Albizia lenkoranica

Albizia lenkoranica, also known as the lankaran albizia, is a striking deciduous tree or large shrub from the legume family, distinguished by its airy, lace-like foliage and delicate, fluffy flower clusters. It is also referred to as lankaran acacia in cultivation, although biologically it is not related to true acacias. This plant is widely used in ornamental gardening due to its elegant appearance and ability to tolerate a relatively wide range of climatic conditions.

Etymology of the name

The genus name albizia was given in honor of filippo del albizzi, an 18th-century italian naturalist who introduced some members of the genus to europe. The species epithet lenkoranica is associated with the history of its discovery and growth in the lankaran region (southern azerbaijan), from where it was introduced into botanical collections. The plant became further known as "lankaran acacia" due to its visual similarity to acacia and the name of the region of origin.

Life form

In the wild, lankaran albizia often takes the form of a small tree reaching 6–10 meters in height. The tree typically has a single main trunk, although specimens with multiple trunks splitting near the ground are occasionally found. The crown is usually umbrella-shaped or spreading, creating a visual effect of a lacy, "umbrella-like" cover.

In cultivation, the height and shape largely depend on pruning methods and climatic conditions. If needed, lankaran albizia can be shaped into a shrub, especially if the top is regularly pinched. This flexibility, combined with its attractive flower clusters, makes the plant popular in landscape design.

Family

Lankaran albizia belongs to the legume family (fabaceae), which includes both herbaceous and woody forms characterized by pod fruits and a distinctive flower structure (butterfly-type in the subfamily mimosoideae, to which albizia belongs). This family includes important agricultural and ornamental species (peas, beans, acacia, robinia).

Members of the legume family often have the ability to fix nitrogen through symbiotic bacteria in root nodules. This property is not as pronounced in albizia lenkoranica, but the general characteristics — compound (feather-like) leaves typical of mimosa plants and the flower cluster form — indicate its relatedness to other legume species.

Botanical characteristics

The leaves of lankaran albizia are compound, often up to 20 cm long, divided into many small leaflets that fold at night or under stress. The flowers are gathered into fluffy racemose clusters (sometimes spherical), made up of long, threadlike stamens in shades of pink, white, or pink-white. These "silk-like" stamens give the plant its common name, "silk tree."

After flowering, flat pods measuring 10–15 cm in length form, containing several seeds. The pods typically mature in late summer to early autumn, turning brown and eventually splitting open to release the seeds. The trunk and branches of young plants are smooth, but with age, the bark may become rougher.

Chemical composition

The fruit and leaves of lankaran albizia contain various phenolic compounds, flavonoids, and tannins. Proteins and carbohydrates typical of legumes are also present. The seeds are rich in stored nutrients necessary for germination. Some studies indicate the presence of compounds with antioxidant and potentially anti-inflammatory properties, although the plant's official medicinal use is not confirmed.

Origin

The genus albizia is naturally distributed in tropical and subtropical regions of the old world — africa, asia, including the mediterranean basin and the caucasus. Albizia lenkoranica, as the name suggests, was initially discovered and described in the lankaran region (southern azerbaijan), but it is also found in iran and other regions with suitable climates.

As an ornamental plant, lankaran albizia was introduced to various countries where the climate allows the tree to winter without severe frosts. It has become established along the black sea coast of the caucasus, in crimea, and in some mediterranean areas, where it has become a popular element in park and garden landscaping.

Ease of cultivation

For gardeners in moderately warm regions, lankaran albizia is considered relatively easy to grow if provided with plenty of sunlight, well-drained soil, and moderate moisture. However, young seedlings may be sensitive to severe freezing temperatures, so in colder regions, the tree is grown only in protected greenhouses or similar structures.

When planting, it is important to consider the potential size of the tree and provide adequate space for the root system and crown. Watering is more frequent in the early years to help the plant establish, after which it demonstrates good drought resistance. Regular fertilization promotes rapid shoot growth.

Species and varieties

The genus albizia includes several dozen species, among which lankaran albizia (albizia lenkoranica) is considered one of the most commonly cultivated, along with the closely related albizia julibrissin, which some authors consider a synonym. Various forms and hybrids with varying stamen colors are found in ornamental horticulture, though there are not many specific commercial varieties.

