Scientific Name
Parodia mammulosa (Lem.) N.P. Taylor
Common Name(s)
Tom Thumb Cactus, Tom Thumb, Lemon Ball Cactus, Lemon Ball
Synonym(s)
Parodia mammulosa subsp. mammulosa, Echinocactus mammulosus, Echinocactus floricomus, Echinocactus hypocrateriformis, Echinocactus submammulosus, Malacocarpus mammulosus, Notocactus cristatoides, Notocactus erythracanthus, Notocactus floricomus, Notocactus hypocrateriformis, Notocactus macambarensis, Notocactus mammulosus, Notocactus megalanthus, Notocactus paulus, Notocactus ritterianus, Notocactus roseoluteus, Notocactus submammulosus, Parodia submammulosa, Ritterocactus mammulosus, Ritterocactus megalanthus
Scientific Classification
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Notocacteae
Genus: Parodia
Description
Parodia mammulosa is a cactus with a globose stem with a dark green surface and a flattened apex. The stem grows up to 6 inches (15 cm) in diameter and has 18 vertical ribs with large pointed tubercles. It has about 8 to 30 radial spines and 1 to 4 central spines per areole. The radial spines are whitish to brownish and up to 0.4 inches (1 cm) long. The central spines are white or yellow with a brown tip, and up to 0.8 inches (2 cm) long. Flowers are pale pink to golden yellow, up to 2 inches (5 cm) in diameter, and appear in spring.

Hardiness
USDA hardiness zones 9b to 11b: from 25 °F (−3.9 °C) to 50 °F (+10 °C).
How to Grow and Care
If you can grow cacti and succulents successfully, you can likely grow the popular Parodia without too much trouble. However, it is key to remember that Parodias don't like direct sunlight and are accustomed to more even water than many other cacti species. Therefore, the cactus mustn't be exposed to prolonged dampness and sitting water. Never let your cactus sit in a dish of water. To encourage better flowering, allow the plants to enjoy a cooling period in the winter and dramatically cut back watering. Unlike other cacti species, however, you don't need to entirely stop watering. Lastly, make sure to fertilize during the growing season for the best results.
Repot as needed, preferably during the warm season. To repot Parodia, make sure the soil is dry before repotting, then gently remove the pot. Knock away the old soil from the roots, making sure to remove any rotted or dead roots in the process. Treat any cuts with a fungicide. Place the plant in its new pot and backfill with potting soil, spreading the roots out as you repot.
See more at How to Grow and Care for Parodia.
Origin
This species is native to Argentina, Brazil, and Uruguay.
Links
- Back to genus Parodia
- Succulentopedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus