Bunny ears cactus

Identification and origin

Opuntia microdasys is a cactus in the family Cactaceae, native to central and northern Mexico, from the Gulf of Mexico region to the northwest and southwest of the country. It has become naturalized in many warm regions, notably around the Mediterranean, in South Africa and in Australia. Its species name comes from Greek and means “very small, shaggy hairs.”

It is a bushy, heavily branched plant that forms low clumps, ranging from creeping to nearly upright. Growth is slow. It usually reaches 20 in – 3.5 ft tall and, planted in the ground in a mild climate, can spread 4–5 ft. The stems are flat, fleshy pads, oval to round, light to medium green and finely fuzzy, up to 6 in long. New pads often appear in pairs at the tips of older ones, which is where the bunny-ear resemblance comes from.

This cactus has no true spines. Its closely spaced areoles carry white, yellow or reddish-brown glochids: fine, barbed, cottony-looking bristles that detach at the slightest brush and lodge in the skin.

In spring and summer, plants grown outdoors bear pale yellow, bowl-shaped flowers 2–2 in across, with a dense ring of stamens in the center. They are followed by round, juicy fruits about 1 in across, red to purple and covered in glochids. Indoors, it rarely blooms.

Light

Give it the sunniest spot you have: at least six hours of direct sun a day, in a south- or west-facing window. It tolerates partial shade, but too little light produces soft, stretched, misshapen pads. Turn the pot regularly so every side gets light; otherwise the plant becomes lopsided as it leans toward the glass. Full sun also encourages flower buds. In summer it can spend the season outdoors in full sun after gradual acclimation.

Watering

Overwatering is the leading cause of failure. During the growing season, from spring to early fall, wait until the mix has dried, at least in the top 1 in and ideally all the way through, then water thoroughly. Bottom-watering works well: set the pot in a basin of water for about ten minutes, check that the mix is moist, then let it drain. Never leave water standing in the saucer. Use tepid rainwater if you can, as minerals in tap water leave white deposits.

In winter, during the rest period, water hardly at all: just enough, in the morning, to keep the pads from shriveling. Shriveled pads signal real thirst; stalled growth, blisters or a softening base point instead to too much water. It likes dry air and needs no extra humidity.

Potting mix

It needs a very fast-draining mix. A cactus potting mix works, as long as you avoid heavily peat-based blends that stay wet too long. You can also combine three parts fine grit or coarse sand, one part potting soil and one part coir or shredded bark: a good cactus mix lets water through in under a minute. The pot must have a drainage hole. A thin layer of grit can top the surface.

During the growing season, feed three or four times with a liquid cactus fertilizer or a high-potassium fertilizer such as a tomato feed, which encourages flowering. Avoid high-nitrogen fertilizers, which produce soft tissue. Stop feeding entirely during the winter rest.

Temperature

During the growing season it is comfortable between 55 °F and 75 °F, with nights cooler than days. In winter, a cool rest between 50 °F and 64 °F, in a bright room away from radiators, encourages flowering. Do not let it drop below 39 °F; it cannot take frost, and excessive cold causes discolored patches and dieback of the pads. Outdoors it is grown in USDA zones 9a to 11b; elsewhere, bring it inside before the first frost.

Repotting

In early spring, slide the plant out of its pot to see whether the roots fill the space. If they do, move it to a pot just one size larger: an oversized pot holds too much moisture and invites rot. To handle the plant without touching the glochids, wrap it in a strip of newspaper folded several times, or wear thick gloves.

Pruning

No pruning is needed. You can, however, remove a damaged or stretched pad in spring or summer and use it as a cutting.

Propagation

Pad cuttings are the easiest method. In spring or summer, detach a pad while holding it with folded newspaper. Let the cut dry and callus for a day to a week, then set the base on a mix of two parts potting soil and one part grit, barely pressing it in. Keep the mix just slightly moist, in good light but out of scorching sun: excess water would rot the cutting before it roots.

Sow seed in spring: soak the seeds, sow them on a sandy mix, cover with glass or a clear bag and keep them at about 70 °F in bright, indirect light. Seedlings can take up to a year to grow large enough to pot on.

Cultivated forms include ‘Albata’, with short white glochids and pale yellow flowers; the crested form ‘Funny Bunny’, with twisted pads and golden yellow glochids; and ‘Caress’, which is barely prickly. Dyed plants are also sold as novelties.

Common problems

• Rot at the base or roots: watering too often, poor drainage or an oversized pot.
• Shriveled pads: prolonged lack of water during the growing season.
• Soft, stretched pads: not enough light.
• No flowers: plant too young, insufficient light or no cool, dry winter rest.
• Corky brown patches: too much humidity or brightness; correct conditions gradually.
• Pests: mealybugs, scale insects and spider mites.
• Skin irritation: glochids lodged in the skin during handling.

The same symptom can have several causes: always consider watering, light, temperature and the condition of the roots before drawing conclusions.

Toxicity

The plant is not toxic if eaten by dogs, cats or horses, and its fruit, once cleaned of glochids, is even edible. The hazard is mechanical: its barbed glochids irritate the skin and eyes of people and dogs alike. Wear gloves when handling it, keep it out of reach of children and curious pets and, if glochids get into an eye or an animal’s mouth, contact a doctor or veterinarian.