How to identify and how it grows
This is a low-branched plant a foot or two high, growing prostrate with erect branches in thick impenetrable masses ten to twenty feet across. Numerous stiff, needlelike thorns form a dense spiny yellowish coating over the entire mass. There are many pale yellow to yellow-brown flowers an inch and a half long which cluster near the tips of the stems. The fruit is globose and densely spiny, an inch or so in diameter. The plant is not attractive nor very cereus-like.
How to grow
This species can be transplanted in the spring by digging rooted stems, planting in gravelly clay soil, and irrigating sufficiently to moisten the soil in dry periods; or by digging a shallow hole and partly covering the stems with soil kept moist but not wet. The plants will grow out of doors and endure only a few degrees of frost; where the temperature drops more than fifteen degrees below freezing they must be protected outside, or grown indoors or in a warm, sunny greenhouse.
Old Man Cactus; White Persian Cat Cactus; Bunny Cactus (Cereus senilis)
(Named from the long white hairs or beards found on young plants)
How to identify and how it grows
This cactus is columnar, and some mature plants reach a height of forty-five feet. It is native to Mexico and not easily accessible. The trunk is usually unbranched, cylindrical in young plants, two or three inches in diameter, yellow-green with a scurfy waxy coating; and it is not tough. A large tree can be cut down with a small pocketknife in some instances. The twenty or twenty-five radial spines are changed over into long coarse white hairs, four to twelve inches long or even longer, and form a dense covering; hence the common and specific names, Old Man Cactus and senilis. These radials are crooked, flattened, and twisted, while the one to four central thorns are easily pulled out, all spines very fragile. In maturity a dense mass of tawny wool appears around the head of the plant. The rose-colored blossoms are two inches long, shaped like a bell or funnel, and appear only on the older cacti. They open at night and close in the early morning. The fruit is about the size of a large strawberry; it, too, is rose-colored and covered with scales and tufts of wool.
How to grow
Plants may be grown from seed in flats or pots, but the seed is rare and difficult to get. Commonly young plants are purchased and grown in pots in gravelly, sandy limestone soil. Water sufficiently to keep the soil slightly moist. A bright sunny location is best. The plants are tender to frost and thrive best in warm conservatories or greenhouses. The Old Man Cactus is a popular plant for rock gardens and is found in many homes both in this country and abroad.