Toona sinensis or Chinese Mahogany: Planting and Growing

Botany and description

The genus *Toona*, which includes several species, the most well-known being *Toona sinensis*, belongs to the Meliaceae family. This genus comprises five species and is distinguished by its extensive geographical distribution, ranging from Southeast Asia to Australia.

• Toona calantas or Philippine Cedar
• Toona ciliata or Australian Red Cedar (synonym: Toona australis)
• Toona febrifuga or Vietnamese Cedar
• Toona sinensis or Chinese Mahogany (or Chinese Cedar): hardy down to -15°C
• Toona sureni or Indonesian Cedar

The scientific name of the genus *Toona* derives from its indigenous Australian name. The species of the *Toona* genus are primarily distributed in Southeast Asia, India, Australia, and certain regions of the Himalayas. *Toona sinensis*, or Chinese Mahogany, the only one cultivated here due to its hardiness, originates from China and East Asia. There is some confusion regarding the naming of this tree, referred to in various sources as *Toona sinensis*, *Cedrela toona*, or *Cedrela sinensis*. However, the genus *Cedrela*, exclusively American, is now separated from the genus *Toona*, which originates from the Old World.

Toona sinensis on the left (© Forest and Kim Starr). On the right, Toona ciliata (© Dinesh Valke)

The trees of the *Toona* genus exhibit a majestic and slender silhouette, with an often upright habit and a rounded crown. The mature size can vary considerably depending on the species, but some specimens of *Toona sinensis* can reach up to 25 metres in height. *Toona sinensis* is particularly known for its relatively rapid growth, especially in its early years. By the age of ten, it can reach a height of 6 to 8 metres.

The bark of *Toona* trees is generally smooth in young specimens, becoming rougher and fissured with age. Its colour ranges from grey to brown.

The foliage is one of the most remarkable aspects of the *Toona* genus. The leaves are usually large, pinnate (composed of numerous small leaflets arranged on either side of a central axis or rachis) or bipinnate, measuring up to 60 cm in length. They consist of numerous small oval leaflets, dark green on the upper side and lighter underneath. In autumn, the leaves of *Toona sinensis* transform into a spectacle of vibrant colours. They shift from deep green in summer to a range of spectacular autumnal hues, from golden yellow to bright red, including shades of orange and copper.

The leaves display magnificent hues throughout the year

The trees of the *Toona* genus produce small white or pink flowers, clustered in racemes or panicles. The flowering of *Toona sinensis* in particular occurs between May and June. The flowers of the Chinese Mahogany are small but appear in large quantities. They are typically white, cream, or sometimes slightly pink. Each flower consists of five delicate petals and numerous prominent stamens. These flowers are grouped into long panicles or racemes that can reach several tens of centimetres in length. These pendulous clusters give the tree a highly ornamental appearance when in full bloom. One of the most remarkable aspects of the flowering of *Toona sinensis* is its fragrance. The flowers emit a sweet and pleasant aroma, often described as subtly sugary. This scent attracts various pollinators, including bees and butterflies, which are essential for the tree’s pollination. When the tree is in full bloom, it transforms into a spectacular mass of white flowers, offering a striking contrast against its dark green foliage.

On the left, flowering of a *Toona sinensis* (©Fanghong -Wikimedia Commons); on the right, *Toona ciliata* (© Dinesh Valke)

The fruits of *Toona* are woody capsules that open to release numerous small winged seeds. These seeds are dispersed by the wind, facilitating the natural propagation of the species.

The *Toona* species typically prefer well-drained and fertile soils, but some can tolerate a variety of soil types, including less fertile ones. Their root system is adapted to efficiently exploit water and nutrients. The root system of *Toona sinensis* is generally extensive and robust, suited to support its large size and height. It is a mixed root system, combining deep taproots for stability and anchoring, and widespread lateral roots for efficient absorption of water and nutrients.

The most well-known species and varieties

Toona sinensis - Chinese Mahogany

The Toona sinensis is a deciduous tree, with rapid growth, a slender habit and a light crown, bearing long, pinnate, aromatic leaves that emit an onion-like scent when crushed. The spring to summer flowering consists of long, pendulous, fragrant clusters of tiny white to pink flowers.

• Période de floraison June to August
• Hauteur à maturité 18 m

See the product sheet

Toona sinensis Flamingo - Chinese Mahogany

The 'Flamingo' cultivar stands out from the typical species with a narrower, strongly fastigiate habit, less significant development, and foliage whose colour varies with the seasons. Their colour is a shrimp pink to coppery rose highlighted with garnet veins and petioles in spring. They then take on a lighter, creamy-white tone before turning green in summer.

• Période de floraison June, July
• Hauteur à maturité 10 m

See the product sheet

Planting Toona sinensis

When to Plant?

Autumn planting is often considered ideal, especially in temperate climates. Planting during this period allows the tree to establish itself during the cool, damp months of autumn before entering winter dormancy.

Early spring, after the last frost, is also a good time to plant Toona sinensis. However, it is then important to ensure adequate watering during the summer months for young plants.