Albizia lenkoranica

Albizia julibrissin

Size

In favorable climates, lankaran albizia can reach heights of 6–10 meters, and sometimes more, with a broad, flat, umbrella-shaped crown. This creates the effect of a delicate top that provides pleasant partial shade on the site. In limited space or in colder climates, the height is typically smaller (2–4 meters).

The crown is often formed in a fairly spreading shape, with a diameter of 3–5 meters or more in mature specimens. With pruning and shaping, the size of the tree can be adjusted in both width and height to meet landscape needs.

Growth rate

Young seedlings, under optimal conditions (warmth, sunlight, regular watering), can show moderate growth (about 30–50 cm per season). In older trees, the growth rate slows down, and the tree adds about 15–25 cm annually.

Growth is influenced by soil quality, light and water availability, and nutrients. Under poor conditions (poor drainage, lack of trace elements, excessive shading), annual growth may be minimal, often resulting in irregular flowering and weakened ornamental value.

Lifespan

In the wild, lankaran albizia can live for 50 years or more, with abundant flowering in mature age (around 3–5 years). In cultivation, many specimens retain their vitality and ornamental value for 20–30 years, especially if rejuvenating pruning is done and the tree is kept in good phytosanitary condition.

Over time, older trees may experience trunk damage, rot, and reduced flowering intensity. However, proper care — including moisture control, fertilization, and timely sanitation pruning — helps maintain albizia in satisfactory condition for as long as possible.

Temperature

Lankaran albizia prefers a warm subtropical climate and easily withstands summer heat (around 30°c and higher) as long as sufficient watering is provided. The optimal temperature for vigorous growth is 20–25°c.

In winter, cold tolerance is limited: frosts below -15°c can be fatal to young seedlings. Mature trees, with thick trunks and a developed root system, can withstand brief temperatures as low as -18°c, but the risk of branch damage and reduced future flowering is high. In colder regions, growth is hindered, and the plant requires special protection.

Humidity

Moderate humidity (40–60%) is sufficient for the normal growth of lankaran albizia in outdoor conditions. A humid coastal climate promotes faster growth and abundant flowering. In a dry continental climate, frequent misting (in a greenhouse) or more frequent watering may be necessary.

The plant does not have high humidity requirements, but in extremely dry air, leaf tips may dry out, and buds may fall off. If grown indoors, regular misting or using humidifiers will help maintain the necessary micro-humidity.

Lighting and placement in a room

Bright sunlight or light partial shade is optimal. For outdoor cultivation, open sunny areas with light shading in the midday hours are recommended to avoid stress from extremely high temperatures. For indoor cultivation (which is quite rare for this species), choose a south or southwest-facing windowsill, adjusting shading as needed.

Lack of light leads to elongated shoots, weak flower bud formation, and reduced leaf decorativeness. To compensate, grow lights can be used, especially in northern latitudes during winter. Moving the plant outdoors (balcony, terrace) during the warm months is a good way to provide it with the necessary dose of direct sunlight.

Soil and substrate

Lankaran albizia requires light, air- and water-permeable soil with a slightly acidic reaction (ph 5.5–6.5). In open ground, this may be fertile loam with good drainage or a sandy-loamy substrate enriched with organic matter (manure, compost).

When growing in a container, the substrate is made from:

• Soddy soil (2 parts)
• Leaf soil (1 part)
• Peat (1 part)
• Sand or perlite (1 part)

A drainage layer (expanded clay, gravel) 2–3 cm thick should be placed at the bottom of the pot to prevent root rot from excessive watering.

Watering

During active growth (spring and summer), water lankaran albizia regularly, keeping the soil moderately moist. It is not recommended to let the soil dry deeper than 2–3 cm, as young roots may suffer from lack of moisture. However, waterlogging, especially in cool weather, is very dangerous as it leads to root rot.

In winter, if the plant sheds some leaves or enters dormancy, watering is reduced. In indoor cultivation at temperatures of 15–18°c, water the soil every 7–10 days, carefully ensuring the substrate does not become waterlogged.

Fertilization and feeding

To support abundant growth and flowering, fertilize albizia from spring to summer (every 2–3 weeks) with complex mineral fertilizers or organic infusions (manure, humus). Fertilizers rich in phosphorus and potassium can be used, as they stimulate flowering and strengthen shoots.

The application method may be root watering with a fertilizer solution or surface scattering of granules, which are then worked into the top layer of soil. In autumn and winter, fertilization is minimized or completely stopped to give the plant a chance to rest before the new growth cycle.

