Euphorbia grandicornis (Cow Horn Cactus): Care and Propagation Guide
The Euphorbia grandicornis is commonly referred to as the Cow Horn Cactus. It grows in the form of a shrub with a few stems that can grow as much as 2 meters in height. These stems also have whitish-brown spines that appear in pairs, hence earning the nickname of Cow Horn Cactus.
The spines themselves are around 3 inches long. The stems tend to develop leaves in summer but they fall off pretty quickly. Bright yellow flowers also bloom forth in the months of spring.
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Euphorbia grandicornis Care Guide
Here’s a look at the Euphorbia grandicornis (Cow Horn Cactus) care and propagation guide.
Euphorbia grandicornis needs full sun, which means they need to get direct sunlight for at least six hours on a daily basis. They might need protection from the afternoon sun depending on how strong the sun in your region is.
You can identify this by looking for burns or yellow coloring when exposed to too much sun. But typically, they grow well when planted outdoors in a sunny spot.
If you plan to grow this plant indoors, you must place it near a window that gets lots of sunlight. People who take this route like to pick south-facing windows for this reason. That way the plant will get sunlight all day long. Alternatively, invest in a good grow light for succulents that can replace natural sunlight.
Euphorbia grandicornis grows actively from spring to the fall season and that is when it should get the right amount of water. The right amount in this case is just making sure that the top two inches of soil are never dry.
So, if you spot them in that condition you should water the plant. That usually happens once a week because Euphorbia grandicornis is pretty great about tolerating drought. That is because Euphorbia grandicornis is native to regions that are described as semi-arid and rocky.
Sometimes the soil dries up to the point that it starts to feel crispy. Ideally, you should not let it get there. Your worst-case scenario should still get the plant watered once every month.
The best time to water Euphorbia grandicornis is in the morning so that they have enough ammo to deal with the sun during the day. But in the winter season, you must change tactics and water the plant only when it looks like it is starting to wilt.
Euphorbia grandicornis is a type of succulent which means they don’t need too much water. But that also means that they need well-drained soil as succulents do.
You can mix it with sand and add a little bit of perlite to the mix. If you add perlite, make sure that your potting soil and regular sand are mixed 50-50. Failing that, any commercial succulent potting mix will also get the job done.
Depending on the species, you will need to follow separate feeding techniques. But generally speaking, a little bit of fertilizing is good for Euphorbia grandicornis. You can add a little bit of organic fertilizer or compost to a young plant so that it grows healthily.
But you want to make sure that the fertilizer you are using is in liquid form and diluted a little to weaken it. You must also make sure that the fertilizer must be added to the plant in its growth period between spring and fall. In the winter, the plant is dormant and does not need to be fed as much.
If your Euphorbia grandicornis is in a container, you will have to feed it some more fertilizer compared to the ones that are being grown out in the ground. And if you notice yellow leaves developing at the bottom, that’s a sign that you need to feed the plant some fertilizer.
Euphorbia grandicornis is fairly easy to grow and maintain. That applies to the climate it is grown in too. You will need to ensure that the air is at least 50 percent humid throughout the year. If you are growing it indoors, you will be relieved to know that it grows okay in dry rooms too.
If you are looking for its best-case scenario, the temperature must be 70-80 degrees Fahrenheit during the day and 55-65 degrees Fahrenheit at night.
Pests and Diseases
Spider mites and mealybugs are the most common pest to attack these plants. And if it’s not taken care of right away, the attack turns into an infestation very quickly.
Propagating Euphorbia grandicornis
These plants can be propagated in two ways: seeds and stem cuttings.
It is difficult for the seeds to germinate quickly which is why this is the tougher
method of the two. But if you take this route, you can get commercial sand mix and
mix it in the same amount with coarse sand and plant the seeds in it. If there is
enough warmth, you will see growth in a couple of weeks. Otherwise, it can take 2-6
If you decide to use stem cuttings to propagate them, you should get a clean and
sharp knife and collect the cuttings near the plant’s branching point. This is the
easiest way to propagate the plant.