Introduction
Hibiscus, belonging to the Malvaceae family, is a cosmopolitan plant with a rich history and a wide range of species. The name Hibiscus, derived from the Greek word for the Mallow plant, is a testament to its diverse lineage. The species name rosa-sinensis translates to "Rose of China", a nod to its perceived origins, although the exact birthplace of this plant remains a mystery.
The Hibiscus has been found in various parts of the world, including China, the Middle East, Southern Europe, South-East Asia, Mauritius, and the Caribbean. Its widespread presence is attributed to early explorers and traders who carried, moved, and traded these plants. As Hibiscus breeds easily, the original ancestry of the plant was lost over time.
Hibiscus Varieties
Hibiscus plants range from annuals to soft wooded shrubs and small trees. The "common garden" varieties found across the Gulf are cultivars of Hibiscus rosa-sinensis. These plants are propagated from cuttings, as seeds do not produce a plant identical to the parent plant.
In the UAE, Hibiscus is grown as a medium to large garden shrub. Small, flowering potted plants are also available and are often used for colorful table decorations. In the garden, Hibiscus plants can reach between 1.5 and 3 meters in height, making them perfect for low screening, hedges, container plants, and colorful specimen plants.
The Beauty of Hibiscus
The beauty of the Hibiscus lies in its flowers and leaves. The flowers, particularly the buds, are typically whorled or twisted in a clockwise direction, as are the leaves and branches. Each flower consists of 5 petals radiating from the base of the ovary, with the pistil, sigma, and anthers being very prominent. The flowers can measure anything from 5 cm to 20 cm in diameter, and their colors range from white to yellow, orange, pink, and red to deep maroon (including a mixture of single and double variations in between).
Healthy Hibiscus leaves are dark green, although some cultivars have bronze or variegated foliage. The leaf size varies from 5 cm to 15 cm depending on the variety and location within the garden.
Planting and Care
When planting Hibiscus, ensure the hole is at least double the diameter of the container the plant is supplied in. A mixture of 50% sweet soil and 50% compost should be used to backfill the hole. Care should be taken not to damage the root system of the plant during this process.
Hibiscus plants should be thinned out from time to time to remove old, weak growth and improve air circulation. This reduces the likelihood of insect pests and fungal infections. However, avoid pruning, cutting, or hedging during summer as this exposes the tender internal foliage to strong sunlight, which can result in the plant burning.
Pests
Insect pests that are most likely to attack Hibiscus include Aphids, Mealy Bug, Thrips, Red Spider Mite, and various beetles. Fungal pests such as Phytophthora (root rot) can also pose a threat, often caused by over-watering, poor drainage, or watering in the evening.
Treating Nutrient Deficiencies
Hibiscus plants are notorious for developing yellow leaves and showing signs of nutrient deficiencies quickly. This is often due to the high pH of the soil, which can limit the plant's ability to absorb certain nutrients. Overwatering or waterlogged soil can also result in the yellowing of the leaves. If this happens, reduce the amount of water the plant is receiving and check the drainage of the pot.
To treat nutrient deficiencies, consider the application of organic mulches. Organic mulches can help to gradually lower the pH of the soil, making it easier for the plant to absorb the nutrients it needs. Additionally, foliar applications of trace-element solutions can be beneficial. These solutions are sprayed directly onto the leaves of the plant, allowing the plant to absorb necessary nutrients directly through its foliage.
Using well-balanced fertilizers that contain a range of trace elements can also help to prevent and treat nutrient deficiencies. For established plants, consider a granular fertilizer such as 12:4:24 TE. When planting, a fertilizer like 12:24:12 TE can be beneficial. Alternate this with a foliar feed, such as a water-soluble fertilizer (like Phostrogen, Miracle Gro, BioGreen, Desert Energy General Purpose Water Soluble, etc.) that can be sprayed over the plant. This is absorbed through the pores and foliage of the plant and can be a more effective short-term measure as the fertilizer is not subject to adverse pH and saline soil conditions.
Remember, it's important not to confuse normal leaf drop with over-watering or nutrient deficiencies. Older leaves of the plant will turn bright yellow before dropping; this occurs on an ongoing basis and affects the entire plant. Yellowing of a large number of leaves or the entire plant, however, is cause for concern and may indicate a nutrient deficiency or other problem.
Hibiscus Relatives
Interestingly, the vegetable Okra, widely grown in Africa and India, is also a species of Hibiscus (H. esculentus), where the fruit (pod) is cooked. The cotton plant (Gossypium hirsutum), from which cotton fiber is derived, is also a member of the Hibiscus (Malvaceae) family. Other commonly found species of Hibiscus in the UAE include; Hibiscus syriacus (originally from Syria) and Hibiscus tiliaceus (Cotton Wood Tree), a small evergreen tree (or large shrub) with yellow flowers.
Conclusion
The Hibiscus is a versatile and beautiful plant that can add a touch of elegance to any garden. With its vibrant flowers and lush leaves, it's no wonder that it's a favorite among gardeners and plant enthusiasts.
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