Actual size and flowering may vary slightly based on season.
Goats Horn Cactus
Goats Horn Cactus is a ribbed star cactus from northern Mexico, flecked with white and wrapped in long, curling spines that give it its name. It blooms young, often at only a few inches tall, with large, sweet-smelling yellow flowers that have a red center. It starts as a ball and slowly grows into a short column. It suits pots, rock gardens and patio beds.
Best for: patio pots, rock gardens and small cactus beds where its curling spines and big yellow flowers can be seen up close.
It can flower when only about 2 inches tall, so even a small pot plant can bloom. Use a gritty cactus mix and a pot with a drainage hole.
The long, flattened spines curl around the white-flecked ribs like goat horns. Set it among rocks near a path or seat where the texture shows, but not where people brush past.
Large yellow flowers with a red center open in summer and have a sweet scent. Round, scaly fruit can follow.
Wet soil, most of all in fall and winter, rots it quickly. Frost below about 20°F can damage it, so cover it or move a pot under a roof on the coldest nights.
- Plant to plant12 in apart
Wait about a week after planting before the first water. In a pot, water about weekly in hot weather; in the ground, about every other week while nights stay above 60°F. Keep it dry from fall through winter.
It grows in full sun to all-day light shade. In the Valley, give it light shade through the summer afternoon.
It can be damaged below about 20°F. On frost nights, cover it with frost cloth or a sheet that reaches the ground, not plastic, and take it off in the morning. Move pots under a patio roof.
Feed a potted plant with a weak liquid fertilizer about monthly from April through September. Plants in the ground do not need it.
Drainage test first. Dig the hole and fill it with water. If water is still sitting in the hole a day later, you likely hit caliche, clay or hard soil, so fix the drainage before planting. If it drains very fast, the soil is sandy. Standing water around roots is a common reason new plants fail.
Weed cloth. Cut it away from the planting hole and where the roots will spread. Remove any plastic sheeting completely, since it keeps water and air out of the soil.
Rock or decomposed granite with no soil underneath. Bring in soil close in texture to your native soil, mix it with the soil below, and build up enough depth for roots before planting.
If you can break through. Use a breaker bar, pick, or jackhammer. Dig through the caliche and break out the solid chunks. Backfill with the soil you dug out, with no compost or manure in the hole. Confirm drainage before planting.
If you cannot break through. Dig narrow holes through the hard layer beside the root ball, not under it, and refill them with the same soil, not gravel. If it still will not drain, plant on a low mound of the same soil.
Root ball. Check the outside edges for any roots circling around. Loosen or cut those so they grow outward. Do not break up the center of the root ball.
Depth. The top of the root ball should sit at or just slightly above the surrounding soil level. Planting too deep can lead to rot and kill the plant.
Drip emitters. At planting, put the emitters on the root ball, on different sides of the plant. After about 2 months, move them to the outer edge of the root ball. Over the first year, add emitters farther out toward the edge of the branches as roots grow. Once a plant is rooted, never water only at the trunk.
Why is it called goats horn cactus?
Its long, flattened spines curl and twist around the plant like goat horns. The ribs are also dotted with small white flecks.
How big does it get?
It grows slowly, from a ball into a short column about 4 to 6 inches wide. Old plants can reach 16 inches or more, and in time up to about 4 feet.
When does it bloom?
In summer, with large yellow flowers that have a red center and a sweet scent. It can start blooming when only a few inches tall.
Does it need full sun in Phoenix?
It grows in full sun to all-day light shade. In the Valley, light shade through the summer afternoon keeps it from scorching.
How often should I water it?
In a pot, water about weekly in hot weather and let the mix dry out between drinks. In the ground, water about every other week in summer once rooted, and keep it dry from fall through winter.
How cold can it take?
It is usually rated to about 20°F, and some growers report a little colder. On frost nights, cover it with frost cloth down to the ground, and move pots under a patio roof.
Should I fertilize it?
In a pot, feed it with a weak liquid fertilizer about once a month from April through September. In the ground it does not need feeding.
How do I handle it?
Wear thick gloves, and wrap the plant in folded newspaper to lift it. The spines are stiff and can poke through thin gloves.
Goats Horn Cactus for sale in Arizona, delivered to you
Goats Horn Cactus (Astrophytum capricorne) is a star cactus named for its long, curling spines. This page covers its size, flowers, sun, water, cold and how to grow it in a pot or bed in the Valley.
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What is a goats horn cactus?
It is Astrophytum capricorne, a star cactus from northern Mexico with white-flecked ribs and long, curling spines.
How big does goats horn cactus get?
It grows slowly from a ball into a short column 4 to 6 inches wide. Old plants can pass 16 inches tall.
Goats horn cactus flowers
Large yellow flowers with a red center open in summer, and they are sweetly scented. Plants can bloom at a few inches tall.
Watering goats horn cactus in Phoenix
Water a potted plant about weekly in hot weather and let it dry between drinks. Keep it dry from fall through winter to prevent rot.
Is goats horn cactus cold hardy?
It is usually rated to about 20°F. Cover it with frost cloth on frost nights, or move a pot under cover.
Goats horn cactus in a pot
It suits a pot or a rock garden. Use a gritty cactus mix, and feed a potted plant lightly each month from spring through summer.
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