We’ve recently been experimenting with germinating the Amazonian plant ‘Cebil’, hence thought we’d put together this guide explaining how to grow Anadenanthera colubrina from seed. Note that this approach should also work well for the cultivation of the very similar species Anadenanthera peregrina.
A fascinating species prized as an ornamental and with a rich heritage of indigenous use in its natural habitat, colubrina is a knotty or thorny tree of the Southern Andes and is part of the Fabaceae family. Reaching up to approximately twenty metres in height once fully mature, colubrina‘s deep-green, ferny foliage contrasts well with the plant’s fantastic burgundy to brown, thinly flat seed pods (up to thirty-five centimetres long – and toxic!). The plant’s beauty is further enhanced by its fragrant, pale yellow-white-whitish spherical flowers, which bloom throughout the summertime in USDA Hardiness Zones 8-10.
Read on to learn how to grow Anadenanthera colubrina from seed!
How to Grow Anadenanthera colubrina from Seed
- Anadenanthera colubrina seeds
- Coco coir
- Growing containers
- Mini-greenhouse/humidity chamber (we recycle the top halves of plastic water bottles)
- Mist/spray bottle
- Organic compost
- Organic fertiliser
- Peat substitute
- Potting soil
Method – Germination:
- Soak your Anadenanthera colubrina seeds in room temperature water for between one and twelve hours. After a while, you’ll notice that the burgundy-brown-coloured outer seed coats start to soften and slip off of the seed proper. Gently remove and dispose of these and you’ll have a much greater chance of avoiding rot during the whole process! The seeds will take different amounts of time to shed their coats, so keep soaking if they’re still hard – just make sure to rinse all of the organic debris from the naked seeds prior to sowing them.
- As this species has a tendency toward rotting, we find it’s best to use a non-organic potting mix of equal parts sand (coarse works fine for us) and perlite or vermiculite. Pasteurise or sterilise this if you like (we don’t usually bother), mix it all up as evenly as possible and then fill your growing container. You can also get good results by simply germinating the seeds on a damp paper towel left in a sealed plastic bag.
- Mist the surface of the mix with water and allow it to drain so it’s damp rather than soaking. If going the paper towel route, use the spray bottle to dampen it.
- Mimic the natural dispersal of the seeds by placing them flat on their sides on top of the growing medium. We’ve experimented with various other approaches (burying them at various depths, edge-on, etc.) and found this to achieve the best results.
- Lightly cover the seeds with a thin layer of perlite or vermiculite, to help retain moisture while still allowing good ventilation.
- Position the container somewhere well-lit but out of direct sunlight, mist and cover with your mini-greenhouse. Optimum germination is achieved at a soil temperature of roughly 21-22°C / 69-72°F and an ambient temperature of approximately 23-24°C / 73-75°F.
- Ventilate the container daily, to avoid encouraging fungus, etc. via the build up of stale air. Fresh air will also aid the plant to photosynthesise efficiently.
- (Optional:) Although we’ve found it to be unnecessary in our climate (at least, for the first few days when growing indoors using a mini-greenhouse), general advice for successful colubrina germination is to lightly mist the growing medium on a daily basis.
- Healthy, fresh seeds should begin to germinate within a week or so (perhaps two). The seeds illustrating this guide were photographed after only five days!
- When you can see the seed coat starting to split (as in the photo directly above this), it’s possible to further reduce the risk of rotting and generally help things along by manually removing it. Carefully split the seed coat so that you can gently remove the seedlings without damaging their new leaf growth. We recommend using either your fingers, a scalpel or tweezers for this – it also helps to soften the seed coat by wetting it a few minutes prior to removal.
- (Optional:) Use a small electric fan to make the seedlings sway gently. The motion caused by an indirect draft will help to strengthen their stems, but never point the fan directly at them – unless you want to risk snapping their stems!
- Once the seedlings are roughly fifteen to twenty-five centimetres high, they’re ready to be transplanted to individual containers.
Anadenanthera colubrina germination experiments
Method – Transplanting & Ongoing Care:
- Once the colubrina seedlings are a minimum of fifteen centimetres tall, it’s time to transplant them to larger containers. We recommend planting using a well-drained mixture of two parts ‘standard’ potting soil, two parts sand and one-part organic compost. An equal mix of commercial cactus mix and perlite also works well.
- Situate the plants somewhere in full to partial sun. If growing outdoors, choose a location that is unlikely to suffer frost, else over-winter the plants indoors until they are at least a few metres tall.
- Growth will be rather slow for the first year or two, but provide a suitable habitat and sufficient watering and your plants will soon start to become more confident! Water regularly in adequate amounts, but make sure to allow the soil to dry out completely between applications. Remember: too much (or too little) water is your enemy!
- Lightly apply a monthly dose of organic fertiliser over the summer.
- Once the plants are two years old, re-pot into larger containers (or directly into the ground, if your climate’s suitable). You can use a richer growing medium now that the colubrina is more mature; half peat substitute, a quarter coco coir and a quarter perlite is a good starting point. You can improve drainage by lining the lower few centimetres of the containers with (washed) gravel, small rocks or broken pieces of terracotta pots. It’s also a good idea to use a one-centimetre-deep gravel top layer too.
- From now on, the plants should start to greatly increase in vigour, provided you treat them well and satisfy all of their essential needs! If you’re really lucky, your colubrina may even start to produce flowers once they’re two or three years old.