Overview
Jacobaeastrum subcarnosum (DC.) Kuntze is a flowering plant that belongs to the Asteraceae family. It is also known as Senecio subcarnosus DC. and Pseudogynoxys subcarnosa (DC.) Cabrera.
Origin
The plant is native to South America, particularly Argentina, Brazil, and Uruguay.
Common Names
Jacobaeastrum subcarnosum is known by several common names, including "Rue-de-la-Sierra," "Matarofe," "Curupay," "Pitanga-de-macaco," and "Quina-roxa."
Uses
In traditional medicine, the plant has been used to treat a variety of ailments, including respiratory problems, gastric issues, wounds, and skin infections. The leaves and stems of the plant contain alkaloids and flavonoids that are said to have medicinal properties. However, there is limited scientific evidence to support its efficacy.
Additionally, the plant is grown as an ornamental for its attractive pink and yellow flowers.
Appearance
Jacobaeastrum subcarnosum is a perennial shrub that can grow up to one meter in height. It has fleshy, upright stems with gray-green leaves that are covered in fine hairs. The leaves are oval-shaped and have serrated edges. The flowers of the plant are small, tubular, and yellow in color, surrounded by pinkish-orange bracts. The plant blooms in the fall and winter.
Light Requirements
The Jacobaeastrum subcarnosum plant typically prefers bright, indirect light. It can tolerate some direct sunlight in the early morning or evening hours, but too much direct sun can lead to scorching of the leaves. Therefore, it is best to place the plant near a window, but ensure it is not in direct sunlight for extended periods.
Temperature Requirements
The Jacobaeastrum subcarnosum plant thrives in warm temperatures. It prefers a temperature range between 18-25°C (65-80°F) during the day, and a slightly lower temperature of 16-20°C (60-68°F) at night. In case of temperature fluctuations, the plant can become stressed and, on occasion, suffer from leaf drop.
Soil Requirements
This plant prefers slightly acidic soil (pH 5.1 to 6.0) with good drainage. The ideal soil mix for Jacobaeastrum subcarnosum is one that contains peat moss, perlite and/or sand and loam in a 2:1:1:1 ratio. This soil mix should be kept consistently moist, but not waterlogged. Over-watering or allowing the soil to dry out can result in damage or wilting of the leaves.
Cultivation Methods
Jacobaeastrum subcarnosum (DC.) Kuntze, commonly known as dusty miller, is a perennial plant originating from South Africa. It requires full sunlight exposure, well-draining soil, and an average temperature between 50-75°F. You can cultivate this plant either by direct sowing or transplanting. If you want to direct sow, prepare the planting site by loosening the soil and removing any weeds or debris. Sprinkle the seeds over the top of the soil and gently press them into the ground. Water the soil gently and keep it slightly moist during the germination process. If you are transplanting, prepare the soil by adding compost or well-rotted manure. Make sure the hole is deep enough to accommodate the plant's roots and has enough space for it to grow. Water the soil thoroughly and keep it moist for the first few weeks.Watering Needs
Jacobaeastrum subcarnosum requires moderate watering, and it's important not to overwater the plant, which can lead to root rot. Water the plant once a week during the growing season and reduce watering frequency during the winter. Check the moisture level of the soil before watering by sticking your finger into the soil; if the top inch of soil is dry, it's time to water.Fertilization
Jacobaeastrum subcarnosum doesn't require a lot of fertilization, but you can apply a slow-release fertilizer in the early spring. A balanced fertilizer with an NPK ratio of 10-10-10 is suitable for dusty miller. Avoid overfertilizing, which can lead to leggy growth and reduce flowering.Pruning
Pruning is an essential part of caring for Jacobaeastrum subcarnosum. The plant can grow up to 2 feet tall and can produce large, upright stems. To encourage bushiness, prune the plant by cutting back the stem tips. Also, remove the dead or damaged leaves to promote new growth. You can prune the plant in the early spring or after the flowering season.Propagation of Jacobaeastrum subcarnosum
Jacobaeastrum subcarnosum can be propagated by seeds, stem cuttings, and division.
Propagation by Seeds
Seeds of Jacobaeastrum subcarnosum can be sown directly in the ground or in containers filled with well-draining soil in the spring. The seeds are small and should be scattered on the soil and then covered lightly. Keep the soil moist and within 2-3 weeks, the seeds should germinate. Once the seedlings reach about 4-6 inches in height, they can be transplanted to their permanent location.
Propagation by Stem Cuttings
Stem cuttings from the plant can be taken during the summer from the tips of the plant's stems. Cuttings should be about 4-6 inches in length and should have at least 3-4 leaves. Remove any flowers present on the cutting and dip the cut end in rooting hormone. Plant the cuttings in well-draining soil and keep the soil moist. Within a few weeks, roots should develop, and the new plant can be transplanted to its permanent location.
Propagation by Division
Division can be done in the early spring or fall. Dig up the plant and separate the clumps into smaller ones, being careful not to damage the roots. Transplant the clumps to their permanent location. This method is effective for rejuvenating older or overgrown plants.
Disease Management
Jacobaeastrum subcarnosum is susceptible to several diseases that can lead to heavy losses. The most common diseases that affect this plant are:
- Powdery Mildew: This disease is caused by a fungus that forms a white powdery coating on the leaves, stems, and flowers. It can weaken the plant and reduce its yield. To manage powdery mildew, avoid overhead watering and provide good air circulation around the plant. Fungicidal sprays can also be used to control the disease.
- Leaf Spots: Several fungal pathogens cause leaf spots on Jacobaeastrum subcarnosum, which can lead to leaf drop and a weak plant. Avoid overhead watering, remove and destroy infected leaves, and use fungicidal sprays to control the disease.
- Root Rot: This disease is caused by a soil-borne fungus that attacks the roots and causes them to become dark, mushy, and rotten. To manage root rot, plant in well-draining soil, avoid overwatering, and remove and destroy infected plants.
Pest Management
Jacobaeastrum subcarnosum is also prone to attack by several pests. Some of the most common pests that can affect this plant are:
- Aphids: These tiny insects suck the sap from the leaves and stems, causing deformities and stunting. To manage aphids, use insecticidal soap or neem oil spray, attract natural enemies like ladybugs, or blast them off with a strong stream of water.
- Spider Mites: These pests are common in hot, dry weather and can cause a yellow or bronzing of the leaves. To manage spider mites, increase humidity around the plant, use insecticidal soap or neem oil spray, or introduce natural enemies like predatory mites.
- Caterpillars: Various types of caterpillars can feed on the leaves and flowers of Jacobaeastrum subcarnosum, causing extensive damage. To manage caterpillars, handpick them off the plants, use Bacillus thuringiensis (Bt) spray, or introduce natural enemies like parasitic wasps.
