Overview
Cotula nigellifolia (DC.) K.Bremer & Humphries var. nigellifolia, commonly known as Brass buttons or Yellow buttons, is a perennial plant that belongs to the Asteraceae family. This plant is native to Australia and New Zealand, where it grows in various habitats, including sandy and rocky soils, pastures, and roadsides.
Description
Cotula nigellifolia var. nigellifolia has a small, cushion-like growth habit, with a woody base and clumps of leaves that are covered in fine hairs. The leaves are deeply divided and are usually a grayish-green color, which gives them a silvery appearance. The plant produces numerous, small, spherical, bright yellow flower heads that bloom from spring to fall and have a diameter of 1-2 cm. Each flower head contains numerous tiny florets that give the plant a cute and delicate look.
Uses
Cotula nigellifolia var. nigellifolia has various uses, both medicinal and ornamental. In traditional medicine, the plant's leaves have been used to treat wounds, skin rashes, and insect bites. The plant's flowers have also been used in teas, infusions, and tinctures to treat digestive problems, respiratory issues, and fever.
Additionally, Cotula nigellifolia var. nigellifolia is often used in landscaping as a groundcover in sunny, well-drained locations. The plant can also be grown in small pots, alpine gardens, or around rockeries. This low-maintenance plant attracts pollinators such as butterflies and bees and is a good option for gardens that support biodiversity.
General Appearance
Cotula nigellifolia var. nigellifolia is a low-growing plant that may measure up to 15cm, with a spread of about 50cm. Its small, round, and cute yellow flowers contrast nicely with its silvery gray-green foliage. The plant's seeds are tiny and develop after flowering, and can be used for propagation. Overall, this plant is easy to grow and maintain, making it a great option for gardeners looking for a versatile and attractive plant.
Light Requirements
Cotula nigellifolia (DC.) K.Bremer & Humphries var. nigellifolia is a sun-loving plant and performs best in full sun to partial shade. It requires at least 6 hours of direct sunlight per day to thrive. Plants grown in shady conditions tend to become leggy and weak, and they might not produce as many flowers as those grown in full sunlight.
Temperature Requirements
This plant is native to the southern parts of Africa and prefers warm temperatures. It can tolerate a wide range of temperatures, from lows of 20°F (-7°C) to highs of 95°F (35°C). However, it grows best in temperatures ranging from 60-80°F (15-27°C).
Soil Requirements
Cotula nigellifolia (DC.) K.Bremer & Humphries var. nigellifolia prefers well-draining, sandy or loamy soils with a neutral pH between 6.0 and 7.5. It cannot tolerate waterlogged soils and performs poorly in heavy clay soils. It grows best in soils with moderate fertility, and it is essential to avoid over-fertilizing the plant because it can cause excessive foliage growth at the expense of flowers.
Cultivation of Cotula nigellifolia
Cotula nigellifolia thrives in full sun to partial shade. It grows best in well-draining soil with a pH range of 6.5 to 7.0. The plant can tolerate light frost, but it is sensitive to harsh freezing temperatures.
Propagation can be done through seed or stem cuttings. The ideal time for propagating through stem cuttings is during spring. Ensure that you use healthy and disease-free cuttings.
Watering Needs of Cotula nigellifolia
Cotula nigellifolia requires moderate watering, and the frequency of watering will largely depend on the climatic conditions and the soil type. During the dry season, you should water the plant more often. Always make sure that the soil is moist but not waterlogged as that can lead to root rot.
Drip irrigation is an effective way of watering as it ensures that the water gets to the roots and prevents water loss through evaporation.
Fertilization of Cotula nigellifolia
Cotula nigellifolia is a light feeder, and too much fertilizer can damage the plant. The best way to fertilize is by applying compost or slow-release fertilizers once or twice a year. The application should be done during the growing season when the plant is actively growing.
Always make sure that you follow the recommended dosage to prevent fertilizer burn, which can damage the plant.
Pruning Cotula nigellifolia
Cotula nigellifolia requires minimal pruning and is generally low maintenance. However, periodic pruning can help to promote healthy growth and prevent the plant from becoming leggy.
Pruning should be done during the dormant season. You can remove any dead or diseased branches, as well as any old or woody stems. Ensure that you use sterilized pruning equipment to avoid spreading diseases from one plant to another.
Propagation of Cotula nigellifolia (DC.) K.Bremer & Humphries var. nigellifolia
Cotula nigellifolia (DC.) K.Bremer & Humphries var. nigellifolia, commonly known as yellow buttons or yellow cotula, is a low-growing perennial plant that originates from South Africa. It belongs to the Asteraceae family and is often used as a ground cover or in rock gardens. The plant is propagated by both seed and vegetative means.
Propagation by Seed
Propagation by seed is the most common method of growing Cotula nigellifolia. The plant produces small, black seeds that can be collected and sown in the spring or fall. The seeds can be sown directly into the planting site or started indoors and transplanted when they are a few inches tall.
When sowing seeds directly, it is important to prepare the planting site by removing any weeds or debris and loosening the soil. The seeds should be scattered evenly over the soil surface and lightly covered with a thin layer of soil. The seeds should be kept moist until they germinate, which typically takes 7-14 days.
If starting seeds indoors, use a well-draining seed-starting mix and place the seeds on top of the soil. Cover the seeds with a very thin layer of soil and keep them moist until they germinate. Once the seedlings have developed a few true leaves, they can be transplanted into their permanent location.
Propagation by Division
Propagation by division is another method of growing Cotula nigellifolia. This method involves dividing the plant into smaller sections and transplanting them to a new location. Division is typically done in the spring or fall when the plant is not actively flowering.
To divide Cotula nigellifolia, start by digging up the entire plant and gently shaking off any excess soil. Use a sharp knife or garden tool to cut the plant into smaller sections, making sure that each section has a healthy root system and a few stems or leaves. Replant the divided sections in their new location and water thoroughly.
Cotula nigellifolia is an easy-to-grow plant that can be propagated by seed or division. With proper care, it can quickly establish and provide an attractive ground cover in a variety of landscape settings.
Disease Management
Like most plants, Cotula nigellifolia is susceptible to various diseases. Here are some of the common diseases that might affect the plant and ways to manage them:
- Leaf Spot - Leaf spot is a fungal disease that affects the leaves of many plants, including Cotula nigellifolia. One way to manage leaf spot is to remove infected leaves and dispose of them. Fungicides may also be used to control the disease.
- Rust - Rust is another fungal disease that can affect the plant. It usually appears as yellow, orange, or brown spots on the leaves. Pruning and removing infected leaves can help manage rust. Fungicides may also be used to control the disease.
- Clubroot - Clubroot is a soil-borne disease that affects many plants, including Cotula nigellifolia. Symptoms include stunted growth, yellowing leaves, and swollen roots. To manage clubroot, avoid planting the plant in infected soil and rotate crops regularly.
Pest Management
Cotula nigellifolia is also prone to pest attacks. Here are some of the common pests that might affect the plant and ways to manage them:
- Aphids - Aphids are small insects that suck the sap out of plants. They can be managed by using insecticidal soap or horticultural oils to suffocate them. Ladybugs and lacewings can also be natural predators of aphids.
- Cutworms - Cutworms can chew through the stems of Cotula nigellifolia, causing them to wilt and die. Handpicking them in the evening or placing barriers such as cardboard collars around plants can help manage cutworms.
- Spider Mites - Spider mites are tiny pests that feed on the sap of the plant, resulting in yellow, mottled leaves. Regular washing with a strong jet of water can help control spider mites. Insecticidal soap or horticultural oils can also be used.
