Overview of Lupinus argenteus Pursh ssp. ingratus (Greene) Harmon
Lupinus argenteus Pursh ssp. ingratus (Greene) Harmon, commonly known as Silvery lupine, is a herbaceous perennial plant that belongs to the Fabaceae family. It is native to western North America and can be found from British Columbia to Southern California. The plant has deep roots that can tap water from beneath the soil, making it a useful plant for erosion control and revegetation of disturbed sites.
Appearance
Silvery lupine is a tall and showy plant that can grow up to three feet tall. The plant has a single stem that blooms with a tall spike of blue to purple flowers from May to August. The flowers are arranged in a cone-like shape, with each flower being about half an inch long. The leaves are palmately compound with five to nine leaflets, with each leaflet being about an inch long. The plant has a silvery-gray coloration that gives it its common name.
Common Uses
Silvery lupine has several uses, including:
- Ecological: Silvery lupine is an important plant in Western prairies and savannas, where it provides food for grazing animals like deer and elk.
- Erosion control: The plant’s deep roots make it useful for controlling soil erosion on slopes and other disturbed sites.
- Revegetation: Silvery lupine is used in land restoration projects to revegetate sites damaged by wildfires, logging, and other disturbances.
- Horticulture: The plant is also grown as an ornamental plant in gardens and parks. Its tall spikes of blue to purple flowers make it a showy addition to any landscape.
In conclusion, Silvery lupine is a beautiful and useful plant that is native to the western part of North America. Its showy purple-blue flowers, silvery leaves, and deep roots make it an excellent plant for horticulture, ecological restoration, and erosion control purposes.
Light Requirements
Lupinus argenteus Pursh ssp. ingratus (Greene) Harmon typically grows in areas with full sun exposure. Thus, it is recommended that the plant receives at least six hours of sunlight daily. Insufficient light can affect the flowering and growth of the plant, causing the stems to elongate as it tries to reach for more sunlight.
Temperature Requirements
The plant is native to the western regions of North America, where it typically grows in areas with hot summers and cold winters. Lupinus argenteus Pursh ssp. ingratus (Greene) Harmon can survive in temperatures up to 90°F during the summers, but it requires cooler temperatures during winter months to germinate. The plant can tolerate frost and even snow during the winter months, but too much exposure to very cold weather can affect its growth.
Soil Requirements
The plant can grow in various soil types, but it prefers well-draining soils with pH levels ranging between 6.0-7.5. The plant can also grow in rocky soils and steep slopes, but it requires moderate moisture levels to thrive. Overly wet soils can lead to root rot, which can eventually kill the plant. Additionally, the plant needs relatively low nutrients and organic matter in the soil; too much of these can lead to excessive vegetative growth and reduced flower production.
Cultivation Methods
Lupinus argenteus Pursh ssp. ingratus (Greene) Harmon, commonly known as Silver Lupine, is a perennial plant native to the western United States. It grows well in well-drained soils and in full sun to partial shade. The plant thrives in USDA hardiness zones 3 to 8.
The plant prefers dry to medium moisture levels and does not tolerate standing water or soggy soil. It is best to plant during the spring or fall when the temperatures are milder and rainfall is more frequent. When planting, provide ample spacing of about two to three feet between each plant to allow for air circulation.
Watering Needs
Watering is essential for lupine plants, especially during the growing season. Silver Lupine plants require moderate watering, about 1 inch of water weekly. The best time to water is in the early morning or late evening when the temperatures are cooler.
Overwatering could lead to root rot, while under watering could cause wilting. Mulching the soil around the plant helps retain moisture and prevent water loss. Avoid watering the plant's foliage and, instead, direct the water to the root zone to prevent the formation of fungal diseases.
Fertilization
Lupine plants are moderate feeders, and they require fertile soils to thrive. Incorporate organic matter such as compost or well-rotted manure when planting, which provides the plant with nutrients to grow.
During the growing season, apply a balanced liquid fertilizer every four weeks to keep the plant well-fed. Avoid fertilizing the plant during winter when it is dormant.
Pruning
Lupine plants do not require extensive pruning. Deadhead the plant regularly, especially after blooming to encourage more flowers and prevent self-seeding.
However, if you prefer to prevent the plant from spreading, you can cut off the spent flower stems before the seeds mature. You can also remove the entire plant after flowering in late spring, and the next generation of plants will emerge from the mature seeds dropped during the growing season.
Propagation of Lupinus argenteus Pursh ssp. ingratus (Greene) Harmon
Propagation of Lupinus argenteus Pursh ssp. ingratus can be accomplished through several methods. The plant can be propagated by seed, cuttings, or division.
Propagation by Seed
Propagation by seed is the most common method used to propagate Lupinus argenteus Pursh ssp. ingratus. Seeds should be collected in the fall after the pods have matured and turned brown. Once collected, the seeds should be stored in a cool, dry place until planting. The seeds should be scarified and then soaked in hot water for several hours before planting to help break down the hard seed coat and improve germination rates. Seeds should be planted in early spring in a sunny location with well-draining soil.
Propagation by Cuttings
Propagation by cuttings is another method used to propagate Lupinus argenteus Pursh ssp. ingratus, but it is less common. Cuttings should be taken in early summer from young, vigorous plants. Cuttings should be taken from the new growth and should be approximately 4-6 inches long. The cuttings should be dipped in rooting hormone and planted in a well-draining soil mix. The cuttings should be kept in a warm and humid environment until they have developed roots and can be transplanted to a more permanent location.
Propagation by Division
Propagation by division is the easiest method to propagate Lupinus argenteus Pursh ssp. ingratus. The plant can be divided in the early spring before new growth begins or in the fall after the plant has finished blooming. The root ball should be dug up and carefully separated into several smaller sections, making sure that each section has roots attached to it. Each section should be replanted in a location with well-draining soil and plenty of sunlight.
Disease Management
There are several diseases that can affect Lupinus argenteus Pursh ssp. ingratus, including powdery mildew, rust, and fungal leaf spots.
To manage powdery mildew, avoid overhead irrigation, improve air circulation, and remove infected leaves and plant debris. Fungicides may also be used as a last resort.
Rust can be managed by removing infected plant debris, providing good air circulation, and avoiding overhead irrigation. Fungicides may also be used if necessary.
Fungal leaf spot can be managed by removing infected leaves and plant debris and providing good air circulation. Fungicides may also be used if necessary.
Pest Management
Lupinus argenteus Pursh ssp. ingratus can be affected by several pests, including aphids, spider mites, and slugs.
To manage aphids, introduce natural predators such as ladybugs or lacewings, or wash plants with a strong stream of water. In severe cases, insecticidal soap or neem oil may be used.
Spider mites can be managed by spraying plants with a strong stream of water or introducing natural predators such as predatory mites. In severe cases, horticultural oil or insecticidal soap may be used.
Slugs can be managed by manually removing them from the plant and surrounding area, or by using slug baits or traps. Copper barriers can also be effective in keeping slugs away from plants.
