The most popular Trichocereus species, the Trichocereus pachanoi (also known as the San Pedro cactus), is indigenous to South America.
This multi-stemmed Cactaceae plant features light/dark green stems, with up to seven spines in each aureole, though cultivated varieties are often spineless. The plant flowers at night and is extremely fragrant. The cactus plant itself can reach up to 5.9 ft in height.
Due to its widespread presence and popularity, the Trichocereus pachanoi is known by as many as 25 different names in Spanish alone, such as ‘wachuma’, ‘giganton’, ‘andachuma’, and ‘huachuma’.
The genus Trichocereus was merged with Echinopsis—the two are used interchangeably today to refer to the San Pedro cactus. Additionally, due to its deep similarities with the Peruvian torch cactus, both plants are often confused with being the same.
Types Of Trichocereus Species
1,000 Types of Cacti [With Pictures]
Though the Trichocereus species is low maintenance, the following information can help in better cultivation.
Trichocereus cactus, like most cacti, prosper when exposed to direct sunlight. However, this is the case only after the first year—seedlings require some amount of shade as they may suffer sunburn in direct sunlight.
In the summer months, Trichocereus plants grow best in light shade.
If you overwinter your plants in the colder months, ensure that you gradually increase your plant’s exposure to direct sunlight, instead of all at once, as this could also cause sunburn.
6-8 hours of sunlight a day is good; if you’re growing them indoors, 14-16 hours of lighting is necessary.
The Trichocereus species cactus goes dormant in the winter months, as most of its cacti cousins do, which means that you should refrain from watering them between the months of October and April to reduce the possibility of rot.
In the other months, water only when the soil is completely dry to the touch, and just enough to make the soil moist, all the while ensuring proper drainage of water. Allow sufficient drying time between watering periods.
A mushy cactus is a sign of overwatering.
Trichocereus species cacti grow best in slightly acidic, fertile potting soil—good drainage goes without saying!
To reduce the risk of rot, small amounts of humus may be incorporated into the potting mix.
The best option is store-bought cactus/citrus mix; if this is unavailable, mix sand, fine gravel, peat moss, and perlite to make your own cactus potting mix.
In the seedling phase, a small amount of highly diluted fertilizer is healthy, encouraging the plant to grow well. Adult Trichocereus plants can handle larger amounts of fertilizer, though even these should be diluted and only very occasionally fed to the plant.
Many gardeners don’t fertilize their cacti, as over-fertilizing can be quite harmful to the plant. Fertilizer is not a necessity unless you observe your plant not hitting its growth milestones properly.
However, if you do want to fertilize your plant regularly, do so only during the growing season, once a month, feeding it diluted liquid fertilizer or cactus-specific fertilizer.
Plants of the desert, Trichocereus species cacti can tolerate extreme temperatures. The plant can tolerate temperatures as low as 10°C, and even the occasional -9°C, and highs of 38°C and higher.
However, the most ideal conditions for the Trichocereus species plants are around 21°C.
The Trichocereus cactus is prone to certain pests and diseases, such as fungal diseases (characterized by rotting stems), root aphids, mealy bugs, and spider mites.
Another common disease is black spots, a fungal infection. However, this is non-fatal and easily treated.
As mentioned earlier, Trichocereus species cactus plants can reach heights of up to 6 ft, so you may have to cut them to manageable sizes.
Apart from that, rotting, soft stems, pests, and the appearance of dead stems after blooming are all signs that your cactus needs to be cut back.
Trichocereus cactus plants need to be transplanted to bigger spaces once they turn a year old.
As for when to repot your cactus, you need to do so when you see the roots protruding from the container’s bottom. Generally, a rule of thumb is to repot every 2 to 4 years. However, if you fertilize your plant, repotting once in 4 years will suffice.
Repotting should be done during the active growing period—January or February.
Propagating Trichocereus Species Plants
Trichocereus species plants can be propagated via cuttings or seeds.
Cutting is the easier and more effective method of the two. You can make use of a cutting from a full-grown plant. Allow it to form a callous post-cutting, and dry it in a cool location before transplanting.
Once dry and calloused, set in the soil, setting them 2-3 inches deep. After a couple of weeks, roots should develop—you can check this by lightly tugging the plant upwards and checking for resistance, which indicates the presence of roots.
Using seeds, though more uncommon, is still an effective way to grow Trichocereus cacti. Place the seeds just beneath the soil and keep the soil moist during the germination period, maintaining temperatures at around 27°C during the day and 21°C during the night.
Roots develop after a month or so in this process.