Flowering

Lankaran albizia produces striking fluffy flower clusters shaped like "balls" or racemes, where the numerous thread-like stamens play the main role, in shades of pink, white, or pink-white. The flowering period typically occurs in mid-summer or early autumn, depending on the climate zone.

In warmer regions, flowering can last for several weeks, filling the air with a light fragrance. With proper lighting and care, albizia can bloom profusely, decorating the garden or greenhouse.

Propagation

Lankaran albizia is propagated by seeds and cuttings. Seeds (from the pods) are sown in spring in a loose substrate (a mix of sand and peat) at a temperature of 20–25°c. Germination occurs within 2–3 weeks, requiring sufficient light and watering. However, flowering may take several years to begin.

The vegetative method of propagation involves using semi-woody cuttings 10–15 cm long in the first half of summer. They are planted in a moist mix of peat and sand, kept at 22–

24°c with regular misting. Root formation takes 3–4 weeks, after which rooted cuttings can be transplanted into pots.

Seasonal features

In spring, active growth begins, with leafing and, under favorable conditions, bud formation. During this period, it is important to increase watering and start fertilizing. In summer, the plant reaches its peak of growth and flowering, requiring regular watering, especially during dry periods. Weeds are removed, and sanitary pruning is done if necessary.

In autumn, after flowering, the albizia may shed some leaves (depending on the climate and variety). Reducing watering and stopping fertilization helps the plant prepare for winter. In colder climates, the plant is either protected with covering in open ground or moved to a cool, non-freezing space.

Care features

The main points of care for lankaran albizia include ensuring light, moderate watering, and protection from cold. It is important to control moisture levels: overwatering is unacceptable, but drying out should also be avoided, especially during active growth and flowering.

Regular pruning or pinching of shoots in spring helps shape a beautiful crown and stimulate more abundant flowering. In conditions of high humidity and poor ventilation, fungal diseases may occur, so it is important to periodically ventilate the room (if kept indoors) and monitor leaf condition.

Care in indoor conditions

When grown indoors, lankaran albizia is typically placed in spacious greenhouses, winter gardens, or glassed-in balconies where there is sufficient light and space. It is important to use well-drained pots with light substrate. Watering should be done with warm, settled water, allowing the top layer to dry by 1–2 cm.

Fertilization with mineral fertilizers is done every 3–4 weeks during the spring-summer period, while in winter, it is stopped or significantly reduced if the plant's activity decreases. The temperature should be kept no lower than 12–15°c. Proper crown support is important if the tree has tall shoots.

If space is limited, lankaran albizia can be shaped into a small shrub by periodically shortening the stems. Regular misting of leaves may be beneficial but should be done with proper ventilation and sufficient warmth.

However, it should be noted that for full flowering and development, the tree may require more light and space than a standard apartment can provide. It thrives best in enclosed winter gardens or large, spacious rooms with large windows.

Repotting

In container culture, young plants can be repotted annually in spring, increasing the pot size by 2–3 cm in diameter. Adult plants should be repotted every 2–3 years or as needed, when the roots have completely filled the root ball.

Before removal, the substrate should be moistened, the plant gently removed with its roots, and transferred to a new container with fresh drainage. The mix is made of leaf (or soddy) soil, peat, and sand. After repotting, watering should be moderate, and the plant should be allowed to acclimate, avoiding direct midday sun for the first 1–2 weeks.

Pruning and shaping the crown

Pruning is recommended in late winter or early spring, before active growth begins. Sanitary pruning removes damaged, dry, and diseased branches, improving airflow and allowing more light to reach the central part of the crown.

Shaping pruning can be used to regulate the height and width of the crown. If a bushy form is needed, the central stem is shortened and lateral branching is encouraged. For a tree-like shape, the main leader is left, removing excessive side shoots.

Possible problems and solutions

Overwatering or water stagnation in cool weather can lead to root rot. The plant wilts, and the leaves turn yellow. Immediately reduce watering, and if necessary, repot, removing rotting roots.

Lack of light leads to elongated shoots, weak or absent flowering. Move the pot to a sunnier window or use grow lights. Inadequate nutrients result in chlorosis of the leaves and slow growth, which can be addressed with regular balanced fertilization.

