Origin and Common Names
Erysimum capitatum (Dougl. ex Hook.) Greene var. capitatum, commonly known as sanddune wallflower or western wallflower, is a member of the mustard family Brassicaceae. The plant is native to western North America, from Alaska to California, and can thrive in sandy or rocky soils at elevations from sea level to 11,500 feet.
Uses
The sanddune wallflower is used as an ornamental plant due to the striking beauty of its flowers. It blooms in spring and early summer with clusters of fragrant and colorful flowers, typically yellow, orange, or a combination of the two, and occasionally pink or red. The plant is also valued for its medicinal properties, as it contains compounds that have anti-inflammatory and pain-relieving effects. Additionally, the leaves and roots of the plant are used to make a tea that is believed to be helpful in treating respiratory and digestive problems.
General Appearance
The sanddune wallflower is a perennial plant that can grow up to two feet tall and two feet wide. It has narrow, lance-shaped leaves that can be up to six inches long and are either blue-green or gray-green. The plant's stem is sturdy and unbranched, and it terminates in a cluster of flowers. The flowers are four-petaled and grow up to one inch in diameter. The plant's fruit is a long, narrow pod that contains many small seeds. Overall, the sanddune wallflower is a hardy and attractive plant that can bring color and fragrance to a variety of settings, from sandy coastal dunes to rocky mountain slopes.
Light
Erysimum capitatum var. capitatum prefers full sun to partial shade for optimal growth conditions. In areas with hotter climates, it can benefit from some afternoon shade to prevent leaf scorching.
Temperature
This plant species is well-suited to grow in a wide temperature range, from hot, arid regions to cool, mountainous areas. In general, it can tolerate temperatures as low as -20°F (-29°C) and as high as 104°F (40°C). However, it experiences optimal growth when temperatures range from 50°F (10°C) to 80°F (27°C).
Soil
Erysimum capitatum var. capitatum prefers well-draining soils that are slightly acidic to neutral with a pH range of 6 to 7.5. It can also handle clay soils as long as they are adequately drained. This plant species does not tolerate waterlogged soils and can suffer from root rot if the soil is consistently wet. Additionally, it can grow in nutrient-poor soils, such as rocky or sandy soils, but it benefits from occasional fertilization with a balanced fertilizer.
Cultivation Methods
Erysimum capitatum is a hardy plant that can thrive even in poor soil conditions. However, it prefers well-draining soils that are rich in nutrients. The best time to plant Erysimum capitatum is in the spring, after the last frost has passed. It is best to plant it in full sun, but it can also tolerate some shade.
It is advisable to space the plants about 12 inches apart to allow for proper growth and development. It is essential to keep the soil consistently moist for the first few weeks until the plant establishes itself. Afterward, it requires minimal care and watering.
Watering Needs
Although Erysimum capitatum is relatively drought-resistant, it is essential to keep the soil moist during its early growth stage. Water your plant whenever the top inch of soil feels dry to the touch. Avoid overwatering as it can cause root rot and other fungal diseases. Once the plant is established, it can tolerate dry soil conditions for extended periods.
Fertilization
It is advisable to fertilize Erysimum capitatum once a month during the growing season (spring and summer). Use a balanced fertilizer, such as a 10-10-10 or 20-20-20 NPK formula. Follow the instructions on the label for application rates and frequency. Do not fertilize during the dormant season (winter) as it may cause new growth that can be damaged by frost.
Pruning
Erysimum capitatum requires minimal pruning, but it can benefit from deadheading to encourage new growth and blooms. Deadheading involves cutting back spent flowers and stems to the nearest leaf node. It helps to prevent seed formation and redirects the plant's energy into producing better growth and flowers. You can also prune the plant in early spring before the growing season to remove any dead or damaged wood and improve its overall appearance.
Propagation of Erysimum capitatum (Dougl. ex Hook.) Greene var. capitatum
Erysimum capitatum (Dougl. ex Hook.) Greene var. capitatum, commonly known as western wallflower, is a beautiful plant that can be found in western North America. The plant has yellow or orange flowers and is popular among gardeners. The plant is typically propagated through seeds and cuttings.
Propagation by seeds
The seeds of western wallflower are small and can be easily propagated. The plant produces seeds in the summer months, which can be collected and sown in the fall. The seeds should be sown in well-drained soil and watered regularly. The seeds will germinate in two to four weeks and will grow into mature plants in one to two years.
Propagation by cuttings
Erysimum capitatum (Dougl. ex Hook.) Greene var. capitatum can also be propagated by cuttings. Cuttings are typically taken in the spring or summer months, when the plant is actively growing. The cuttings should be taken from the new growth and should be four to six inches long. The cuttings should be dipped in rooting hormone and planted in well-drained soil. The cuttings should be watered regularly and will develop roots in two to four weeks.
Propagation of Erysimum capitatum (Dougl. ex Hook.) Greene var. capitatum can be a rewarding experience for gardeners. Whether through seeds or cuttings, this plant is easy to propagate and can add beauty to any garden.
Disease Management
Erysimum capitatum is prone to a few fungal diseases, such as powdery mildew, rust, and black spot. To manage these diseases, it is important to maintain good plant hygiene practices. This includes getting rid of all fallen leaves and debris, watering the plants at the base and not overhead, and providing good air circulation around the plants. Additionally, you can use fungicides to control or prevent the spread of these fungal diseases, following the manufacturer's instructions carefully.
Gray mold or Botrytis Blight is another common disease of Erysimum capitatum, which is caused by the fungus Botrytis cinerea. The disease causes grey-brown lesions on leaves and stem rot, which eventually kill the plant. To manage this disease, it's recommended to promote good air circulation and avoid overwatering the plant. Removing infected plant parts and applying fungicides can also help control this disease.
Pest Management
Several pests can attack Erysimum capitatum, including aphids, spider mites, and flea beetles. These pests can cause significant damage to the plant, including leaf curling, yellowing, stunting, and sometimes death of the plant. To manage these pests, it's important to monitor the plants regularly and take preventive measures. Use insecticidal soaps or botanical insecticides to control small infestations, making sure only to spray in the early morning or late afternoon to conserve pollinators and beneficial insects. For larger infestations, use insecticides recommended for the specific pest.
Snails, slugs, and caterpillars can also damage Erysimum capitatum, leading to irregular holes in the leaves or complete defoliation. To manage these pests, you can handpick them from the plant and place a copper strip or mesh around the base of the plant to prevent their movement. You can also use bait spraying with iron phosphate or metaldehyde, which is toxic to snails and slugs.
It's essential to regularly monitor your Erysimum capitatum for pests and diseases, identifying and treating them early on to prevent major infestations and spread. By implementing these pest and disease management practices, you can keep your Erysimum capitatum healthy, beautiful, and thriving.
