A unique aspect of barrels is that the areoles are found on vertical ridges. Curved spines are very numerous and vary in color from red to yellow.
They can be found on south-facing rocky slopes and canyon walls from 2000 to 4000 feet (600- 1200 m). They are commonly 1 to 3 feet (30-92 cm) tall but in the right conditions can attain 5 feet (1.5 m) or more and reach an age of 40 or 50 years.
The yellow flowers form a ring on the head. The flowering period is March through May. Barrels lean to the south (toward the sun) as they age.