Overview
Psydrax subcordata (DC.) Bridson var. subcordata is a small tree species belonging to the Rubiaceae family. It is native to several Pacific islands, including New Caledonia, Fiji, Samoa, Tonga, and Vanuatu.
Common Names
The plant goes by different common names depending on the region, including 'Kadavu Wattle', 'Kadau', 'Mauve', 'Nairobi Berry', and 'Sepetang'.
Uses
The tree has several traditional and medicinal uses. In Samoa, the leaves are used to make a decoction for treating coughs, while in Fiji, the leaves and bark are used to treat fevers and headaches. The leaves, bark, and roots of the plant are also used by locals in Vanuatu to treat diarrhea, dysentery, and malaria.
Aside from its medicinal and traditional uses, the tree's wood is also used for making small items such as bowls and spoons. The bark is used to make string for weaving in some cultures, while the leaves are used as a natural dye source.
General Appearance
The tree grows up to 10 meters high, with a compact, rounded crown. The leaves are elliptic, 7-20 cm long and 3-5 cm wide. They are dark green, glossy, and have prominent veins on the underside. The flowers are small, white, and clustered in terminal panicles that are up to 8 cm long. The fruit is a green, fleshy drupe that turns purple-black when ripe and contains one seed.
Light Requirements
Psydrax subcordata var. subcordata grows best in full sun to partial shade. It can tolerate a few hours of direct sunlight, but too much sun exposure can lead to leaf scorching. On the other hand, inadequate light can lead to leggy growth and poor flowering.
Temperature Requirements
The plant prefers warm temperatures and cannot withstand frost. It thrives in tropical and subtropical regions with average daytime temperatures between 20°C and 35°C. At night, the temperature should not drop below 10°C. Therefore, it is not suitable for areas with long cold winters.
Soil Requirements
Psydrax subcordata var. subcordata prefers well-drained soils with a pH range of 5.5 to 7.5. It can grow in various soil types, such as loamy, sandy, or clay soils. However, the soil must be rich in organic matter and should not be compacted. The plant may suffer if planted in heavy clay soils with poor drainage.
Cultivation Methods
Psydrax subcordata (DC.) Bridson var. subcordata, commonly known as the heavywood, is a hardy and adaptable plant that can thrive in a range of conditions. It prefers well-draining soils but can tolerate a variety of soils, including sandy, loamy, and clay soils.
It grows best in bright, indirect light or partial shade. Direct sunlight can be too intense and may scorch the leaves of the plant. Heavywood can be grown outdoors in USDA Hardiness Zones 9 to 11, but it is sensitive to frost and prefers temperatures above 60°F. If grown in colder climates, it must be protected from the winter cold.
Watering Needs
Psydrax subcordata (DC.) Bridson var. subcordata prefers moist, but not water-logged soil. It is important to let the soil dry out between waterings, as overwatering can lead to root rot. In the summer months, the plant requires more frequent watering, while in the winter months, it can be watered less often.
The amount of water required will depend on the size of the plant and the environment it is growing in. It is recommended to water the plant deeply once a week and to increase the frequency during hot, dry weather.
Fertilization
Psydrax subcordata (DC.) Bridson var. subcordata can benefit from regular fertilization to promote healthy growth. It is best to use a slow-release fertilizer or to fertilize the plant every two to three months during the growing season, from spring to fall.
When planting the heavywood, it is a good idea to mix a slow-release fertilizer into the soil. This will provide the plant with the necessary nutrients as it establishes its roots. In addition, regular applications of compost or other organic matter can help improve soil fertility.
Pruning
Pruning Psydrax subcordata (DC.) Bridson var. subcordata can help promote a bushier, more compact growth habit. It can be pruned during the growing season to control the height and shape of the plant, though heavy pruning should be avoided as it can cause stress to the plant.
Dead or damaged branches should be pruned as soon as they are noticed to prevent the spread of disease. Pruning during the winter months should be minimized, as the plant is less actively growing and may have a harder time recovering from the stress of pruning.
Propagation of Psydrax Subcordata (DC.) Bridson var. subcordata
There are several methods by which Psydrax subcordata (DC.) Bridson var. subcordata can be propagated.
Seed Propagation
Psydrax Subcordata can be propagated through seeds. The seeds should be collected when mature, and sown immediately to enhance their germination rate. It is important to use fresh seed as the viability of the seed may decline with time. The seeds can be sown directly into the soil or in containers. When sown, they should be covered lightly with soil and watered regularly to keep the soil moist.
Cuttings Propagation
Cuttings of Psydrax Subcordata can also be taken for propagation. The cuttings should be taken from mature, healthy plants at the beginning of the growing season. The cutting should be approximately 10-15 cm in length, and the lower leaves should be removed. The cutting should be dipped in rooting hormone to increase its chances of rooting. After that, the cutting should be planted in a pot filled with soil and kept in a warm, humid area for the initial few days. In a few weeks, the cuttings should start rooting and can be transplanted to permanent positions.
Air Layering Propagation
Air Layering is another method of propagating Psydrax Subcordata. In this method, a branch of the plant is selected, and bark is removed slightly in a small area. The wound is then covered with a layer of soil wrapped in a plastic sheet. After about 6-8 weeks, roots should develop in the buried area. Once the roots are established, the new plant can be separated and repotted in a new location.
Division Propagation
Psydrax subcordata can also be propagated through division. This method involves separating the plant into two or more sections and planting each division separately. This method is usually done when the plant is mature and starts becoming too large for its current position. The plant is dug up, and the rootball is carefully divided, with each division having some roots and a proportionate amount of leaves. Each new section is then planted in a new location.
Disease and Pest Management for Psydrax subcordata (DC.) Bridson var. subcordata
Psydrax subcordata (DC.) Bridson var. subcordata, also known as ironwood or mabea, is a small to medium-sized tree that is vulnerable to a number of pests and diseases. Here are some common problems and management strategies:
Diseases
Leaf Spot and Blight: These two diseases are caused by the fungi Cercospora and Alternaria, respectively. Symptoms include yellowing and browning of leaves, often starting at the tips and margins, and progressing inward. To manage these diseases, remove infected leaves and spray a fungicide containing copper or chlorothalonil.
Root Rot: This disease is caused by the fungus Phytophthora and is most likely to occur in areas with poor drainage or where plants have been overwatered. Symptoms include wilting, yellowing or browning of leaves, and stunted growth. The best way to manage root rot is to improve soil drainage and avoid overwatering. Fungicides containing mefenoxam or metalaxyl can be used in severe cases.
Pests
Scale Insects: These pests suck the sap from leaves and stems, causing yellowing and wilting. They produce a sticky substance called honeydew, which can attract ants and other insects. To manage scale insects, remove them by hand or wash the tree with a soap solution. In severe cases, insecticides containing imidacloprid or acetamiprid can be used.
Aphids: These pests also suck sap from leaves and stems, causing yellowing and curling. They also produce honeydew, which can attract ants and sooty mold. To manage aphids, wash the tree with a strong stream of water or spray with insecticidal soap. Insecticides containing neem oil or pyrethrin can also be used.
Whiteflies: These pests are small, winged insects that feed on the underside of leaves and suck sap from the tree. They also produce honeydew, which can attract ants and sooty mold. To manage whiteflies, use sticky traps or vacuum them up with a handheld vacuum. Insecticidal soap or oil sprays can also be effective.
By implementing these disease and pest management strategies, you can help prevent and control common problems that may afflict your Psydrax subcordata (DC.) Bridson var. subcordata plant, and keep it healthy and thriving.
