Origin
Justicia protracta (Nees) T.Anderson subsp. rhodesiana (S.Moore) Immelman, also called Rhodesian water willow, belongs to the Acanthaceae family and is native to southern Africa.
Common Names
Aside from Rhodesian water willow, Justicia protracta subsp. rhodesiana is also called Blue Justicia, Lengana, and Moretlwa in Botswana.
Uses
The plant is commonly used for medicinal purposes, specifically for treating coughs, colds, and respiratory infections. Its leaves are also used as a spice in traditional African cuisine. Justicia protracta subsp. rhodesiana also serves as an ornamental plant due to its beautiful purple flowers and versatility in landscaping. Its dense root system and fast growth make it a potent erosion control tool in riparian areas.
General Appearance
Justicia protracta subsp. rhodesiana is a perennial shrub that can grow up to 3 meters high. Its leaves are narrow, elliptical, and slightly curved, with a darker green color on top and a lighter shade on the underside. The plant's flowers are tubular and typically range in color from creamy white to light purple with bright yellow stamens that protrude from the petals. The plant's stems are woody, reddish-brown to grey in color, and have conspicuous lenticels.
Growth conditions for Justicia protracta subsp. rhodesiana
Light: Justicia protracta subsp. rhodesiana prefers bright, indirect light or filtered sunlight. Direct sunlight can burn the leaves and stunt the growth of the plant. Placing the plant near a south-facing window with sheer curtains is ideal.
Temperature: This plant can tolerate a range of temperatures but prefers a warm, humid environment. It is best to keep the temperature between 65°F to 85°F (18°C to 29°C). If the temperature goes below 50°F (10°C), it can damage the plant.
Humidity: Justicia protracta subsp. rhodesiana thrives in high humidity environments between 50% to 80%. In dry climates, it is recommended to use a humidifier or place a tray filled with pebbles and water under the plant to create humidity around it.
Soil: This plant grows well in well-draining, nutrient-rich soil. A mix of potting soil, peat moss, and coarse sand in equal proportions can provide good drainage. The soil pH level should be between 6.0 to 7.0.
Water: Justicia protracta subsp. rhodesiana prefers to be kept consistently moist but not overly wet. It is essential not to let the soil dry out completely. It is recommended to water the plant when the top inch of soil is dry to the touch.
Fertilizer: Justicia protracta subsp. rhodesiana benefits from regular feeding during the growing season with a balanced, water-soluble fertilizer every two weeks. Reduce the frequency of fertilizers during the dormant season.
Propagation: This plant can be propagated by taking stem cuttings in the spring or summer and rooting them in moist soil. It can also be propagated through division during a repotting period.
Cultivation Methods
Justicia protracta (Nees) T.Anderson subsp. rhodesiana (S.Moore) Immelman is a subshrub that thrives in well-drained soils. It requires a sunny location or partial shade for proper growth. Plant the subshrub in sandy loam or sandy soil, and ensure proper drainage to avoid waterlogging. Subshrub prefers a pH range of 5.5-6.5.
Watering Needs
Justicia protracta (Nees) T.Anderson subsp. rhodesiana (S.Moore) Immelman requires moderate watering. Water the subshrub when the topsoil is dry to touch. Avoid overwatering as it may lead to waterlogging, which may cause root rot. Additionally, water the subshrubs near the base of the plant and avoid wetting the foliage.
Fertilization
Justicia protracta (Nees) T.Anderson subsp. rhodesiana (S.Moore) Immelman requires minimal fertilization, mainly if planted in fertile soil. Apply a slow-release fertilizer with a ratio of 5:10:5 N:P:K every three months, starting at the onset of the growing season. Moreover, the use of organically sourced compost manure is an excellent alternative.
Pruning
Justicia protracta (Nees) T.Anderson subsp. rhodesiana (S.Moore) Immelman requires minimal pruning. Remove dead, damaged, or diseased foliage regularly to avoid pest infestations. Additionally, remove old or woody growth periodically to encourage the growth of new and vigorous shoots. You can prune the subshrub in late winter to promote new growth and ensure the plant maintains its shape.
