Say it: MEL-oh-cactus. Common names: melon cactus, Turk's cap cactus.
Where it grows
The Caribbean islands, Mexico, Central America and eastern Brazil, usually near the coast in hot, humid lowlands. Melocactus matanzanus comes from Matanzas province in Cuba; M. pachycanthus from the dry caatinga of Bahia, Brazil.
Size and growth
A ribbed green globe that, on reaching maturity, stops growing and builds a cephalium: a dense cap of wool and red-orange bristles on top. From then on only the cap grows taller, which is what makes old plants look like they're wearing a fez. M. matanzanus is the dwarf of the genus, forming its cephalium at just 3–4 inches across and 5–8 years old; M. pachycanthus is larger with heavy spines.
Flowers and fruit
Small pink flowers push out of the cephalium in summer, followed by shiny pink, finger-shaped fruits packed with seed. Plants fruit for years once the cap forms.
Care
- Light: bright, with some shade in the hottest sun.
- Water: regular in warm weather; unlike most cacti, they dislike long bone-dry spells. Reduce, but don't stop, in winter.
- Soil: gritty, fast-draining.
- Cold: tropical. Keep above about 55°F; cold and wet together is fatal.
From seed
Easy. Germination in 7–21 days with warmth. Seedlings grow steadily and are among the most satisfying cacti to raise, since the cephalium arrives in a reasonable number of years.