Pilosocereus is a genus of cacti native to Mexico, the Caribbean, and Brazil. Containing many different species, Pilosocereus includes both cacti that are commonly used in cultivation and some that are so rare that they're almost unknown outside botanical sources. The most common houseplant in the genus is Pilosocereus pachycladus (also known as the blue column cactus), which large nurseries produce in bulk and sell wholesale.
This desert species has a branched form and grows fairly quickly, often adding between 1 and 2 feet of height a year. Those that flower do so at night and all are most easily identifiable by their attractive blue-green skin, which is complemented by bright yellow spines. Pilosocereus cacti are mostly tree-like, and their flowers are shaped like tubes and grow fleshy fruits. In cultivation, they are planted and grown year-round, mostly in greenhouses due to their large size and need for warmth in the winter. Their name derives from the Latin term for “hairy cereus,” thanks in part to their spiny aureoles, many of which have a golden tint.
Despite their large size, Pilosocereus cacti are commonly cultivated as domestic cacti in tropical areas due to their aesthetic beauty. Gardeners with the correct climate and enough space should consider plants from this genus for their landscape, while others can grow them on a smaller scale indoors.
|Common Name||Column cactus, blue torch cactus, woolly torch cactus|
|Mature Size||6–12 ft. tall, 2–4 ft. wide|
|Sun Exposure||Full sun|
|Soil Type||Sandy, well-drained|
|Soil pH||Neutral to acidic|
|Flower Color||White, white-yellow|
|Hardiness Zones||9–11 (USDA)|
|Native Area||Mexico, South America, Caribbean|
Pilosocereus Cacti Care
Though there are different types of cacti in the Pilosocereus family, they all generally necessitate the same type of care (which is also very similar to most other cacti, too). If you don't live in an extremely warm, desert-like climate, your best bet is probably to grow your pilosocereus cacti indoors, where you can most easily achieve and maintain the proper growing conditions.
Like most cacti, members of the Pilosocereus family need lots and lots of direct sunlight to flourish. The brighter the light, the better, and you should aim for between 10 and 12 hours a day. If you do have a varietal with blue skin, the more sun it gets, the more vibrant the color will be.
When it comes to planting your cacti, arguably the most important factor is a well-draining soil. In order for your Pilosocereus cacti to be happy, they should be kept in a soil mixture that is dry (like a combination of perlite, sand, and limestone) with some organic matter mixed in. In order to aid in drainage, you can also plant your cacti in a terracotta or clay pot, which will help wick additional moisture away from the soil and prevent rot.
Weekly watering should be sufficient for the water needs of this cacti family. They need a solid supply of water during the summer, but make sure not to overwater them, which can cause rot. A good test is to stick your finger into the soil about a few inches down. If the soil is dry there, it's likely time to water.
Temperature and Humidity
Being a desert dweller, the Pilosocereus cacti family loves hot heat. They prefer consistent temperatures above 70 degrees Fahrenheit and can tolerate triple-digit heat, so there's no need to worry if things are getting too warm for your cactus. On the other hand, Pilosocereus cannot withstand frost, cold, or freezing temperatures, so you should make sure its environment doesn't dip lower than 50 degrees Fahrenheit.
This cactus family is already known to grow quickly, but a bit of added fertilizer can't hurt—in fact, it may help them grow even faster. Complementing their watering with a diluted liquid fertilizer once every few weeks during the growing season for best results. Be sure to use a balanced fertilizer like a 20-20-20 that's been diluted so it doesn't burn your cactus.
Pilosocereus Cacti Varieties
There are many interesting Pilosocereus cacti varieties, including the previously-mentioned Pilosocereus pachycladus (which is also listed by some sources as Pilosocereus azureus). For instance, Pilosocereus gounellei (also known as the Xique-xique cactus), is another Brazilian native with an interesting forked branching habit that can grow up to 14 feet tall. Yet another varietal, the wooly torch cactus (Pilosocereus leucocephalus) has dense white hairs that grow in between its spines and all over its columns.
Propagating Pilosocereus Cacti
The best way to propagate a Pilosocereus cactus is with cuttings. You can cut off the top of the plant once it’s begun to mature and replant it as the bottom of a new one. Once the top-cuts have rooted, they should flower fairly early on in their lives. Cutting off the tops of existing plants is a good way to ensure flowering in your cacti.
Common Pests and Diseases
While these cacti don't have many serious pest or disease issues, there are a few common inflictions you should keep an eye out for. Most frequently, you'll notice an issue with mealybugs, which can affect nearly every part of the plant, from the roots to the ribs. To treat, inspect the entire plant, and use a brush or high-pressure water hose to remove as many of the bugs as you can from the plant. Then, treat it with an insecticide until all traces of infection have vanished.