Origin and Common Names
Lupinus polyphyllus Lindl. var. saxosus (T.J. Howell) Barneby, commonly known as big-leaved lupine or saxatile lupine, is a herbaceous perennial plant that belongs to the Fabaceae family. The plant is native to the western regions of North America, such as Oregon, Washington, British Columbia, and Alaska.
General Appearance
The plant has a bushy appearance with a height of 3-4 feet and a width of 2-3 feet. Saxatile lupine produces beautiful blue-violet flowers that grow on tall spikes, typically blooming from May to July. The foliage of this plant consists of large leaves, with a distinctive palmate shape that forms a rosette at the base. The leaves are typically 8-10 inches in length, and the entire plant is covered in silky hair.
Uses
Saxatile lupine is a popular plant for gardens, parks, and landscaping. It adds a beautiful pop of color to an outdoor space, and its tall spikes can bring a sense of structure to a garden. Additionally, the plant is used in ecological restoration projects to restore natural habitats or create new ones. One of the reasons for its popularity is that saxatile lupine is a nitrogen-fixing plant, which means it can help restore nutrient-deprived soil. This makes it an essential plant for restoring habitats and bringing life to areas that have been manipulated by humans.
Overall, saxatile lupine is a gorgeous and beneficial plant that can add beauty and ecological value to any outdoor space.Light Requirements
Lupinus polyphyllus Lindl. var. saxosus (T.J. Howell) Barneby favors full sun to partial shade for optimal growth. In areas with intense summers, partial shade may be preferable to prevent the plant from experiencing heat stress. The plant will not do well in complete shade and will not likely flower.
Temperature Requirements
The plant is capable of growing in a range of temperatures, depending on the location. In areas with colder temperatures, the plant can handle temperatures as low as -15°C. In warmer locations, the plant will grow better with temperatures between 15°C and 25°C. Hotter temperatures will cause the plant to become stressed, and the soil should be kept moist to prevent the plant from wilting too quickly.
Soil Requirements
Lupinus polyphyllus Lindl. var. saxosus (T.J. Howell) Barneby prefers slightly acidic to slightly basic soil, between pH 6 and pH 7.5. The soil must be well-drained to prevent any waterlogging and maintain healthy roots. The plant does well in sandy and loamy soils. However, heavy soils will need to be amended with sand, organic matter, or compost to increase the soil's drainage capacity and prevent the plant's roots from rotting.
Cultivation Method
Lupinus polyphyllus Lindl. var. saxosus (T.J. Howell) Barneby, or the bigleaf lupine, is a hardy perennial plant that is easy to grow. It can be propagated from seed or cuttings and prefers well-draining soil that is rich in organic matter. The plant needs to be placed in an area with full sunlight to produce a good crop. Lupines can tolerate cold temperatures and are hardy in USDA zones 3-7. It is best to plant them in early spring or in fall.
Watering Needs
When it comes to watering Lupinus polyphyllus Lindl. var. saxosus, it is important to provide consistent moisture levels. Overwatering causes the plant's roots to rot, while underwatering will lead to poor growth. During hot weather, lupines should be watered every day to maintain soil moisture levels. These plants also benefit from occasional misting to increase humidity levels.
Fertilization
Lupinus polyphyllus Lindl. var. saxosus thrives in soil that is rich in nutrients, and therefore needs to be fertilized regularly. Fertilizers high in phosphorus promote flowering, while potassium helps to strengthen roots. Nitrogen is also essential for leaf growth. The application of a balanced fertilizer every four weeks will ensure that the plant receives the necessary nutrients to grow and flower. It is important to follow the manufacturer's instructions to prevent overfertilization, which can lead to damage to the roots or foliage.
Pruning
Pruning Lupinus polyphyllus Lindl. var. saxosus is not necessary as it grows naturally and maintains its shape. However, removing spent flowers will encourage new growth and promote continued blooming throughout the season. To encourage flowering in the following year, the plant's stems should be cut back to the ground after the first frost. This will help the plant conserve energy, allowing it to produce a better crop the following year. It is also important to remove any dead or damaged leaves to keep the plant looking tidy and to prevent the spread of diseases.