Pests

Among pests, lankaran albizia can be attacked by spider mites, aphids, whiteflies, and scale insects. Preventative measures include leaf and stem inspections, maintaining moderate humidity, and avoiding excessive moisture.

If insects appear, use insecticides and acaricides according to the instructions. For mild infestations, use folk methods (soap solution, washing leaves), and in severe cases, use chemical treatments with reapplication after 7–10 days.

Air purification

Lankaran albizia, due to its foliage, can absorb small amounts of co₂ and release oxygen, improving the indoor microclimate. However, the effect is not very large considering the tree's size. Nonetheless, any live greenery positively affects overall comfort, reducing stress levels in people.

Additionally, the presence of leaves and branches can trap small amounts of dust, slightly raising humidity through evaporation from leaf surfaces. No significant impact on filtering harmful chemical compounds has been noted, but general greening has a positive effect on the environment.

Safety

Lankaran albizia is not considered dangerously toxic, but it is advised to avoid consuming seeds or any other parts of the plant. Allergic reactions to pollen are rare but possible for people sensitive to flowering plants.

If there are small children or pets in the house, care should be taken to prevent them from chewing the leaves or breaking branches. In general, albizia does not contain strong toxic alkaloids like some members of the legume family, and the danger to humans is minimal with normal contact.

Wintering

In regions with moderately mild winters (for example, the black sea coast, some areas with winters no colder than -10°c), lankaran albizia can overwinter in the open ground. Young plants (up to 3–5 years) should be protected with nonwoven material and the root zone mulched to protect against frost.

In harsher climates, the plant is dug up and moved to a container, stored in a cool, but not freezing, space (5–10°c). Watering is reduced, and no fertilization is carried out. In spring, as temperatures warm, the tree is replanted in the open ground or returned to its permanent location.

Beneficial properties

In addition to its high ornamental value, albizia can somewhat improve soil composition, like many legumes, due to its symbiotic relationships with nitrogen-fixing bacteria. This can help enrich the substrate with nitrogen and promote healthier soil microflora.

Moreover, it attracts pollinators (bees, butterflies) during its flowering period, which enhances biodiversity in the garden. In some cultures, the flowers and leaves have been used as natural dyes, though this is not of significant economic importance.

Use in traditional medicine or folk remedies

Reliable information on the official medicinal use of albizia lenkoranica is scarce. However, folklore sources mention the possible use of bark or leaves for minor inflammations or wound treatments. There is no scientific confirmation of the effectiveness and safety of these methods, and the internal consumption of plant derivatives is not recommended.

Preliminary experimental data indicate the presence of antioxidant compounds in some parts of the plant, but clinical studies have not been conducted. Therefore, the use in folk medicine lacks reliable confirmation, and any attempts should be made with great caution.

Use in landscape design

Lankaran albizia is highly valued for its lace-like, umbrella-shaped crown and fluffy flowers. In regions with mild winters, it is often used as a solitaire on lawns, giving the area an exotic look. Unlike traditional coniferous or deciduous plants, albizia adds a vibrant palette of blooming racemes.

Vertical gardens or hanging compositions for the tree are not relevant, as it forms as a large specimen. However, in spacious gardens, near gazebos, or along alleys, albizia creates picturesque avenues. Its impressive foliage and delicate flower fragrance, combined with other tropical and subtropical species, create the atmosphere of a southern garden.

Compatibility with other plants

Lankaran albizia pairs well with flowering shrubs (hibiscus, bougainvillea, jasmine), giving the area a vibrant tropical feel. It can also be combined with small conifers (thuja, juniper), especially if contrast in form and color is desired.

It is not recommended to plant the tree near plants that require abundant watering and may shade the root zone or compete for water. Balanced fertilization and the knowledge that albizia's root system can enrich the soil with nitrogen are positive factors for companion plantings.

Conclusion

Albizia lenkoranica (lankaran albizia) is an attractive tree with a lacy crown and impressive pink-white flower clusters, capable of decorating gardens in areas with mild climates and becoming a valuable exhibit in greenhouses and winter gardens. Its soft, compound leaves and fluffy flowers give the plant unique appeal, creating a light southern atmosphere.

When selecting this species for your garden or collection, keep in mind the need for ample sunlight, moderate watering with good drainage, and protection for young seedlings from cold. Under favorable conditions, lankaran albizia delights for many years, forming a captivating focal point and adding a light tropical touch to the landscape.