Aerangis Biloba

If you’re looking for a truly elegant and manageable orchid, you should consider the Aerangis biloba. This exquisite orchid species is a fantastic choice for both new and experienced growers, offering delicate beauty without overwhelming demands.

Its common name, the Two-Lobed Aerangis, comes from the unique notch at the tip of its leaves. Native to West and Central Africa, it grows as an epiphyte on tree branches in humid forests. This gives us big clues about how to care for it successfully at home.

Let’s get to know this plant a bit better. Understanding its natural habitat is the first step to keeping it thriving on your windowsill.

Origin and Natural Habitat

Aerangis biloba is found from Sierra Leone all the way to Uganda and Angola. It lives in tropical rainforests, typically at lower altitudes.

In the wild, it attaches itself to tree bark. This means its roots are exposed to air and light, and they dry out quickly after rain. It enjoys dappled sunlight, high humidity, and good air movement all day long.

Physical Characteristics

This orchid is known for its graceful appearance. Here are its key features:

Leaves: It has 4 to 6 dark green, leathery leaves arranged in a fan. Each leaf is about 6 inches long and has that distinctive bilobed (two-lobed) tip.
Roots: The roots are thick, silvery-gray, and covered in velamen. This sponge-like layer absorbs water and nutrients. They often sprawl outside the pot.
Flowers: The blooms are the real show. A single flower spike can carry 5 to 15 pure white, star-shaped flowers. Each has a long, slender nectar spur that can be up to 5 inches long.
Fragrance: The flowers emit a sweet, citrusy scent, usually strongest in the evening to attract moth pollinators.

Light Requirements

Getting the light right is crucial. Too much sun will scorch the leaves, while too little will prevent flowering.

Provide bright, indirect light. An east-facing window is often perfect.
A lightly shaded south or west window can also work if you use a sheer curtain as a filter.
The leaves should be a healthy medium green. If they turn yellowish, the light is too strong. If they become very dark green and the plant doesn’t bloom, it needs more light.

Temperature and Humidity

This orchid prefers conditions that mimic a warm, humid forest. It’s considered a warm to intermediate grower.

Daytime Temperatures: Aim for 70°F to 80°F (21°C to 27°C).
Nighttime Temperatures: A drop to 60°F to 65°F (15°C to 18°C) is beneficial, especially in fall to initiate flower spikes.
Humidity: This is non-negotiable. You need to maintain 60% to 80% relative humidity. This can be the trickiest part for indoor growers.

To increase humidity, you can use a humidifier, place the pot on a tray of pebbles with water (keeping the pot above the water line), or group it with other plants. Misting can help, but it’s not a substitute for proper ambient humidity and can lead to fungal spots if overdone.

Watering and Feeding

Watering is where many orchid troubles start. Remember, this plant is used to frequent rains followed by quick drying.

Water Thoroughly: When you water, drench the roots completely until water runs freely from the pot.
Let it Dry: Allow the roots to become almost dry before watering again. The silvery roots will turn green when wet.
Frequency: This could mean watering every 2-3 days in warm weather or once a week in cooler, dull weather. Always check the roots, not the calendar.
Water Quality: Use room-temperature rainwater, distilled water, or reverse osmosis water if possible. Tap water with high mineral content can damage the roots over time.

For feeding, less is more. Use a balanced, water-soluble orchid fertilizer at 1/4 to 1/2 the recommended strength.

Fertilize every other watering during the active growing season (spring and summer).
Reduce feeding to once a month in fall and winter.
Flush the pot with plain water once a month to prevent harmful salt buildup from the fertilizer.

Potting and Mounting

Because of its need for air around the roots, traditional potting soil is a death sentence. You have two excellent options.

Option 1: Mounting

This is the most natural way to grow Aerangis biloba. You attach the plant to a piece of cork bark, tree fern plaque, or even a branch.

Pros: Superb air flow, roots dry quickly, mimics nature.
Cons: Requires more frequent watering (sometimes daily) and higher humidity.
How to Mount: Place a small pad of sphagnum moss around the roots, secure the plant to the mount with fishing line or nylon thread. The roots will eventually attach themselves.

Option 2: Potting in a Basket

A slatted wooden or plastic basket is the next best thing to mounting.

Media: Use a very open mix. Large chunks of bark, charcoal, and horticultural perlite work well. You can include a little moss to retain some moisture.
Pot Choice: Always use a pot with many holes for drainage and air flow. Clear pots let you monitor root health easily.

Repot or remount only when the media breaks down (becomes mushy) or the plant outgrows its space. The best time is just as new roots begin to appear, usually after flowering.

Encouraging Blooms

A healthy Aerangis biloba will typically bloom in late summer or fall. If yours is shy, check these factors.

Light: Ensure it’s getting enough bright, indirect light.
Temperature Drop: A slight cool-down at night (by about 10 degrees) in the weeks leading up to bloom season can trigger spiking.
Proper Feeding: A consistent, light feeding schedule during growth builds energy for flowers.
Root Health: Blooms come from a happy root system. Check that your roots are plump and firm, not brown and mushy.

Once a flower spike appears, avoid moving the plant to much. The buds can abort if the light direction changes dramatically. The flowers themselves can last for several weeks, filling your space with their lovely fragrance.

Common Problems and Solutions

Even with great care, issues can pop up. Here’s how to troubleshoot.

Yellowing Leaves: Often a sign of too much direct sun. It can also indicate overwatering or old age (bottom leaves naturally yellow and fall off over time).
Brown Leaf Tips: Usually caused by low humidity, salt buildup from fertilizer, or inconsistent watering.
No Flowers: The most common culprits are insufficient light, lack of a temperature differential, or a plant that is too young or stressed.
Soft, Mushy Roots: This is root rot from overwatering or poor drainage. You’ll need to remove the plant from its pot, cut away all soft roots with sterile tools, and repot in fresh media.
Pests: Watch for scale, mealybugs, and spider mites. Treat early with insecticidal soap or horticultural oil, ensuring you cover the undersides of leaves.

Propagation Methods

You can propagate Aerangis biloba, though it’s not the fastest process. The main method is by removing keikis (plantlets).

Sometimes, a keiki will form on an old flower spike or at the base of the plant. Let it grow until it has several roots that are at least 2-3 inches long. Then, you can carefully cut it away from the mother plant with a sterile knife and pot or mount it on its own. Treat it as a seedling, with slightly higher humidity and careful watering.

FAQ Section

How often does the two-lobed aerangis orchid bloom?
Typically once per year, in late summer or fall. A very mature, happy plant may occasionally produce a second spike.

Can I grow Aerangis biloba in a terrarium?
Yes, a well-ventilated terrarium or orchidarium can provide the perfect humid environment. Just ensure there’s enough air movement to prevent fungal issues.

Why are the leaves on my biloba orchid splitting?
Splitting leaves are usually caused by physical damage or, more commonly, by allowing the plant to get too dry and then overwatering, causing the leaves to swell and tear. Try to maintain more consistent moisture.

Is this type of aerangis fragrant?
Yes, its white flowers are known for their pleasant evening fragrance, often described as sweet and citrusy.

Growing Aerangis biloba is a rewarding experience that connects you to the rainforests of Africa. Its elegant form and stunning floral display are well worth the attention to detail it requires. By focusing on high humidity, bright indirect light, and a careful watering routine, you’ll be able to enjoy this exquisite orchid species for many years. Pay close attention to what the leaves and roots are telling you, and you’ll have a thriving plant.