Radermachera sinica (Bignoniaceae) Care Guide: Growing Methods, Precautions, Watering, and How to Save a Leaf-Dropping Plant

“Radermachera sinica” has the scientific name Radermachera sinica. It is a common landscaping plant that purifies the air and lifts the mood, and families and offices alike love to grow it. So what are the growing methods and precautions for Radermachera sinica? How often should it be watered? How do you save a plant that is dropping leaves?

Indoors, Radermachera sinica is usually grown in a pot and placed in the living room or study. A study is an elegant, quiet and orderly place, and its plants should be calming and soothing, which is exactly what Radermachera sinica does; palm plants or foliage plants are also suitable for a study.

Growing Methods

Soil

Radermachera sinica likes loose, fertile soil that drains well and is rich in humus. The soil mix for Radermachera sinica bought directly from outside is generally garden soil + leaf mold + decomposed organic fertilizer + river sand, mixed in a 5:3:1:1 ratio. These days, though, perlite or vermiculite is mostly added to the soil to prevent it from compacting.

Water

Radermachera sinica likes a humid environment. During the growing period it needs not only fairly high ambient humidity but also a certain level of soil moisture; in spring, however, while the buds are sprouting and new shoots are growing, water should be controlled appropriately to keep the branches from growing leggy.

In spring, water once every 2 to 3 days; in summer and autumn, when temperatures are higher, water once every 1 to 2 days; in winter, control water appropriately and water once every 7 days. When watering, pay attention to the weather: choose a sunny day to water, and do not water on cloudy days. In addition, during hot, dry seasons, spray the plant every day to maintain a certain humidity, so that the leaves do not lose water, turn yellow and drop.

Temperature

Radermachera sinica likes a warm, hot and humid environment, and its optimum growing temperature is between 20 and 30 degrees. When the environment exceeds 30 degrees, shade it appropriately, increase humidity and spray the leaves, or move it to a cool, ventilated place. When the temperature drops below 10 degrees, move Radermachera sinica into a shed. During the winter, the indoor temperature should not be lower than 8 degrees, and at minimum not below 5 degrees, to avoid cold damage or leaf drop.

Humidity

Radermachera sinica likes a humid environment, and air humidity is generally kept at 70 to 80 percent. A well-ventilated bathroom has excellent humidity! When placed indoors at home, the plant can often be sprayed with slightly warm clean water to keep the leaves fresh and also raise the air humidity.

Light

Radermachera sinica likes light and tolerates a little shade; it can grow in full sun or in a semi-shaded environment. It behaves differently at different growth stages: seedlings are fairly shade-tolerant and only grow well with shading; mature plants are best placed at an indoor window with plenty of light, sometimes in full light and sometimes in indirect light. If Radermachera sinica grows in a dark environment for a long time, it easily drops its leaves.

Fertilizing

Every year in April, as the temperature rises, move Radermachera sinica outdoors to grow, and while repotting, add a certain amount of compound fertilizer to the soil; once it enters the peak growing season, apply decomposed liquid fertilizer once a month, and after the Mid-Autumn Festival apply a phosphorus and potassium fertilizer once to strengthen the plant's cold resistance and ensure it overwinters safely.

Note that when the summer temperature is above 32 degrees C, or the winter temperature is below 12 degrees C, fertilizing should stop. At these temperatures Radermachera sinica grows slowly and absorbs fertilizer poorly, so fertilizer sitting in the potting soil for a long time easily causes fertilizer burn.

Small Radermachera sinica

The small Radermachera sinica is the same plant as Radermachera sinica, but people seem to prefer the mini version. The small Radermachera sinica is special because its leaves are so glossy they look almost fake, and it is very beautiful. There is no difference in how the small and large Radermachera sinica are grown; the environment is the same, and only the amount of watering and fertilizing needs to be adjusted according to the size of the pot. Generally speaking, a smaller pot means water evaporates faster, so according to how wet or dry the potting soil is, shorten the watering interval appropriately.

Growing Precautions

Avoid Cold Damage

Summer and winter are the hardest times for Radermachera sinica: it is either too hot or too cold. Heat is manageable, but cold easily damages the plant. So after winter begins, promptly move Radermachera sinica indoors and keep the temperature above 10 degrees C. If insulated improperly and the temperature stays below 5 degrees C for a long time, cold damage and leaf drop are very likely.

Pests and Diseases

Radermachera sinica fears cold in winter and stuffiness in summer, and a hot, stuffy environment easily leads to all kinds of pests and diseases. Prevention should be done in good time. Once small insects appear on the leaves, spray pesticide immediately and improve ventilation. If leaves turn yellow and drop, promptly clean away the yellowed leaves and spray a fungicide.

What to do if Radermachera sinica drops its leaves?

