Origin
Lupinus arcticus S. Wats. ssp. subalpinus (Piper & B.L. Robins.) D. Dunn, commonly known as Subalpine Lupine, is a flowering plant native to North America. It can be found growing in subalpine and alpine regions across western North America, including parts of Alaska, British Columbia, and the western United States.
Common Names
Subalpine Lupine is also known by several other common names, including Arctic Lupine, Sickle-Keel Lupine, and Alpine Lupine.
Uses
Subalpine Lupine has several uses, both traditionally and in modern times. Indigenous communities have used it for food and medicinal purposes, while it is also valued as a garden ornamental for its showy blooms. Additionally, it has gained attention as a potential tool for ecological restoration due to its ability to fix nitrogen in soil and improve soil health.
General Appearance
Subalpine Lupine is a perennial herbaceous plant that grows between 10 to 80 centimeters tall. It has a taproot system and a branching stem covered in dense silver-green hairs. Its leaves are palmately compound and consist of 5 to 9 leaflets that are narrowly oblanceolate or linear in shape. The plant blooms in the summer months, producing tall spikes of showy blue or purple flowers that are occasionally white or pink. The fruit is a legume containing several seeds.
Light Requirements
Lupinus arcticus S. Wats. ssp. subalpinus prefers full sun to partial shade and tolerates light shade. It grows well in open meadows and along forest edges where it can receive adequate sunlight.
Temperature Requirements
The typical range for Lupinus arcticus S. Wats. ssp. subalpinus is from subalpine to alpine areas. It usually grows in areas with cool temperatures, and temperatures above 23°C can be detrimental to its growth. In the summer months, it can tolerate temperatures up to 18°C.
Soil Requirements
Lupinus arcticus S. Wats. ssp. subalpinus prefers well-drained soils that are moist, but not waterlogged. It can grow in a variety of soil types ranging from sandy loams to clay loams. The plant will grow in soils that are acidic to slightly basic, with a pH range of approximately 5.0 to 7.5. Additionally, this plant is adapted to nutrient-poor soil conditions, including those with low levels of nitrogen and phosphorus.
Cultivation methods
Lupinus arcticus ssp. subalpinus is a hardy plant that grows best in well-drained soils and full sun. It is important to choose a planting site that receives at least six hours of direct sunlight each day. Before planting, amend the soil with some organic matter to improve its water-holding capacity and nutrient content.
Seeds should be planted in early spring or late summer while the soil is still warm. Sow the seeds about 1/4 inch deep and 6 inches apart. Keep the soil moist until the seeds germinate, which typically takes between 7 and 21 days. Once the plants reach a height of 1 inch, thin them out to a spacing of 12 inches apart.
Watering needs
Lupinus arcticus ssp. subalpinus prefers moist, well-drained soil. During the growing season, water deeply once or twice a week, depending on the amount of rainfall. Avoid over-watering, which can lead to root rot and other diseases.
In areas with hot, dry summers, it may be necessary to water more frequently to keep the plants from wilting. When watering, aim to wet the soil to a depth of at least 6 inches.
Fertilization
Lupinus arcticus ssp. subalpinus does not require much fertilizer. A light application of a balanced, slow-release fertilizer in the spring can help promote healthy growth and flowering. Follow the package instructions carefully, as over-fertilizing can harm the plant.
Avoid applying fertilizer in the fall, as this can cause the plant to produce new growth that may be damaged by winter frosts.
Pruning
Lupinus arcticus ssp. subalpinus does not require much pruning, but deadheading spent blooms can help prolong the flowering period. Simply snip off the faded flowers as soon as they wilt.
In the fall, after the plant has finished flowering, it is a good idea to cut back the stems to within a few inches of the ground. This will help prevent the plant from becoming too woody and encourage it to produce new growth in the spring.
Propagation of Lupinus arcticus S. Wats. ssp. subalpinus (Piper & B.L. Robins.) D. Dunn
Lupinus arcticus S. Wats. ssp. subalpinus (Piper & B.L. Robins.) D. Dunn is typically propagated through seed. The seeds of the plant can be collected in late summer or early autumn once they have fully matured. Once collected, the seeds should be stored in a cool, dry place until they are ready to be planted.
Seed Propagation
Before planting, it is important to scarify the seeds by either nicking them with a knife or rubbing them with sandpaper. This process helps to break down the seed coat and improve germination rates. Once scarified, the seeds should be soaked in water for 24 hours.
The seeds should then be planted in the desired location during the fall or early spring. It is important to plant the seeds in a location with well-draining soil and full sun. The seeds can be planted directly into the soil or started indoors in biodegradable pots filled with potting soil.
Once planted, the seeds should be watered regularly to keep the soil moist. Germination typically occurs within two to three weeks, and the seedlings should be thinned to 6 inches apart after they have grown to around 3 inches in height.
Disease and Pest Management for Lupinus arcticus S. Wats. ssp. subalpinus
Lupinus arcticus ssp. subalpinus is a beautiful plant that can be grown in gardens and landscapes. Despite its attractiveness, this plant can be prone to many diseases and pest attacks. Here are some common diseases and pests that can affect this plant and ways to manage them:
Diseases
Root rot is a common disease of Lupinus arcticus ssp. subalpinus. The disease is usually caused by soil-borne fungal pathogens such as Phytophthora and Rhizoctonia. The plants affected by root rot become stunted and may yellow and wilt. The best way to manage root rot is by planting the plant in well-draining soil. Watering should also be done in moderation, especially during the rainy season. Fungicide treatment may also help to control the disease in its early stages.
Another common disease that can affect Lupinus arcticus ssp. subalpinus is powdery mildew. This fungal disease attacks the leaves and stems of the plant, leaving them with a powdery white or gray coating. The plant may also become stunted and weakened. The best way to manage powdery mildew is by removing the affected parts of the plant and practicing good sanitation practices. Fungicide treatment may also help to control the disease.
Pests
Lupinus arcticus ssp. subalpinus can also be affected by various pests such as aphids, slugs, and snails. Aphids usually attack the leaves and stems of the plant, sucking the sap and causing damage. The best way to manage aphids is by removing them manually or using insecticidal soap. Slugs and snails feed on the leaves of the plant, leaving large holes and damaging the plant. The best way to manage slugs and snails is by removing them manually or using snail and slug bait.
Additionally, spider mites can also infest Lupinus arcticus ssp. subalpinus. These pests suck the sap from the leaves, causing them to turn yellow and fall off. The best way to manage spider mites is by washing the plant with a strong jet of water or using insecticidal soap.
In conclusion, effective disease and pest management strategies can help to keep your Lupinus arcticus ssp. subalpinus healthy and thriving. Proper cultural practices such as planting in well-draining soil, watering in moderation, and good sanitation practices can help to prevent the onset of diseases and pest attacks.
