Origin and Common Names
Lupinus nanus Dougl. ex Benth. var. maritimus Hoover, commonly known as coastal lupine, is a subspecies of the Lupinus genus in the Fabaceae family. It is native to the Pacific coast of North America, from southern Alaska to California. Coastal lupine prefers to grow in sandy or gravelly soils, such as coastal bluffs, dunes, and scrub habitats.
Appearance
Coastal lupine is a low-growing, herbaceous perennial that can reach up to 18 inches tall. It has blue-green, palmately compound leaves with 5-7 leaflets that are oval in shape and hairy to the touch. The plant produces brightly colored, showy flowers in tall, dense spikes that can range from blue, purple, pink, or white. The flowers have a distinctive pea-like shape, with a banner, wings, and keel that enclose the reproductive organs.
Uses
Coastal lupine has many uses in horticulture, especially in garden design and landscaping. It is valued for its showy flowers, drought tolerance, and ability to attract pollinators like bees and butterflies. Coastal lupine is also important in the ecology of its native range, as it is a host plant for the larvae of various butterfly species, including the endangered Mission Blue Butterfly (Icaricia icarioides missionensis).
Light Requirements
Lupinus nanus Dougl. ex Benth. var. maritimus Hoover requires plenty of sunlight to grow and thrive. It is recommended to place the plant in an area where it can receive direct sunlight for at least 6 hours a day. However, the plant can also tolerate partial shade, but flowering may not be as prolific as those grown in full sun.
Temperature Requirements
The plant prefers cool temperatures and grows well in USDA hardiness zones 8 to 10. The optimal temperature range for growth is between 60°F to 70°F. It is important to note that Lupinus nanus Dougl. ex Benth. var. maritimus Hoover is not frost-tolerant, so it is crucial to protect the plant during cold weather conditions.
Soil Requirements
Lupinus nanus Dougl. ex Benth. var. maritimus Hoover thrives in well-draining soils that are slightly acidic with a pH range of 4.5 to 6.5. The plant does not tolerate waterlogged soils, so it is essential to ensure good drainage. It is also recommended to mix in some organic matter, such as compost or peat moss, to improve soil texture and fertility. Additionally, the plant prefers soils that are rich in phosphorus, so a phosphorous-rich fertilizer can be beneficial for growth and flowering.
Cultivation methods
Lupinus nanus Dougl. ex Benth. var. maritimus Hoover, commonly known as the seaside lupine, thrives in sunny locations and well-drained soils. It is a tough and hardy plant, adapting to a wide range of soil types, from clay to sandy loams.
Seaside lupines grow best in areas with mild temperatures that do not exceed 75°F. They can also withstand salty ocean breezes and coastal winds. It is recommended to sow seeds directly outdoors in the fall or early winter.
Before planting, remove any weeds and break up the soil surface. Press the seeds lightly into the soil to ensure good seed-to-soil contact. Water the area and keep the soil evenly moist during the germination period.
Watering needs
Lupinus nanus Dougl. ex Benth. var. maritimus Hoover requires regular watering, especially during the germination phase. Once established, it can tolerate drought conditions but still requires some watering to produce the best blooms.
Make sure that the soil is evenly moist, but not waterlogged, to avoid root rot. Watering the plant in the morning is advisable as it allows the leaves to dry out during the day, reducing the risk of fungal diseases.
Fertilization
The seaside lupine does not require heavy fertilization, and in fact, excess fertilizer can stunt growth or cause the plant to produce more foliage than flowers. Nitrogen-rich fertilizers should be avoided, as they can affect flowering negatively.
One application of compost at the beginning of the growing season can supply the plant with sufficient nutrients. Alternatively, a balanced fertilizer can be applied once a month during the growing season. Always follow the instructions on the fertilizer package, applying slightly less than recommended if the soil is already rich in nutrients.
Pruning
The seaside lupine tends to produce only one stem and does not require regular pruning. However, deadheading faded blooms can encourage more flowers to grow. It is recommended to cut off the entire stem of the plant after the flowering period, as this will ensure that the plant remains healthy and compact for the following season.
Propagation of Lupinus nanus Dougl. ex Benth. var. maritimus Hoover
Lupinus nanus Dougl. ex Benth. var. maritimus Hoover, or the seaside lupine, is a low-growing perennial plant native to western coastal regions of North America. It is known for its vibrant blue-purple flowers and ability to fix nitrogen in the soil. Here are some methods for propagating seaside lupine:
Seed Propagation
The easiest and most common way to propagate seaside lupine is through seeds. Lupine seeds have a very hard seed coat and require scarification before planting to help them germinate. To scarify lupine seeds, you can rub them with sandpaper or nick the seed coat with a sharp knife. After scarification, you can soak the seeds in water for 24 hours to help with germination.
Seaside lupine seeds should be sown in the fall when the soil is cool and moist. They can also be sown in the early spring when soil temperatures reach about 50 F°. Sow the seeds in well-draining soil about ¼ inch deep and water regularly. Germination can take anywhere from two weeks to two months.
Vegetative Propagation
Seaside lupine can also be propagated vegetatively through root cuttings or division. Root cuttings should be taken from healthy, established plants in the fall or early spring when the plant is dormant. Choose a healthy root and cut sections about 1-2 inches long. Plant the cuttings horizontally in pots or directly in the ground, making sure the top of the cutting is level with the soil surface. Keep the soil moist until roots form, which can take several weeks.
Seaside lupine can also be divided, but this method is more difficult than root cuttings. Divide established plants in the fall or early spring when the plant is dormant. Carefully dig up the plant and separate the root ball into sections, making sure each section has a healthy shoot or bud. Replant each section at the same depth as the original plant and water regularly.
Disease and Pest Management for Lupinus nanus Dougl. ex Benth. var. maritimus Hoover
Lupinus nanus Dougl. ex Benth. var. maritimus Hoover, commonly known as coastal lupine, is susceptible to a range of diseases and pests that can affect its growth and overall health. It is important to implement proper disease and pest management strategies to ensure the plant's optimal growth.
Common Diseases
Coastal lupine is vulnerable to several fungal diseases, including:
- Anthracnose: This disease is caused by the fungus Colletotrichum spp. and can lead to leaf spots, stem cankers, and even death in severe cases. To manage this disease, remove and destroy infected plant parts and apply a fungicide registered for use on lupines.
- Root Rot: This disease is caused by several soil-borne fungi and can lead to stunted growth, yellowing foliage, and wilting. To prevent root rot, plant lupines in well-draining soil and avoid overwatering. Fungicides may be used in severe cases.
- Powdery Mildew: This disease is caused by the fungus Erysiphe spp. and can result in white powdery growth on the plant's leaves. Proper spacing and pruning to increase air circulation can help prevent powdery mildew. Fungicides may be used in severe cases.
Common Pests
Coastal lupine is also prone to infestations from several pests, including:
- Aphids: These tiny insects can suck sap from the plant, causing distorted growth and yellowing foliage. Insecticidal soap can be used to manage aphids.
- Spider Mites: These pests can cause discoloration and premature leaf drop. Using a strong jet of water can help manage spider mites, as can insecticidal sprays.
In general, the best approach to managing pests is to practice good cultural care like proper watering and fertilization, as healthy plants are better equipped to resist pest infestations. Integrated pest management strategies combining different methods, including biological, cultural, and chemical control, may also be employed.
