Echinopsis chamaecereus f. lutea
Yellow peanut cactus

A cactus curiosity, this is grown for its banana-like stems because its red flowers rarely appear. It has no chlorophyll so must be grafted on to a green cactus that can supply it with food. The slender elongated stem slowly forms a small clump. Grown only as a pot plant, it needs some care; shade its tender body from summer sun to avoid scorch marks. The grafting stock determines the minimum temperature.

H 13 cm (5 in), S 25 cm (10 in). Av. min.10°C (50°F).

Echinopsis mamillosa f. kermesina

When only 8 cm (3 in) diameter, this small cactus produces flowers that open on summer nights and last for about 24 hours. Protect the plant from cold to avoid unsightly scarring and grow it in full sun.

H 30 cm (12 in), S 23 cm (9 in). Min. 7°C (45°F).

Echinopsis densispina

Often labelled with its old name of Labivia famatimensis, this cactus flowers when 2.5-5 cm (1-2 in) tall. In spring or summer, it bears a profusion of fairly large, funnel-shaped flowers with the dasiy-like petals that are typical of Labivia; they range from white; yellow and orange to pink, purple or red. The pale spines are bristly. This species prefers light shade or, when in bloom, sun.

H and S 60 cm (2 ft). Min 5°C (41°F).

Echinopsis oxygona

Widely grown for a century because it is robust and easily propagated, this cactus is a fine flowering plant. The long-necked blooms, some scented, are white to lavender in hue and about 13 cm (5 in) across. They appear intermittently in spring and summer, and open at night for up to 24 hours. The globular body is usually dark  green  and the spines range  from black to white in colour.

H 30 cm (12 in), S 1.2 m (4 ft). Min 5° (41°F).

Echinopsis chamaecereus

This small slender plant has very short white spines, and branches rapidly to form a cluster of creeping candle-like stems. It flowers prolifically, producing funnel-shaped blooms, which open fully only in sun, all along the stem in late spring or early summer. The small berries are spiny. This cactus tolerates neglect and prefers slight shade; it is easily grown from offsets.

H 15cm (6 in), S unlimited. Min. 0°C (32°F).