Propagation of Lupinus polyphyllus Lindl. var. saxosus (T.J. Howell) Barneby
Lupinus polyphyllus Lindl. var. saxosus (T.J. Howell) Barneby, commonly known as the Big Leaf Lupine, is a herbaceous perennial plant that is native to North America. It is a hardy plant that can grow in a variety of soil types, and it is a popular plant amongst gardeners due to its beautiful, showy flowers that come in shades of blue, purple, pink, and white. The plant is propagated through various methods, including seed propagation, division, and stem cuttings.
Seed Propagation
The most common method of propagating Lupinus polyphyllus Lindl. var. saxosus is through seeds. The seeds are readily available and can be purchased from seed suppliers or harvested from mature plants. The seeds are sown in the soil in early spring or fall, depending on the climatic conditions. They should be sown about 1/2 inch deep in well-draining soil and covered lightly with soil. Water the soil regularly, and the seeds will germinate in about 10-14 days, depending on the temperature. Once the seedlings are large enough to handle, they can be transplanted to their permanent position.
Division
Division is another method of propagating Lupinus polyphyllus Lindl. var. saxosus. The plant can be divided into smaller segments during the spring or fall when the plant is dormant. Carefully dig up the plant, and then use a sharp knife or spade to cut the plant into smaller sections. Each section should have a healthy root system and some shoots. Replant the divided sections in well-draining soil, water the soil, and keep them in a shady area for a few days until they become established.
Stem Cuttings
Stem cuttings are also a viable method for propagating Lupinus polyphyllus Lindl. var. saxosus. Take cutting from the stem tips of the plant in early summer, making sure that each cutting is about four inches long and has at least two leaves. Trim the bottom of the cutting, and then dip it in rooting hormone powder. Insert the cutting into a well-draining potting mix, water the soil, and place it in a shaded area. Keep the soil moist, and in about two to three weeks, the cutting should have developed enough roots to be transplanted into its permanent position.
Disease Management
Lupinus polyphyllus Lindl. var. saxosus is susceptible to several diseases, including powdery mildew, leaf spots, and root rots.
Powdery Mildew: This disease appears as a white, powdery substance on the plant's leaves, stems, and flowers. To manage this disease, avoid overhead watering, provide good air circulation, and remove and destroy infected plant parts. Fungicidal sprays can also be used, but should be applied according to label directions.
Leaf Spots: Several fungal diseases can cause leaf spots on lupines. These spots range in appearance and size, but in general appear as brownish areas on the leaves. Management involves removing and destroying infected plant parts, improving air circulation around the plant, and avoiding overhead watering. Fungicidal sprays may also be used, but prevention is the best management strategy.
Root Rots: Several fungal pathogens can cause root rot in lupines, which can lead to wilting and plant death. To manage root rots, avoid overwatering or poor drainage, improve soil fertility and structure, and avoid planting in areas with a history of root rot problems. Fungicidal drenches may also be used, but only after proper diagnosis of the disease.
Pest Management
Lupinus polyphyllus Lindl. var. saxosus is not highly prone to insect infestations, but several pests may still affect the plant.
Aphids: These tiny insects can gather on the undersides of lupine leaves, causing plant damage and a sticky substance known as honeydew. Management options include washing off the aphids with a strong stream of water, using insecticidal soaps, and encouraging natural predators such as ladybugs.
Spider Mites: These tiny pests can cause stippling, yellowing, and leaf drop on lupine plants. Management options include washing off the mites with a strong stream of water, using insecticidal soaps, and encouraging natural predators such as predatory mites.
Cutworms: These caterpillars can sever young lupine plants at the stem, causing plant death. Management options include handpicking the caterpillars, using beneficial nematodes, and applying insecticidal sprays containing Bacillus thuringiensis (Bt).
