The Tamarind Bonsai: The Exotic that Sleeps at Night

The Tamarind(Tamarindus indica) is a bonsai tree that immediately takes the imagination to distant, warm lands. It is a tropical evergreen tree (in our climates often semi-deciduous) prized for its elegant feathery foliage composed of small, light-green leaves and dark, wrinkled bark that gives it a vine-like appearance even at a young age. One of its magical features is its noctynasty: at dusk, its leaves fold and close in on themselves, as if the tree is going to sleep, only to open again at dawn.

Origin & species

Native to tropical Africa (but widespread for millennia in India and Asia), it is the only species in the genus Tamarindus. It belongs to the Fabaceae (Leguminosae) family. In the wild, it is an imposing tree that produces the famous bittersweet brown pods used in cooking. As a bonsai, it is loved for its hardiness and ease of cultivation, as long as its thermal requirements are met.

Exposure and Microclimate

Tamarind loves warmth and light.
Summer: Place it outside in full sun. Direct light is essential to maintain small leaves and short internodes. It is not afraid of scorching heat; in fact, it likes it.
Winter: It is a tropical plant. If you live in northern or central Italy, you should bring it indoors or into a heated greenhouse as soon as temperatures drop below 10-12°C. Choose a very bright location, away from cold drafts.

Watering

Like many tropical plants, it wants fresh but not soggy soil.
Water generously when the surface of the substrate begins to dry. It drinks a lot in summer.
Beware of dry air: If kept indoors in winter, air from radiators is its enemy. Mist the foliage often with demineralized water or use a saucer with moist expanded clay to create a favorable microclimate.

Water quality

It tolerates tap water, but prefers water that is not overly calcareous. If you notice white deposits on the leaves or soil, alternate with rainwater or distilled water to wash away excess salts.

Substrate

Requires a draining soil that avoids stagnation (lethal to roots) but retains necessary moisture.

• Recommended mix: 50% Akadama, 30% Pumice and 20% Universal Potting Soil or Humus.
• The organic component is important to nourish this vigorous plant and not let the root ball dry out too much.

Repotting

It is done in late spring (May-June), when night temperatures are stably above 15-18°C.
Tamarind has vigorous tap roots. Repot young ones every 2 years. When repotting you can shorten the central taproot to encourage fine lateral roots, but do not be too drastic if the plant is not in perfect health.

Fertilization

This is a year-round growing plant if kept warm.
Fertilize from spring to fall with solid organic fertilizer.
If you keep it indoors in the warmth in winter and it continues to vegetate (put on new leaves), you can continue to lightly fertilize with a liquid product once a month. On the other hand, if it goes dormant (loses leaves or stops), discontinue.

Flowering and fruiting

In nature it produces yellow flowers streaked with red and then edible pods.
In bonsai it is very rare to see it flower, unless it is an old specimen grown under ideal conditions (tropical greenhouse). Enjoy the beauty of the foliage and bark.

Structure pruning

Major cuts are made in late spring, when the plant is in full thrust.
The wood is hard but brittle at the same time. Remove branches that grow vertically or cross the trunk. Always protect cuts with mastic; Tamarind tends to withdraw sap if the wound dries out too much.

Maintenance pruning

Regularly prune off new shoots that become too elongated during the growing season.
This stimulates internal branching and keeps the foliage compact. If a branch becomes too long, the leaves at the base will tend to fall off, leaving it bare: prune it short to start it from behind.

Pruning

This is done on tender shoots. When they have produced 4-6 pairs of leaves, shorten them to 1-2 pairs. This continuous work is the secret to dense stakes and clouds of vegetation.

Tying & bending

Young branches are flexible, but they lignify and become stiff very quickly.
Apply wire in summer to branches that are still green/brown. Check it every 3-4 weeks: the wrinkled bark hides the incising wire well, risking deep scars if you forget.

Diseases and pests

• Red spider mite: The No. 1 enemy in the house. If leaves yellow and fall off, check for tiny spider webs underneath.
• Mealybug: Hides on branches and under leaves.
• Root rot: If you water too much and the soil does not drain. Leaves turn black and floppy.

Winter & protections

As mentioned, it does not tolerate frost.
It absolutely must be protected. If you live in the South in warm coastal areas, it can stay outside sheltered, but in the North it is an indoor or warm greenhouse plant. If it loses all of its leaves in winter due to a cold or dry spell, don't despair: reduce water and wait until spring, it will often rebloom from old wood.

Annual calendar

• January-February: Bright location indoors, pest control.
• March-April: Awakening, start light fertilization.
• May-June: Moving outside, repotting, pruning.
• July-August: Strong growth, abundant water, stapling.
• September: Retreat indoors (in the north) before nights cool off.
• October-December: Indoor maintenance, misting.

Useful products for this bonsai

• Akadama Hard Quality (Ideal substrate)
• Hanagokoro Organic Fertilizer (Balanced nutrition)
• Plastic saucer (To create moisture with clay)
• Coppered aluminum wire (For shaping the branches)
• Oblique clippers (For clean cuts)
• Acaricide (Against red spider mite in the home)

Tamarind Tree Frequently Asked Questions

Why are the leaves closed even during the day?
If they close with the sun, the plant is in distress: it is thirsty or has taken a cold/heat stroke. It is a defense mechanism to reduce transpiration. Check the soil right away.

Can I keep it outside in winter if I cover it?
In the North, no, not even with nonwoven fabric (TNT). If the temperature goes below freezing, it dies. In the South, in locations sheltered from the wind, it can make it with TNT, but it will probably lose all its leaves.

Why does it lose its inner leaflets?
Lack of light. The Tamarind tree wants lots of light. If the inner branches are in shade, the tree will let them dry out. Thin the foliage or turn the pot often toward the light.