Actual size and flowering may vary slightly based on season.
Big Horn Euphorbia
Big Horn Euphorbia has lime-green, three- to four-winged stems that twist and pinch into zig-zag segments, edged with long paired spines like cow horns. It grows into a shrub about 5 to 6 feet tall and wide, and it grows fairly fast. It makes a bold accent in a large patio pot or a warm, sheltered bed.
Best for: large pots and sheltered accent spots with frost protection, well away from paths, kids and pets.
Its winged stems pinch into twisted, zig-zag segments with long paired spines. It grows about 5 to 6 feet tall and wide.
In a large pot it can be moved under cover on freeze nights. Use fast-draining mix and never let water stand at the roots.
Plant it in the ground only in a warm, sheltered spot where you can cover it in cold snaps.
It is not frost hardy, rots if water stands at the roots, and its long spines and sap make it a poor fit near paths and pets.
Water deeply, then let the soil dry out before the next watering. Water regularly in the warm months when the soil is dry, and keep it nearly dry in winter. Soggy soil rots the roots.
It prefers full sun but takes some shade. Move a shaded plant into full sun slowly, over a few weeks, to avoid scorching.
It is frost sensitive, about 30 to 32°F. Cover it on freeze nights or move a pot under cover.
Every cut or broken stem bleeds milky sap that irritates skin and eyes. Wear gloves, long sleeves and eye protection when you plant or trim it. The long spines and sap both call for thick gloves.
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 big horn or cow horn?
Its stems carry long paired spines, up to about 3 inches, that look like cow horns along the winged edges.
How big does it get?
It grows into a shrub about 5 to 6 feet tall and wide.
How fast does it grow?
It is a fairly fast grower for a succulent, and in the ground it can fill out in a season or two. Give it room to reach about 6 feet across.
How cold can it take?
It is frost sensitive, about 30 to 32°F. Cover it or move a pot under cover on freeze nights.
How often should I water it?
Water in the warm months when the soil is dry and keep it nearly dry in winter. Never let water stand at the roots.
Does it need full sun?
It prefers full sun but takes some shade. Move a shaded plant into full sun slowly to prevent scorching.
Is the sap dangerous?
Yes, handle it with care. The milky sap from a cut or broken stem irritates skin and eyes and is toxic if eaten. Wear gloves and eye protection, and wash sap off skin with water.
Is it toxic to pets?
Yes. Euphorbias are toxic to dogs and cats if chewed; the sap irritates the mouth and stomach and can cause vomiting. Plant it where pets cannot chew it.
Is big horn euphorbia a cactus?
No. It is a euphorbia, a succulent related to poinsettias, even though it looks like a cactus. A broken stem bleeds milky sap, which cacti do not.
Big Horn Euphorbia for sale in Arizona, delivered to you
Big Horn Euphorbia is Euphorbia grandicornis, also called cow horn, a southeast African succulent with twisting winged stems and long paired spines. Below is what to expect: size, sun, water, frost and handling.
Sourced from trusted Arizona growers and delivered directly to your door, job site, or property. We deliver across the Valley and to nearby towns, and quote delivery anywhere else in Arizona.
What is big horn euphorbia?
It is Euphorbia grandicornis, a southeast African succulent with twisting winged stems and long paired spines.
How big does Euphorbia grandicornis get?
Plan for about 5 to 6 feet tall and wide.
Is cow horn euphorbia frost hardy?
No. It is frost sensitive, about 30 to 32°F. Protect it on freeze nights.
How to water cow horn euphorbia in Phoenix
Water in the warm months when dry, and keep it nearly dry in winter.
Cow horn euphorbia sun
It prefers full sun and takes some shade. Move shaded plants into sun slowly.
Is Euphorbia grandicornis toxic?
Yes. The sap irritates skin, eyes and mouth. Wear gloves and keep it away from pets.
We deliver across the Valley, from Phoenix, Scottsdale and Mesa out to San Tan Valley, Maricopa and Casa Grande, and up to Prescott, Sedona, Payson and Globe. See delivery areas and rates.