Propagation Techniques and Cultivation Methods for the Flamboyant Tree (Delonix regia)

Because of its bright red or orange flowers combined with bright green bipinnate leaves, Delonix regia is known as one of the most brilliantly coloured trees in the world. It is widely planted in botanical gardens and parks in the cities of southern China as an ornamental tree or street tree. Below is an introduction to the propagation techniques and cultivation techniques of the “flamboyant tree” Delonix regia!

I. Growth Habits of Delonix regia

Delonix regia is a tropical tree species. It begins to flower after 6 to 8 years of planting. It prefers a high-temperature, humid environment with plenty of sunlight. Its optimum growing temperature is 20 to 30°C, and it is not cold-tolerant; the winter temperature should not fall below 10°C. Deep, fertile, sandy loam rich in organic matter is ideal. It is afraid of waterlogging, so drainage must be good. It is relatively drought-tolerant and tolerant of poor, thin soil. Generally, a one-year-old plant can reach a height of 1.5 to 2 m, and a two-year-old plant can reach 3 to 4 m. It begins to flower after 6 to 8 years of planting. In South China, winter buds sprout in early February each year, and the growth peak is from April to July. In late July, because the temperature is too high, growth decreases. After mid-to-late August, as the temperature drops, growth speeds up again. After October, growth slows down, and leaves fall from December to January of the following year.

II. Propagation Techniques for Delonix regia

Delonix regia is mainly propagated by sowing. The seeds mature in December. Collect the pods and take out the seeds for dry storage, then sow in the following spring. Before sowing, soak the seeds in boiling water, and after it cools, continue soaking for 1 to 2 days, changing to clean water 1 to 2 times in between. After sowing, germination begins in 6 to 7 days, and all seedlings can emerge in more than 20 days. One-year-old seedlings can reach about 1.5 m. Young seedlings are relatively sensitive to frost. In the early stage, a balanced fertilizer may be applied, with less nitrogen fertilizer. After autumn begins, fertilization should be stopped to encourage early lignification. In winter, if the leaves have not yet fallen, they can be removed manually, and plastic film covering or individual wrapping can be used to prevent frost. One-year-old seedlings can be lifted from the nursery and planted out.

III. Cultivation Techniques for Delonix regia

1. Site selection

Delonix regia does not have high soil requirements, and it can also grow well on relatively poor, thin soil because its roots have rhizobia, which can fix nitrogen and increase soil fertility. However, waterlogging will kill the rhizobia and affect plant growth. Therefore, a fertile, deep, well-drained, sunny location should be chosen for planting.

2. Timely transplanting

Delonix regia seedlings need to be transplanted once after 1 to 2 years of growth. Transplanting is best done in early spring, with a plant-to-row spacing of about 60 cm. Three-year-old seedlings can be used for planting out. The planting site should be open and sunny. In dry weather, water thoroughly. Transplanting before bud break in spring gives a high survival rate. Planting can also be done in the rainy season, but part of the branches and leaves should be pruned to ensure survival.

3. Timely pruning

Delonix regia has strong sprouting ability and can be trained into large seedlings by the trunk-cutting method. After planting out, loosen the soil and weed 2 to 3 times each year, water in a timely manner, apply a topdressing once each in spring and autumn, and promptly remove root suckers to ensure good tree growth. The trunk will grow branches and leaves at any time, and if allowed to grow naturally, the plant shape will vary greatly, so frequent pruning is required.

4. Pest and disease control

The main pests of Delonix regia are noctuid moths, whose larvae feed on the leaves of the plant and cause damage, often eating all the leaves of the host plant and seriously affecting tree growth and ornamental value. The damage is most severe in July, August and September. Control should seize the period when the larvae gather in groups to cause damage, and dust powder in the early morning before the dew has dried. You can dust with 2.5% trichlorfon powder, 1.5% parathion (1605) powder, or 1.5% dimethoate powder, at 1.5 to 2 kg per mu.

The above is Tuliu.com's introduction to the propagation techniques and cultivation techniques of Delonix regia. Delonix regia is the national tree of the Republic of Madagascar in Africa, the city flower of Shantou City, Guangdong, China, and the city tree of Xiamen City, Fujian, Tainan City, Taiwan, China, and Panzhihua City, Sichuan.