Propagation of Justicia protracta (Nees) T.Anderson subsp. rhodesiana (S.Moore) Immelman
Justicia protracta (Nees) T.Anderson subsp. rhodesiana (S.Moore) Immelman is a semi-succulent shrub that belongs to the family Acanthaceae. It is native to Southern Africa and is commonly known as Rhodesian justicia. Propagation of this plant can be achieved through various methods, including the following:
Seed Propagation
Seeds of Justicia protracta subsp. rhodesiana are readily available, and propagation by seeds is a viable option. Freshly harvested seeds should be sown in well-draining soil that is kept moist until germination, which occurs after approximately three weeks. Seedlings should be pricked out and transferred into appropriately sized pots once they are large enough to handle. It is important to note that the plant's growth rate is slow, and it may take up to three years for the plant to reach maturity.
Cuttings Propagation
Propagation through cuttings can be done using both softwood and hardwood cuttings. Softwood cuttings should be taken in spring or the early summer when the plant is actively growing. Hardwood cuttings, on the other hand, should be taken in autumn or winter when the plant is dormant. The cuttings should be dipped into rooting hormone powder and inserted into sandy soil or vermiculite to promote rooting. The cuttings should be kept moist until they have developed enough roots to be transplanted into appropriately sized pots or directly into the ground.
Division
Justicia protracta subsp. rhodesiana can also be propagated through division. This method entails separating the plant's root system into two or more sections using a sharp knife or spade. Each section should have some roots and several stems, and the soil should be kept moist until new growth appears.
Overall, Justicia protracta subsp. rhodesiana is a unique plant that can be propagated through various methods. Plant enthusiasts and horticulturists can explore these methods to increase their collection of this plant or use it for landscaping purposes.
Disease and Pest Management for Justicia protracta subsp. rhodesiana
Justicia protracta subsp. rhodesiana is generally a hardy plant that is not prone to many fungal diseases or pest infestations. However, it is not completely immune, and being aware of the potential diseases and pests that can affect the plant is important in ensuring its sustained health.
Common Diseases and their Management
One of the most common diseases that can affect Justicia protracta subsp. rhodesiana is powdery mildew. This fungal disease appears as a white, powdery coating on the leaves, and can lead to stunted growth and reduced flowering.
To manage powdery mildew, it is important to improve air circulation around the plant by spacing it out from other plants and removing any nearby weeds. Fungicidal sprays can also be used, but it is important to use them as directed and not exceed recommended dosages to avoid damaging the plant and the environment.
Another disease that can affect the plant is root rot, which is caused by a fungal infection in the soil. Symptoms of root rot include yellowing leaves and wilting, and in severe cases, the plant may die.
To prevent and manage root rot, it is important to ensure that the plant is not overwatered and that it is growing in well-draining soil. Fungicidal treatments can also be used, but again, it is important to avoid overuse and follow instructions carefully.
Common Pests and their Management
One of the most common pests that can affect Justicia protracta subsp. rhodesiana is spider mites. These tiny insects suck the sap out of the leaves, causing them to turn yellow and eventually die off.
To manage spider mites, it is important to regularly inspect the plant for signs of infestation, and to spray it with a miticide if necessary. Additionally, keeping the plant well-watered and misting the leaves can help deter spider mites.
Another pest that can affect the plant is mealybugs. Mealybugs are small, white insects that form cottony masses on the leaves and stems. They also suck sap from the plant, causing stunted growth and yellowing leaves.
To manage mealybugs, it is important to manually remove them by wiping them off with a cloth dipped in alcohol. Alternatively, insecticidal sprays can be used, but again, it is important to follow instructions carefully to avoid damaging the plant.
Overall, regular inspection and maintenance of Justicia protracta subsp. rhodesiana can help prevent and manage potential diseases and pests, ensuring the plant remains healthy and vibrant.
