Conservation efforts such as habitat restoration, land management practices, and education can help to ensure the survival of this unique and important plant for future generations.

Purple Oxytropis is also an important indicator species for the health of high-elevation ecosystems. As a plant that is sensitive to environmental changes, such as changes in temperature and moisture, it can provide valuable information about the impacts of climate change on these ecosystems. Monitoring the population and distribution of Purple Oxytropis can help scientists and land managers to better understand the health of alpine ecosystems and to develop effective conservation strategies.

Another interesting aspect of Purple Oxytropis is its use in ecological restoration. The plant is often used in restoration projects to help stabilize soil, prevent erosion, and restore disturbed areas. Its ability to grow in harsh conditions makes it a useful tool in restoring degraded alpine ecosystems.

Purple Oxytropis is a great example of the beauty and diversity of plant life in North America. Its striking, purple-pink flowers and unique adaptations make it a fascinating plant to observe and study. By learning about and appreciating plants like Purple Oxytropis, we can develop a deeper appreciation for the natural world and the important role that plants play in our lives.

Purple Oxytropis is also a valuable resource for scientific research. The plant contains a variety of compounds that have potential applications in medicine and other industries. For example, some of the alkaloids found in the plant have been shown to have antiviral and anticancer properties. Additionally, the plant has been used in traditional medicine to treat respiratory and digestive disorders, and research is ongoing to explore the potential medical applications of these traditional remedies.

The study of Purple Oxytropis and other high-elevation plants is also important for understanding the impacts of climate change on these ecosystems. As temperatures continue to rise, alpine plants like Purple Oxytropis are likely to experience changes in their distribution, flowering times, and other ecological processes. Studying these changes can help scientists to predict the impacts of climate change on other species and ecosystems.

Finally, the conservation of Purple Oxytropis and other high-elevation plants is important for preserving the unique biodiversity of these ecosystems. High-elevation ecosystems are home to a variety of unique and endangered species, and protecting these ecosystems is essential for maintaining the health of our planet.

In conclusion, Purple Oxytropis is a fascinating plant with many ecological, cultural, and scientific significance. As we continue to learn more about this species and its role in alpine ecosystems, it is important to work towards its conservation and the preservation of other high-elevation plants and ecosystems. By doing so, we can help to ensure a healthy and vibrant planet for generations to come.

Distribution Map

Reproduced by kind permission of the BSBI.

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