Where to Plant?

The Chinese Mahogany prefers a sunny or partially shaded location. Sufficient sunlight is important for the tree’s growth and the vibrancy of its foliage colour, especially for varieties with coloured leaves like the ‘Flamingo’ cultivar.

Well-drained soil is essential to avoid root rot problems. The Chinese Cedar adapts to a variety of soil types but thrives best in rich and fertile soil. If your soil is heavy or clayey, it may be necessary to improve drainage or add compost to enhance the soil structure. The soil pH matters little to it, as it tolerates slightly acidic, neutral, or even slightly alkaline soils.

Please note: Avoid planting Toona sinensis too close to drainage systems, septic tanks, or water lines, as its roots can spread extensively and cause problems.

The beautiful autumn colours of Toona sinensis

How to Plant?

• Dig a hole twice as wide as the root ball and as deep as the container in which the tree arrived.
• Enhance the removed soil with compost or well-rotted manure if necessary, especially if the soil is poor.
• Remove the tree from the container carefully. If the tree is delivered with a root ball wrapped in burlap, loosen the burlap at the collar and plant it all without disturbing the root ball.
• Place the tree in the hole so that the top of the root ball is level with the surrounding soil.
• Fill the hole with the amended soil, lightly firming it to eliminate air pockets.
• Water thoroughly to help establish contact between the roots and the soil.

Important! A well-established tree will tolerate short frosts of around -12 to -15°C. For the first few winters, install a thick winter fleece if very low temperatures are forecast.

Maintenance of Toona sinensis

Regular watering is essential, especially during the first few years and in periods of drought, ensuring the soil remains moist but not waterlogged. It is recommended to apply an organic mulch around the base to retain moisture and control weeds.

Pruning is generally unnecessary, except to remove dead or misplaced branches, and should be carried out in late winter or early spring.

Diseases and parasitic pests

The Toona genus cedars are relatively resistant to diseases and parasitic issues. However, the Toona sinensis can be susceptible to attacks from aphids and scale insects, which can weaken the tree and reduce its vigour. Fungal diseases, such as root rot or powdery mildew, may also develop, particularly in poorly drained soil or high humidity conditions.

Propagating a Toona

The most effective method to propagate Toona sinensis is by sowing. The seeds should be harvested at ripeness, typically in autumn, and can be sown immediately or after cold stratification if stored. To optimise germination, the seeds should be planted in a well-drained substrate and kept in moist, but not waterlogged, conditions. The ideal temperature for germination is around 20°C. The young plants require attentive care until they are robust enough to be transplanted to their final location.

Note: To faithfully propagate a variety like Toona sinensis ‘Flamingo’, it is preferable to use vegetative propagation methods such as propagation by cuttings or, even better, grafting rather than sowing.

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To enhance your Toona sinensis ‘Flamingo’, consider a setting composed of bushes and perennial ground covers that offer a harmonious contrast of textures and colours while sharing similar cultivation needs. In acidic soil, bushes such as azaleas or rhododendrons, with their vibrant flowering in shades of white, pink, or purple, will complement the pink hues of the Toona.

For ground cover, opt for perennials like hostas with their fleshy leaves, which will thrive in the partial shade of the Toona while providing a striking contrast in colour and leaf shape, particularly in the case of the Hosta ‘Halcyon’. Alternatively, a carpet of lesser periwinkle ‘Elisa’ (Vinca minor ‘Elisa’), with their delicate flowers, will create a soft harmony with the pink foliage of the Toona. Scattered here and there, heucheras with their colourful foliage—perhaps pink in the case of the ‘Wild Rose’ variety—in rounded clumps, will add interesting texture and a palette of autumnal colours throughout the year. Dwarf asters will bring a splash of vibrant colour late in the season with their generous flowering.

At the centre, Cedrela sinensis ‘Flamingo’ (© Leonora Enking), surrounded by Vinca minor ‘Elisa’, Heuchera ‘Wild Rose’, a Rhododendron ‘Roseum Elegans’, and Hosta ‘Halcyon’ (© Peganum)

Anecdotes

• The “Toona” in cuisine: The young leaves of Toona sinensis are consumed in China and known as ‘xiangchun’. They are used to flavour dishes and are particularly prized in spring, often stir-fried with garlic or incorporated into omelettes, offering a unique taste reminiscent of onion.
• A symbol of longevity: In China, Toona sinensis is considered a symbol of longevity and prosperity. This may be due to its long lifespan and imposing stature, as well as its traditional uses in medicine.
• Quality wood for instruments: The wood of Toona sinensis is highly valued for making traditional Chinese musical instruments. Its fine texture and ability to produce good sound make it a material of choice for luthiers.
• Medicinal plant: In traditional Chinese medicine, Toona sinensis is used for its medicinal properties. It is believed to have beneficial effects on the blood and the body’s internal balance.
• A tree for generations: Some Toona sinensis are planted as birth trees in China, where a tree is planted at the birth of a child and grows with them. This symbolises the child’s growth and development.

In Asia, the young shoots are used in cuisine