Origin
The plant Berkheya onopordifolia (DC.) O.Hoffm. ex Burtt Davy var. glabra Bohnen ex Roessler is native to South Africa. It is commonly found in the Western and Eastern Cape provinces.
Common Names
The plant has several common names such as "silver berkheya" and "cypress-leaved berkheya".
Uses
Berkheya onopordifolia is prized for its ornamental value and is often used in gardens and landscapes. It is also used in traditional medicine to treat a variety of ailments such as arthritis and fever. In addition, it has medicinal properties and is used to treat wounds and bruises.
General Appearance
The Berkheya onopordifolia plant is a perennial shrub that can grow up to 1.5 meters tall. The silver-grey leaves are thin and spiky, and have a cypress-like appearance. The flowers are a bright blue-purple color and bloom in clusters at the end of a long stem. The plant prefers well-drained soil and full sun exposure.
Growth Conditions of Berkheya onopordifolia var. glabra
Light Requirements: Berkheya onopordifolia var. glabra prefers full sun to partial shade. In its natural habitat, it grows on rocky slopes and in open areas, sometimes under the shade of larger plants.
Temperature Requirements: This plant is adapted to dry and warm conditions. It can tolerate a wide range of temperatures, from 10-35°C (50-95°F), but it prefers temperatures between 20-30°C (68-86°F). It will not tolerate frost or freezing temperatures.
Soil Requirements: Berkheya onopordifolia var. glabra grows best in well-draining soils and can tolerate a wide range of soil types, from sandy to loamy to rocky. It can grow in poor soils, but fertilization will improve the growth rate and flower production.
Watering Requirements: This plant is drought-tolerant and can survive long periods without water. However, for optimal growth and flower production, it is recommended to water regularly during the active growing season and reduce watering during the dormant season.
Fertilization: If the soil is poor or lacking nutrients, fertilization with a balanced fertilizer can be beneficial for growth and flowering. Fertilizer can be applied in the spring and only once or twice a year.
Propagation: Berkheya onopordifolia var. glabra can be propagated by seeds or cuttings. Seeds should be sown in the spring, while cuttings can be taken in the early summer. It is essential to keep the soil moist during the propagation process, and a rooting hormone can be applied to cuttings to improve success rates.
Cultivation Methods
Berkheya onopordifolia (DC.) O.Hoffm. ex Burtt Davy var. glabra Bohnen ex Roessler is a hardy perennial plant that can grow well in a diversity of growing conditions. It thrives well in well-drained soil with a pH range of 6.0 - 7.5, in areas with plenty of sunlight. The plant is tolerant of drought and can survive in hot, dry environments. However, it does not grow well in wet soils, and efforts should be made to ensure that the soil is adequately drained.
The plant can be propagated through the division of rootstock or by sowing seeds. Seeds should be sown in the spring in a seedbed and then transplanted to their permanent position when they are big enough. The optimal distance between plants is about 40 - 50cm. This is because the plant tends to spread out and can take up quite a bit of space.
Watering Needs
Berkheya onopordifolia (DC.) O.Hoffm. ex Burtt Davy var. glabra Bohnen ex Roessler does not require excessive watering. In fact, it is a drought-tolerant plant and can thrive well in dry soils. However, during extended periods of drought, it is essential to water the plant to ensure that it does not become too dry.
The plant is susceptible to root rot if the soil is waterlogged for long periods. Therefore, it's essential to ensure that the plant is not overwatered.
Fertilization
To keep the Berkheya onopordifolia (DC.) O.Hoffm. ex Burtt Davy var. glabra Bohnen ex Roessler plant healthy, you can add compost or dried manure to the soil during planting. This will provide a slow-release source of nutrients to the plant.
If the plant begins to show signs of nutrient deficiency such as yellowing leaves, you can add a balanced fertilizer every four to six weeks from early spring to late summer. Make sure to use a fertilizer that is high in potassium and low in nitrogen.
Pruning
The Berkheya onopordifolia (DC.) O.Hoffm. ex Burtt Davy var. glabra Bohnen ex Roessler plant does not require much pruning. However, deadheading spent flowers can encourage further blooming, extend the flowering period, and encourage lush growth.
Pruning can also be done for aesthetic reasons to improve the shape of the plant or reduce its size. It's important to sterilize pruning tools before use to prevent the spread of diseases between plants. You can do this by wiping the blades with rubbing alcohol or dipping them in disinfectant.
Propagation of Berkheya onopordifolia var. glabra
Berkheya onopordifolia var. glabra can be propagated by seeds, division, cuttings, and layering.
Propagation by seeds
The seeds of Berkheya onopordifolia var. glabra can be sown directly outdoors in the fall or after the last frost of spring. The seedlings take about 2-3 years to mature and bloom. The seeds should be sown in well-draining soil, kept moist, and placed in a sunny location.
Propagation by division
Division is a quick and easy way to propagate Berkheya onopordifolia var. glabra. The plant should be dug out from the ground and shaken off any soil. Then, divide the plant into smaller sections, making sure each section has its roots. The divided plant should be replanted in well-draining soil, kept moist, and placed in a sunny location.
Propagation by cuttings
Berkheya onopordifolia var. glabra can also be propagated by cuttings. Take cuttings of about 3-4 inches in length from the plant's new stem growth in the spring or summer. Remove the leaves from the bottom half of the cutting and dip the cutting in rooting hormone. Then, plant the cutting in well-draining soil, place it in a humid location, and water regularly.
Propagation by layering
Propagation by layering involves burying a portion of the plant stem while it is still attached to the mature plant. Bend the stem to the ground, making sure the section to be buried is in contact with the soil. Use a small stone or wire to hold down the section to be buried. After a few weeks, roots should develop from the buried section. Cut the new plant apart from the parent plant and replant in well-draining soil in a sunny location.
Disease and Pest Management for Berkheya Onopordifolia
Berkheya onopordifolia is a hardy perennial plant that is resistant to many pests and diseases. However, some diseases and pests can affect the plant if not managed properly. Here are some common diseases and pests that might affect the plant and ways to manage them.
Common Diseases
1. Powdery Mildew – This disease is caused by a fungus that appears as a white powdery substance on the leaves and stems of the plant. To manage this, remove the affected leaves and make sure the plant is provided with adequate air circulation to prevent the disease from spreading.
2. Leaf Spot – This disease is caused by a fungus that creates brownish spots on the leaves of the plant. To manage this disease, remove the affected leaves and avoid overwatering the plant to prevent the fungus from spreading.
Common Pests
1. Aphids – These small insects feed on the sap of the plant and can cause deformities in the growth of the plant. To manage them, use insecticidal soap or neem oil to prevent them from infesting the plant. Regular spraying of water to its leaves may help reduce aphids.
2. Spider Mites – These pests are not insects but are a kind of arachnid. They create webbing on the plant and suck the sap. To manage spider mites, apply insecticidal soap or neem oil to the plant, and keep it well-hydrated to prevent them from infesting the plant.
3. Slugs – These pests feed on the foliage of the plant and can cause significant damage. To manage slugs, use slug bait or physically remove them from the plant with your hands regularly. Eliminating any standing water anywhere around the plant can also help reduce the population of slugs.
By managing the plant’s disease and pest issues, it is possible to keep the Berkheya onopordifolia plant healthy and thriving for many years.
