Furry cacti are a diverse group characterized by a distinctive layer of hair, wool, or bristles. These unique coverings give the plants a soft, often whimsical appearance that sets them apart from their spiny relatives.
Why Cacti Develop “Fur”
The woolly or hairy covering on certain cacti serves several purposes, enabling them to thrive in harsh environments. This specialized growth, which is actually a type of modified spine, protects the plant from intense sunlight and harmful UV radiation. The dense “fur” also acts as insulation, shielding the cactus from extreme temperatures.
Beyond temperature regulation, the hairy coating helps reduce water loss by slowing down air movement across the plant’s surface. Some cacti can even collect dew or atmospheric moisture within their woolly coats. The dense hairs also provide a defense against herbivores, often concealing sharp spines.
Common Furry Cactus Varieties
One of the most recognizable is the Old Man Cactus, Cephalocereus senilis, native to Mexico. This columnar cactus is famous for its long, shaggy, white hairs that can grow up to 8 inches, giving it the appearance of an elderly figure. While young plants are covered in silvery-white fur, mature specimens may lose some of this dense covering. In the wild, it can reach impressive heights of 16 to 50 feet, though it typically stays much smaller in cultivation.
Another popular type is the Bunny Ear Cactus, Opuntia microdasys, known for its flat, pad-like segments that resemble rabbit ears. Instead of traditional sharp spines, this cactus is covered in clusters of tiny, barbed bristles called glochids, which can easily detach and cause skin irritation. These glochids are usually yellow or white, giving the plant a polka-dot appearance. This species forms dense shrubs, often growing 1 to 2 feet tall.
Espostoa lanata, often called the Peruvian Old Man Cactus or Cotton Ball Cactus, hails from the high altitudes of the Andes Mountains. This columnar cactus can grow up to 16 feet tall in its natural habitat, covered in dense white woolly hairs that hide sharp spines.
Some Mammillaria species, such as Mammillaria bombycina or Mammillaria hahniana (Old Lady Cactus), also feature woolly areoles or bodies. These typically smaller, often globular or cylindrical cacti, can form clumps and produce white, hair-like spines or woolly coverings. The Old Lady Cactus, for instance, has spherical stems covered in white spines, growing up to about 5 inches wide.
The Peruvian Old Lady Cactus, Oreocereus celsianus, also known as Old Man of the Andes, is a columnar cactus with stems thickly covered in white woolly hair and yellowish spines. Native to the Andes at high elevations, this species can grow up to 10 feet tall in the wild, forming clumps.
Caring for Your Furry Cactus
Furry cacti generally require abundant bright, direct sunlight, ideally receiving 6 or more hours daily. Adequate light encourages the growth of longer and thicker hairs, which is a key characteristic. For indoor cultivation, placing them in a south-facing window is often beneficial.
Well-draining soil is crucial for furry cacti to prevent root rot, mimicking their natural arid habitats. A pre-made cactus soil mix or a blend of sand, perlite, and potting soil that drains quickly is suitable. Unglazed terracotta pots with drainage holes are recommended as they allow excess moisture to evaporate through the pot walls.
Watering should be infrequent, allowing the soil to dry completely between applications. During the growing season, typically spring and summer, water thoroughly but then allow the soil to become completely dry before watering again. Avoid getting the “fur” wet, as this can lead to matting, rot, or fungal issues; bottom watering or careful top watering directly to the soil is best.
Furry cacti prefer temperatures between 65 to 90 degrees Fahrenheit during their active growth period. During the cooler, dormant months of winter, temperatures between 45 to 65 degrees Fahrenheit are generally ideal. High humidity should be avoided, as these plants thrive in dry, well-ventilated conditions. Light feeding with a low-nitrogen, balanced cactus fertilizer can be done monthly during the growing season, but should be withheld in winter.
Important Considerations and Handling
Despite their soft appearance, many furry cacti conceal sharp spines. For example, the Old Man Cactus has formidable yellow central spines hidden by its white coat. Opuntia microdasys is covered in tiny, barbed glochids that easily detach and embed in the skin, causing irritation. The “fur” is generally not soft and can cause discomfort.
When handling furry cacti, it is advisable to use thick gloves, tongs, or folded newspaper to protect your hands from hidden spines or glochids. This minimizes the risk of irritation or injury. For any glochids that do embed, covering the affected area with Elmer’s glue, allowing it to dry, and then peeling it off can help remove them.
The dense woolly coating can sometimes hide pests like mealybugs, making infestations difficult to detect. Regular inspection of the plant, including gently parting the fur, is important to catch any issues early. If pests are found, treatment can be tricky due to the fur, often requiring careful application of horticultural oils or systemic insecticides.