Actual size and flowering may vary slightly based on season.
Gymnocalycium saglionis
Gymnocalycium saglionis, the giant chin cactus, is a round, blue-green barrel from northwest Argentina with thick, curved spines. It stays a single head and grows slowly to about a foot across, and very old plants can reach 3 feet tall. Pinkish white flowers open near the top again and again through the warm season, followed by round red fruit. It suits pots, cactus beds and rock gardens.
Best for: pots, cactus beds and rock gardens where a round, single barrel fits. It grows slowly and blooms off and on through the warm season.
It stays a single round head about a foot across for many years. That shape makes a strong focal point in a wide pot.
It grows slowly, so it keeps its size in a bed for years. Very old plants can reach 3 feet tall and about 16 inches across.
Pinkish white flowers open near the top several times through the warm season. Round red fruit follows the flowers.
It can be damaged below about 20°F, so cover it on frost nights. Wet winter soil can rot it. Shade it from the hottest summer sun.
Wait about a week after planting before the first water. Then water about every other week while nights stay above 60°F. Once it is rooted, give it a little water when the soil is dry in the warm months. Keep it dry in winter unless the winter is very dry.
It takes full sun to part shade. In the Valley, shade it from the hottest summer sun so it does not scorch.
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 on cold nights.
Use a pot with a drainage hole and a gritty cactus mix with plenty of pumice, perlite or coarse sand. Water it when the mix is dry, and keep it drier in winter.
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.
How big does Gymnocalycium saglionis get?
It grows slowly to about 12 to 16 inches across. Very old plants can reach about 3 feet tall, but it takes many years.
Why is it called giant chin cactus?
Gymnocalycium are called chin cactus for the chin-like bump under each spine cluster. This is one of the largest kinds in the group.
When does it bloom?
It blooms several times through the warm season with pinkish white flowers near the top. Round red fruit follows, and you can leave it on the plant.
Does it need shade in Phoenix?
It takes full sun to part shade. In the Valley, shade it from the hottest summer sun so it does not scorch.
How often should I water it?
Wait about a week after planting, then water about every other week while nights stay above 60°F. Once it is rooted, give it a little water when the soil is dry in the warm months. Keep it dry in winter.
How cold can it take?
It can be damaged below about 20°F. On frost nights, cover it with frost cloth or a sheet down to the ground, and move pots under a patio roof.
What soil does it need in the Valley?
Plant it in soil that drains fast, like sandy or gravelly native soil, with no compost. If you hit caliche, break through it so water drains, or choose another spot.
How do I handle it without getting stuck?
Wear thick leather gloves, and wrap the plant in folded newspaper or cloth to lift it. Keep it away from spots where kids play.
Gymnocalycium saglionis for sale in Arizona, delivered to you
Gymnocalycium saglionis, the giant chin cactus, is a slow, round barrel from northwest Argentina. Below is what to expect in a Valley pot or bed: size, sun, water, cold, flowers and fruit.
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What is a giant chin cactus?
It is Gymnocalycium saglionis, a round, blue-green barrel cactus from northwest Argentina. It has thick, curved spines.
How big does Gymnocalycium saglionis get?
It grows slowly to about 12 to 16 inches across. Very old plants can reach about 3 feet tall.
Gymnocalycium saglionis flowers and fruit
Pinkish white flowers open near the top several times through the warm season, followed by round red fruit.
Growing Gymnocalycium saglionis in Phoenix
Plant it in fast-draining soil in full sun to part shade, with shade from the hottest summer sun. Keep it dry in winter.
Is giant chin cactus cold hardy?
It can be damaged below about 20°F. Cover it with frost cloth on frost nights, and keep the soil dry through winter.
Gymnocalycium saglionis in a pot
It makes a good focal pot plant. Use a gritty cactus mix and a wide pot with a drainage hole.
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