Dendrobium Anosmum

Dendrobium anosmum blooms along bare canes in spring, creating cascading waterfalls of purple flowers. This orchid, often called the unscented dendrobium or the “Sanggumay” in the Philippines, is a favorite among growers for its spectacular display and ease of care. If you have been searching for a show-stopping orchid that doesn’t demand a greenhouse, this is your plant.

In this guide, we will walk you through everything you need to know about growing and blooming this specific species. We will cover light, water, temperature, and the tricky “rest period” that triggers those amazing flowers.

Understanding The Unique Growth Cycle

To be successful with this orchid, you have to think like it does. It is a deciduous species, meaning it drops its leaves in the winter. This is not a sign of death; it is a sign that it is preparing to bloom.

This plant is native to areas with distinct wet and dry seasons. You must replicate this cycle in your home to get flowers. If you treat it like a typical phalaenopsis orchid, you will likely get leaves but no blooms.

Key Characteristics Of The Plant

Canes: The pseudobulbs can grow up to 3-4 feet long. They are thick and fleshy when young, but become ribbed and bare as they age.
Flowers: Blooms are usually lavender to deep purple, though white and pink variants exist. They are large, fragrant (despite the name meaning “without smell”), and last for about a month.
Growth Habit: It is an epiphyte, meaning it grows on trees in the wild. You should mount it or put it in a basket with excellent drainage.

Let us get into the specifics of daily care. This section covers the essential elements that keep the plant healthy throughout the year. Remember, the care changes drastically depending on the season.

Light Requirements For Abundant Blooms

This orchid loves light. In fact, it needs more light than most indoor orchids to thrive. Insufficient light is the number one reason this plant fails to bloom.

Place it in the brightest window you have, preferably a south or west-facing window. If you are growing under lights, aim for about 2000-3000 foot-candles.

You want the leaves to be a medium green with a slight yellowish tint. If the leaves are dark green, they are not getting enough energy. If they are yellow with red spots, they are getting too much.

Watering And Humidity

Watering is where most people get confused. The rule is simple: water heavily during the growing season, and almost stop during the winter rest.

Spring/Summer: Water 2-3 times a week. The media should never completely dry out, but it should not be soggy either.
Fall: Gradually reduce watering as the days shorten.
Winter: Water only once every 2-3 weeks, or just mist the canes lightly to prevent shriveling.

Humidity is important. Aim for 50-70% humidity during the summer. You can use a humidity tray or a room humidifier to achieve this.

Temperature And Air Circulation

This is a cool to intermediate growing orchid. It does not like extreme heat. The ideal summer temperatures are between 65°F and 85°F (18°C – 29°C).

The magic happens in the fall and winter. To trigger buds, you need a significant temperature drop. Night temperatures must fall to between 50°F and 55°F (10°C – 13°C) for several weeks.

This cool period is essential. Without it, the buds will not form. Make sure there is good air movement to prevent fungal issues, especially when it is cool and damp.

Potting Media And Repotting

Because this orchid has long, trailing canes, it is often best grown in a hanging basket or mounted on a slab. This allows the canes to cascade naturally.

If you choose a pot, use a coarse mix. Fir bark, perlite, and charcoal are good choices. The roots need to dry out quickly after watering.

Repotting should only be done every 2-3 years, or when the media has broken down. Do this in the spring when new growth begins.

Soak the roots to make them pliable.
Remove the old media carefully.
Cut away any dead or hollow roots.
Place in a new basket or pot, securing the plant firmly.
Do not water for 3-4 days to allow cuts to callus over.

Fertilizing Schedule

Fertilizer is crucial for growth, but you must change your approach based on the season. Over-fertilizing during the rest period can cause root burn.

During the active growing season (spring and summer), feed with a balanced fertilizer like 20-20-20. Use it at half strength every other watering.

In the fall, switch to a high-phosphorus fertilizer like 10-30-20. This encourages bud formation. Stop fertilizing entirely during the winter rest.

How To Trigger Blooming

This is the most critical part of the guide. If you follow these steps, you will see flowers. If you skip them, you will only see leaves.

The blooming process relies on three factors: light, temperature, and water. You need to manipulate all three.

Stop Watering: In late October or November, drastically reduce water. Let the canes wrinkle slightly.
Drop Temperatures: Move the plant to a cool room, porch, or garage where night temps are in the 50s (Fahrenheit).
Maximize Light: Give it as much direct winter sun as possible.
Watch for Buds: After 4-6 weeks of this treatment, you should see small bumps forming at the nodes of the bare canes.
Resume Care: Once buds appear, increase water slightly and move the plant back to a warmer spot to enjoy the flowers.

Be patient. The buds take time to develop. Once they start, they grow quickly.

Common Problems And Solutions

Even with great care, you might run into issues. Here are the most common problems and how to fix them.

Bud Drop

If your buds turn yellow and fall off, it is usually due to stress. This can be caused by sudden temperature changes, drafts, or inconsistent watering.

Once buds appear, do not move the plant. Keep the environment stable. Avoid getting water on the buds themselves.

Black Spots On Canes

This is often a fungal issue caused by poor air circulation or water sitting in the leaf axils. Improve airflow and avoid watering late in the evening.

You can treat with a copper-based fungicide. Remove any severely affected leaves.

No Blooms

This is the most common complaint. It almost always comes down to a lack of a winter rest. If you did not drop the temperature or reduce water, the plant will not bloom.

Also, check your light levels. If the plant is in a dark corner, it will not have the energy to produce flowers.

Propagation Methods

Once you have a healthy, large plant, you can propagate it. The easiest way is by division. This is best done in the spring when new growth is starting.

You need to have at least 3-4 canes per division to ensure the new plant has enough energy to survive.

Remove the plant from its pot.
Cut the rhizome with a sterile knife.
Ensure each division has a healthy root system.
Pot them up separately.

Another method is taking keiki (baby plants) that sometimes form on the canes. Wait until the keiki has roots at least 2 inches long before removing it.

Frequently Asked Questions

Here are some quick answers to common questions about this orchid.

Why Is My Dendrobium Anosmum Dropping Its Leaves?

This is normal in the fall and winter. It is a deciduous orchid. If it drops leaves in the summer, you likely have a root rot problem from overwatering.

How Long Do The Flowers Last?

Typically, the blooms last for 4-6 weeks. Keeping the plant away from direct heat sources and drafts will prolong the flower life.

Can I Grow This Orchid Indoors?

Yes, but you need a bright window and a way to provide cooler night temperatures in the fall. A spare room or a windowsill near a cold window works well.

What Is The Best Potting Medium?

Large fir bark mixed with perlite is ideal. You want the mix to be chunky and airy. Sphagnum moss retains too much water for this species.

Is Dendrobium Anosmum Fragrant?

Despite the name “anosmum” meaning without smell, many varieties have a sweet, raspberry-like fragrance, especially in the morning. The scent is subtle but pleasant.

Final Care Checklist

To wrap up, here is a quick summary of what you need to do to keep your plant happy.

Summer: Water often, fertilize weekly, keep it warm and bright.
Fall: Reduce water, stop fertilizer, expose to cool nights.
Winter: Keep it dry and cool, provide maximum light.
Spring: Watch for buds, resume watering, enjoy the flowers.

Growing this orchid is a rewarding experience. The sight of those bare canes covered in purple blooms is worth the effort. Just remember to give it that cool, dry rest in the winter, and it will reward you every spring.

If you have been struggling with this plant, try adjusting your winter care routine. It is often the only thing standing between you and a spectacular floral display. Happy growing.