Overview
Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. is a plant species endemic to Africa. It is a shrub or small tree that usually grows in woodland areas, forests, and scrublands. This plant belongs to the Lamiaceae family, which also includes other well-known species like mint, rosemary, and thyme.
Common Names
The plant is known by different common names depending on the region. In Swahili, it is called "Mweri" or "Umweri," while in Kikuyu language, it is known as "M?tangatanga." In Tanzania, it is called "Mkindu," "Mvule," "Mpomodoro," or "Mvunja mwitu."
Appearance
Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. is a small tree or shrub that can grow up to 8 meters tall. The plant has a rounded crown and a single stem. The bark is grey-brown and rough, while the leaves are simple, opposite, and usually 7-15 cm long. The leaves are dark green, glossy, and elliptic in shape, with finely serrated margins.
The inflorescences of this plant are formed by spikes that emerge from the axils of the leaves. The flowers are small and tubular, with a pinkish-white color, and they usually bloom from June to September (in East Africa). The fruit is a round, greenish-brown drupe that contains a single seed.
Uses
In East Africa, Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. has many medicinal uses. The bark, leaves, and roots are commonly used for treating various ailments, including malaria, diarrhea, fever, and stomachache. Some cultures believe that the plant has supernatural powers, and they use it to ward off evil spirits or bad luck.
In addition to its medicinal uses, the wood of Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. is hard and durable, making it ideal for making furniture, tool handles, and other household items. The leaves and twigs can also be used as fodder for livestock.
Light Requirements
Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. thrives in bright to moderately shaded environments. In its natural habitat, this plant can be found growing under the canopy of trees, where filtered sunlight is available. Exposure to direct sunlight for extended periods may cause leaf scorching and reduced growth rate.
Temperature Requirements
Preferred growth temperature for Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. is between 20°C to 30°C (68°F to 86°F). This plant can tolerate cold temperatures but is not frost hardy. In colder regions, it is best grown as an indoor plant where it can be protected from extreme cold and frost.
Soil Requirements
Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. thrives well in well-draining soils with a pH of 6.0 to 7.5. The soil should be rich in nutrients and organic matter. A soil mix that combines a significant percentage of perlite, vermiculite, and peat moss is ideal for this plant’s growth.
Cultivation
Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. is a small to medium-sized tropical plant that can grow indoors or outdoors. It is best grown in full sun or partial shade and requires well-draining soil that is enriched with organic matter. This plant can grow up to 6 feet in height if allowed.
Propagation of the plant can be done by stem cuttings or by seed. Stem cuttings should be taken from healthy plants and rooted in a well-draining soil mix. The plant can also be grown from seed, which should be sown in a prepared seedbed or in a well-draining potting mix.
Watering Needs
Watering of the plant should be done regularly, especially when the plant is grown in well-draining soil. The plant prefers moist but not soggy soil. Overwatering can lead to root rot and other fungal diseases. Watering should be reduced during the winter months to prevent waterlogging of the soil.
Fertilization
The plant should be fertilized regularly during the growing season to encourage healthy growth. A water-soluble fertilizer with a balanced N-P-K ratio (10-10-10 or 15-15-15) can be used for this purpose. Organic fertilizers like compost and manure can also be used to enrich the soil.
Pruning
Premna resinosa (Hochst.) Schauer subsp. holstii (Gürke) Verdc. requires regular pruning to maintain its shape and size. Pruning should be done in early spring when the plant starts to show new growth. Dead, diseased, or damaged branches should be removed to improve the plant's overall health. The plant can also be pruned to promote branching and encourage the growth of new shoots.
Propagation of Premna Resinosa subsp. Holstii
Premna Resinosa subsp. Holstii can be propagated through various methods that can be summarized as follows:
Seeds
The easiest way to propagate this subspecies is through seeds. The seeds are collected from ripe fruits and sown in a nursery. Germination usually starts within 10-15 days after sowing.
Cuttings
Propagation through cuttings is also possible. Semi-hardwood cuttings should be taken during the rainy season and rooted in a mixture of sand and peat moss. Rooting hormones can be applied to speed up the process.
Air Layering
Air Layering is another method through which Premna Resinosa subsp. Holstii can be propagated. This method involves cutting a ring of bark around a branch and covering it with soil or moss. Roots will develop at the cut area, and the new plant can be separated from the parent after rooting.
Division
Division is a propagation method that involves dividing the root ball of an established plant into two or more parts and transplanting them. This method can be used for mature, multi-stemmed plants. It is important to ensure that each division has sufficient roots and foliage to support its growth.
Disease Management:
Premna resinosa subsp. holstii is generally considered a hardy plant with limited susceptibility to diseases. However, it is prone to fungal infections which can cause leaf spot disease. Fabric conditioners such as amphotericin B, and Daconil are effective against these fungal infections.
The symptoms of fungal infections in Premna resinosa subsp. holstii include yellowing and drooping leaves, stunted growth, and the development of dark spots on the leaves. These symptoms can also be controlled by removing and destroying the affected plant parts. Regular application of fungicides prevents the occurrence and spread of fungal infections.
Pest Management:
Several insect pests can affect the growth and development of Premna resinosa subsp. holstii. One of the most common insect pests is the aphid, which can cause stunted growth, yellowing of leaves, and curling leaves. Application of neem oil or insecticidal soap is effective against aphids.
Another insect pest that can affect this plant is the spider mites which cause significant damage to the leaves of the plant. These can be managed by spraying water on leaves or using insecticidal soap.
Mealybugs are also a common pest that can infest Premna resinosa subsp. holstii. These bugs can be controlled by the application of insecticidal soap and carefully wiping them away from the plant with a cotton swab.
Prevention is always better than cure, so regular monitoring of the plant and early detection of pests is essential. Isolating infected plants from healthy ones can also prevent pest infestations. Keeping the plant healthy with good air circulation and the right amount of moisture and light, ensures the plant's resilience to pests and diseases.
