Mammillaria compressa DC.
Mother of Hundreds
Cactus cirrhifer, Cactus longisetus, Cactus squarrosus,
This species is native to Mexico. It occurs from Hidalgo northwards to Tamaulipas and westwards to Queretaro at elevations from 3,280 to 7,350 feet (1,000 to 2,240 m).
Mammillaria compressa is a clump-forming cactus with cylindrical to club-shaped stems with spines that vary in length and arise from conical tubercles. It readily offsets, forming in time as large a large clump. The stems are gray-green to blue-green, often with tufts of white hair and bristles in the axils. They are up to 10 inches (25 cm) long and 4 inches (10 cm) in diameter. The spines are usually chalky white with brown tips. Each areole bears 4 to 6 radial spines, with the lower being longer. Central spines are absent. Flowers are bright purple-pink, up to 0.6 inches (1.5 cm) in diameter, and appear in spring, forming attractive rings around each stem. Fruits are red, club-shaped, and contain brown seeds.
The specific epithet "compressa (kom-PRESS-uh)" is a feminine form of "compressus," meaning "compressed," and refers to the growth habit of the species.
How to Grow and Care for Mammillaria compressa
Light: Plant this cactus in an area of your garden that receives 4 hours of direct sunlight a day. If you are growing M. compressa indoors, place it near the brightest window in your home or office to ensure your cactus gets enough light. If possible, place the pot on the balcony or in the garden for extra light from spring to fall.
Soil: M. compressa requires a soil mix that provides root aeration and good drainage, whether grown outdoors or indoors. Use a commercial cactus potting mix, or create your own.
Temperature: This cactus is heat tolerant but is not a cold-hardy plant. M. compressa can withstand temperatures as low as 25 °F (-3.9 °C). USDA Plant Hardiness Zones 9b to 11b, 25 to 50 °F (-3.9 to 10 °C).
Watering: From spring to fall, water deeply and wait for the soil to dry before watering again. Never let the pot sit in water. Suspend watering in the winter.
Fertilizing: M. compressa can benefit from fertilization during the growing season. Apply a water-soluble fertilizer for cacti and other succulents. Suspend feeding during the winter when the plant goes dormant.
Repotting: Repot every two or three years into a slightly larger pot. The best time to repot your M. compressa is late winter or early spring, but the repotting process can be done almost any time of the year.
Propagation: There are two easy ways to propagate M. compressa: by seeds or by dividing offsets. The best time to remove offsets is in spring and summer. Sow the seeds in late spring or summer.
Learn more at How to Grow and Care for Mammillaria.
Toxicity of Mammillaria karwinskiana
M. compressa is considered non-toxic to both humans and pets.
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