Origin and Common Names
Calendula glabrata Thunb. belongs to the family Asteraceae (sunflower family) and is native to the southern African region. It is commonly known as the smooth calendula or horticultural marigold.
General Appearance
The plant grows up to 60 centimeters in height and has smooth, branching stems. The leaves are oval or lance-shaped, green in color, and up to 8 centimeters long. The flowerheads are 4-6 centimeters in diameter, with bright yellow or orange petals surrounding a prominent central disc.
Uses
The smooth calendula has traditionally been used for medicinal purposes in southern Africa to treat various ailments including stomach cramps and fever. Recent studies have shown that the plant contains compounds with anti-inflammatory and antioxidant properties, which may support its traditional use. Calendula glabrata Thunb. is also a popular ornamental plant, commonly used in gardens and in the horticultural industry as a cut flower.
Overall, the smooth calendula is a beautiful and versatile plant that has both decorative and medicinal uses.Growth Conditions for Calendula Glabrata Thunb.
Calendula glabrata Thunb. is a hardy annual plant characterized by its bright yellow or orange daisy-like flowers. This plant is native to southern Africa and can grow up to 15-20 inches in height. To successfully grow Calendula glabrata Thunb., the following growth conditions are necessary:
Light
Calendula glabrata Thunb. requires full sunlight to flourish. The plant should be placed in a location that receives at least six hours of direct sunlight daily. Inadequate sunlight can lead to leggy plants with fewer flowers.
Temperature
Calendula glabrata Thunb. thrives in mild temperatures. The plant prefers a temperature range of 10-27°C (50-80°F) to grow optimally. Temperatures below 0°C (32°F) can result in plant death, while high temperatures in excess of 30°C (86°F) can lead to wilted and weak plants.
Soil Requirements
The soil in which Calendula glabrata Thunb. is planted should be well-draining and fertile. The plant prefers a soil pH range of 6.0-7.5. Adding compost or aged manure to the soil can improve its fertility and texture. Avoid heavy clay soils as they can lead to poor drainage and root rot.
Overall, Calendula glabrata Thunb. is a relatively low-maintenance plant that can tolerate a range of growing conditions. With proper light, temperature, and soil requirements, this plant can produce an abundance of colorful flowers that can brighten up any garden or landscape.
Cultivation
Calendula glabrata Thunb. thrives well in well-draining soil with a pH of 6.0-7.0. It is best grown in areas with full sun exposure and a temperature between 15-25°C. The plant can be grown from seeds, and the ideal time for sowing is during the autumn season. Sow the seeds in a shallow trench about 1-2 cm deep, cover the seeds with soil, and water gently. The seedlings usually emerge within two weeks.
Watering Needs
Calendula glabrata Thunb. requires moderate watering. The soil should be kept moist but not waterlogged. Overwatering can lead to root rot and other fungal diseases. The best approach is to water the plant deeply once a week during the growing season. Reduce watering during the winter season when the plant is dormant.
Fertilization
Calendula glabrata Thunb. thrives in well-draining soil that is rich in organic matter. It is advisable to amend the soil with compost or well-rotted manure before planting. The plant does not require frequent fertilization, but it can benefit from occasional feeding during the growing season. Use a balanced fertilizer, and apply it once a month.
Pruning
Pruning is not necessary for Calendula glabrata Thunb. However, removing spent flowers can encourage the plant to produce more blooms. Use a sharp pair of scissors or pruning shears to cut off the flowers and discard them. Deadheading can help improve the plant's overall appearance and prolong its blooming period.
Propagation of Calendula glabrata Thunb.
Calendula glabrata Thunb. can be propagated through a variety of methods, including seed propagation and vegetative propagation.
Seed Propagation
Seed propagation is the most common method for propagating Calendula glabrata Thunb. This method involves collecting seeds from mature plants and planting them in soil, where they will germinate and grow into new plants. The best time to collect seeds is in the late summer or early fall, when the seed heads have dried and turned brown.
It is important to note that the seeds of Calendula glabrata Thunb. require light to germinate, so they should be planted close to the soil surface and not covered with soil. Germination typically occurs within 2-3 weeks, and seedlings can be transplanted to their permanent location once they have developed their second set of true leaves.
Vegetative Propagation
Vegetative propagation is another method for propagating Calendula glabrata Thunb. This method involves taking sections of the plant, such as stem cuttings or root cuttings, and planting them in soil to grow into new plants.
Stem cuttings should be taken from a healthy, mature plant in the spring or early summer. The cutting should be approximately 4-6 inches in length and should be taken from a non-flowering section of the plant. The lower leaves should be removed, and the cutting should be dipped in rooting hormone before being planted in soil.
Root cuttings are taken in the fall or early winter when the plant is dormant. Sections of the roots should be cut into 2-3 inch pieces and planted in soil with the top of the cutting just below the soil surface. The cuttings should be kept moist but not waterlogged, and they should develop new shoots the following spring.
Disease and Pest Management for Calendula glabrata Thunb.
Calendula glabrata Thunb., commonly known as the smooth Calendula, is a herbaceous perennial that is grown for its bright yellow and orange flowers. While this plant is generally hardy, it is susceptible to a number of pests and diseases that can affect its growth and appearance.
Common Diseases
One of the most common diseases that affect Calendula glabrata is powdery mildew, which appears as a white, powdery coating on the leaves. To manage this disease, it is important to ensure good air circulation around the plant and to water it at the base, so as not to get the foliage wet. You can also apply a fungicide if the disease has already taken hold, but prevention is key.
Another disease that can affect Calendula glabrata is leaf spot, which appears as dark spots on the leaves and can cause them to yellow and drop prematurely. Again, prevention is key, so do not water the plant from above and ensure good air circulation. If the disease has already taken hold, you can apply a fungicide.
Common Pests
One of the most common pests that affect Calendula glabrata is the aphid, which feeds on the plant's sap and can cause distortion and stunting. You can manage aphids by spraying the plant with a strong stream of water to dislodge them, or by using insecticidal soap or neem oil.
Another common pest is the spider mite, which can cause yellowing and stippling of the leaves. Spider mites are very small, so you may need to use a magnifying glass to see them. You can manage spider mites by using insecticidal soap or neem oil, or by introducing predatory mites or ladybugs.
When managing pests or diseases on Calendula glabrata, it is important to always follow the instructions on any chemical products you use, and to avoid spraying anything on the plant when it is in direct sunlight or when it is too hot. With good management practices, your Calendula glabrata should thrive and produce beautiful blooms.
