Natural Growing Conditions
Psychotria viridis is native to the Amazonian lowlands, but is also cultivated throughout northern South America and much of Central America. It is an evergreen tropical tree or large shrub growing in full sun to half shade. It has large (up to 24cm) leaves, which are oval with pointed tips. Its small brown seeds are shed from red berries. It usually grows in very rich and fertile soils.
Growing from Seed
Everybody seems to agree that it is very difficult to germinate Psychotria viridis seeds. I’ve heard of so many failures, including someone using a vaporizer as a propagator to heat the seed(!?). Crazy! I have never tried though, it just doesn’t seem worth the trouble. I ended up buying a rooted cutting to save myself the hassle. If you really must grow from seed, I would recommend using a variation of this technique:
- Soak the seeds for 15 minutes in a mild bleach solution.
- Rinse off the bleach with sterile water.
- Soak the seeds in sterile water for 24 hours.
- Plant the seeds 8mm deep in vermiculite or a mixture of vermiculite and potting compost.
- Water from below until the growing medium is moist throughout.
- Place in a heated propagator away from direct sunlight and wait.
Growing from Cuttings
Cuttings, on the other hand are easy. Psychotria viridis clones well using a standard leaf cutting technique, so all you need is a fresh leaf to get you started.
Remove a large leaf from the plant complete with a full petiole (leaf stem). Take hold of the leaf by its peliole, bend it away from the stem and gently pull in the same direction until it breaks. The petiole should have a short tail which has pulled away from the stem. This will ensure that there is a large amount of cambium layer present, which is essential for root development.
Lay the leaf on a flat surface and cut it in half horizontally with a sharp sterile blade. Removing the top half of the leaf will cut down on evaporation from the leaf and retain moisture before roots form.
Prepare a free draining growing medium. Something like equal parts vermiculite, sand and potting compost would be about right. You may wish to 100% inorganic components to prevent moulds forming. Fill pots or seed trays with your growing medium, making small holes every 5-7cm with a matchstick or similar pointy thing. Place the leaves in the holes, petiole down, cut edge up. The leaves should be planted deep enough so that the petiole and about 0.5cm of the lower part of the leaf are covered.
Water, leave to drain, and place inside a heated propagator. If you have no propagator, place inside sandwich bags and leave somewhere warm. The cuttings should receive bright light, but not direct sunlight. Mist daily with a pump spray or similar. Water regularly, but ensure the growing medium never becomes waterlogged. If mould appears, treat with Cheshunt Compound, or any fungicide. Also remember to feed with fertilizer as per instructions on the pack.
The cuttings should be slowly acclimatized to drier, brighter conditions as soon as possible. When they are well established or overcrowded, they can be potted up individually.
Unfortunately, I cannot give any advice on growing Psychotria viridis to maturity. The only plant I have grown dropped all its leaves and quickly died. The whole process took about a fortnight. I believe it was due to overwatering and large day/night temperature fluctuations. Que Sera Sera.
Since the above was written, there have been further developments with my dead Psychotria viridis plant. It was left on a cold bedroom windowsill throughout Winter. The soil got a bit moldy and eventually dried out. The growing tip was brown and dead. I gave up hope, but somehow or another, I never got round to throwing it in the compost bin. At the beginning of Spring, I noticed that the stem was still green. Just for the sake of it really, I decided to water it one more time, with the addition of some Cheshunt compound to stop the mould coming back. Within a week or two, new shoots had appeared on four nodes. It came back from the dead. It is currently sitting on a warm bathroom windowsill, being nursed back to health.