There may be 3 reasons:

1. It may be caused by too much watering together with poor ventilation, with the leaf tips turning dry and yellow

2. The main cause is dry indoor air; spraying the leaves with clean water 2 to 3 times a day can effectively prevent the tips of newly emerging leaves from turning dry and yellow.

3. If growth is normal there is no problem; sometimes a change of environment causes some old leaves to drop.

It may also be caused by the plant being in too dark an environment with insufficient light. You can place it in a brighter spot, and when the temperature is below 20 degrees C it also needs a full-sun environment. In addition, consider whether too much fertilizer was applied, and whether the organic fertilizer used was fully decomposed.

What to Consider When Placing Radermachera sinica in Different Spots

Placing Radermachera sinica in the Study

A study is an elegant, quiet and orderly place, and the plants there should be calming and soothing; Radermachera sinica serves this purpose, and palm plants or foliage plants are also suitable for a study. Because the wealth position in a study is best filled with large-leaved plants to gather wealth, a Radermachera sinica with very lush, well-grown leaves is a good choice to place there. Working there is also more beneficial. There are many other considerations for a study; as long as you pay attention, you can enhance Wenchang, and with the power of Wenchang, achieve better results than others in study and exams; otherwise it is hard to concentrate, efficiency drops and mistakes come easily. So Radermachera sinica is very suitable for placing in a study.

Placing Radermachera sinica on the Balcony

The balcony is the most open place in the home; it can take in outside sunlight, air, wind and rain, and is where the home draws in energy. Placing plants on the balcony has two functions: dissolving bad energy and generating prosperity. If, looking out from the balcony, the nearby environment is beautiful scenery with no ill-shaped features in sight, then prosperity-generating plants can be placed there. A large Radermachera sinica, with dense, verdant leaves full of vitality, can serve as a prosperity-generating plant, and it also carries the meaning of bringing happiness to people, so it is even more beneficial to our home. Generally speaking, balcony plants that generate prosperity in feng shui are tall and sturdy, and the thicker, larger and greener they are, the better, so everyone can choose a large, sturdy Radermachera sinica.

About the Benefits of Radermachera sinica

The Benefits of Radermachera sinica

1. It is a tropical plant. Radermachera sinica is also known as Radermachera sinica, chili tree and mountain Radermachera sinica. It has a graceful form and swaying shadows, and its leaves are small and emerald green, making it a very precious indoor ornamental plant. Radermachera sinica belongs to the genus Radermachera in the family Bignoniaceae and is a tropical tree. It is also the representative tree of Hawaii, and because people believe it can bring happiness, many choose to grow it.

2. It is a medium-sized deciduous tree. The bark of Radermachera sinica appears light gray with deep vertical fissures. Its opposite middle leaves are ovate-lanceolate with tailed tips. The leaf rachis is about 30 cm long, with 2 to 3 times pinnately compound leaves. The flowers of Radermachera sinica are borne in upright, terminal inflorescences and are night-blooming, with ovate-lanceolate calyx teeth and linear-lanceolate bracts. The corolla is bell-shaped and funnel-form, white or pale yellow, 6 cm to 8 cm long, with round, wrinkled lobes; the capsule is leathery, cylindrical and elongated like a bean, slightly curved and with many grooves.

3. Its living environment. Radermachera sinica is native to the tropical and subtropical regions of southern China, and by nature likes high temperatures, high humidity and a sunny environment. It tolerates high temperatures, prefers moisture, fears cold and dislikes dryness; for cultivation, use loose, fertile loam and sandy loam that drains well and is rich in organic matter. It can be propagated by cuttings, sowing, layering and other methods. For cultivation, sandy loam is best, with full sun or partial shade; the optimum growing temperature is 28 degrees C to 28 degrees C, and a pruning and shaping should be done before spring growth begins. During indoor display, besides keeping the potting soil moist, the leaves should also be sprayed frequently, and the plant should be placed in a spot with plenty of light. This plant, which symbolizes happiness and peace, does not demand much from its growing conditions and is especially suitable for lazy gardeners.

4. Radermachera sinica has good medicinal value. First, its roots, its leaves and its fruit can all be used medicinally. If there are symptoms such as internal heat or fever, the roots, leaves and fruit of Radermachera sinica can be used to cool the blood, reduce swelling and bring down fever. And in cases of bruises and injuries or bites by venomous snakes, Radermachera sinica can likewise be used for treatment, with very obvious effects.

5. Radermachera sinica contains anti-cancer elements. As early as 40 years ago, scientists were already able to extract camptothecin, used to treat cancer, from Radermachera sinica. Researchers at the BC Cancer Research Centre in Canada used nanotechnology to extract an anti-cancer drug from the bark of Radermachera sinica and named it Irinoph or eC. At present at least one company is studying this drug.