Overview:
Corethrogyne filaginifolia var. viscidula, also known as sticky-leaved sand aster, is a perennial herbaceous plant that belongs to the Asteraceae family. It is native to California and Baja California, Mexico.
Appearance:
The plant grows up to 1 meter tall and 1 meter wide. Its foliage consists of long and narrow leaves that are slightly curled under, making them appear tubular. The leaves are dark green and sticky, hence the common name. The flowers of sticky-leaved sand aster are purple or lavender and bloom from July to October.
Uses:
Sticky-leaved sand aster is used in habitat restoration projects and as an ornamental plant in gardens and landscapes. It can be planted in coastal areas, meadows, and desert regions where it can serve as a food source for bees, butterflies, and other pollinators. The plant is also used in traditional medicine for the treatment of coughs, colds, and respiratory ailments.
Cultivation:
Sticky-leaved sand aster can grow in a variety of soils, including sandy, loamy, and clay soils, as long as they are well-drained. The plant prefers full sun to partial shade and is drought-tolerant once established. It can be propagated through seeds or cuttings and requires minimal maintenance.
Light Requirements
Corethrogyne filaginifolia var. viscidula prefers full sun to partial shade and requires a minimum of six hours of direct sunlight each day. Shaded environments can cause the plant to grow spindly and produce fewer flowers.
Temperature Requirements
The plant thrives in a mild Mediterranean climate and prefers temperatures between 60-80°F (16-27°C) with moderate humidity. During winter, the temperature should not dip below 40°F (4°C) as it can cause leaf damage and overall poor plant growth.
Soil Requirements
The plant prefers well-draining soils that are enriched with organic matter. It can grow in sandy, rocky soil types, making it adaptable to different conditions. The pH range for optimal growth is between 6.0-7.5. A soil test can help identify any deficiencies in the soil, and amendments can be added accordingly.
Cultivation Methods
Corethrogyne filaginifolia (Hook. & Arn.) Nutt. var. viscidula (Greene) Keck, commonly known as yellow sand aster, is a native California plant that grows well in full sun to partial shade. It can tolerate a wide range of soil types and is drought-tolerant once established. It is best to sow the seeds directly in the ground in the fall as they require a period of stratification before they can germinate.
Watering Needs
Yellow sand aster requires infrequent deep watering during the hot summer months if there is not enough rainfall. Overwatering can lead to root rot and fungal diseases. Allow the plant to dry slightly between watering, and avoid getting water on the foliage to prevent the spread of diseases.
Fertilization
Yellow sand aster is a low-maintenance plant and does not require much fertilization. However, applying a light amount of a balanced fertilizer in the spring can encourage healthy growth. Avoid fertilizing the plant in late summer as this can promote late-season growth that is susceptible to frost damage.
Pruning
Yellow sand aster requires very little pruning, but it can be beneficial to deadhead the spent flowers to promote continued blooming and prevent self-seeding. If the plant becomes too large or unruly, it can be pruned back to maintain its shape in the winter or early spring.
Propagation of Corethrogyne filaginifolia var. viscidula
Corethrogyne filaginifolia var. viscidula can be propagated using both sexual and asexual propagation methods. The plant can be grown from seeds or through vegetative propagation.
Seed Propagation
The seeds of Corethrogyne filaginifolia var. viscidula can be collected from the matured flowers of the plant. The seeds can be sowed in the early spring or late fall season. The seeds should be sowed at a depth of around 1/8 inches in the soil with good drainage. The seedlings of the plant will emerge within 2-4 weeks of sowing. The seedlings should be watered regularly and fertilized with a balanced fertilizer to promote growth.
Vegetative Propagation
Corethrogyne filaginifolia var. viscidula can be propagated through stem cuttings or division. Stem cuttings should be taken during the late spring or early summer season. The cuttings should be taken from matured stems of the plant and should have 2-3 nodes. The cuttings should be treated with a rooting hormone and planted in a pot with well-draining soil. The pot should be placed in a warm and humid place with indirect sunlight. The cuttings will develop roots in 3-4 weeks and can then be transplanted into the garden. Division can be done during the spring season when the plant is actively growing.
Disease Management
Corethrogyne filaginifolia var. viscidula is prone to fungal infections such as rust, powdery mildew, and root rot. To manage these diseases, it is important to maintain good cultural practices such as planting in well-draining soil, providing adequate air circulation, and avoiding over-crowding of plants. If the disease is already present, apply appropriate fungicides such as copper-based fungicides or sulfur-based fungicides.
Pest Management
Aphids, spider mites, and whiteflies are common pests that can infest Corethrogyne filaginifolia var. viscidula. To manage these pests, start by inspecting plants regularly and removing any infested plant parts. Introducing natural predators such as ladybugs and lacewings can also help control pest populations. If the infestation is severe, use insecticidal soap or horticultural oils as an alternative to chemical pesticides.
