Isolatocereus dumortieri: Care and Propagation Guide

The plant Isolatocereus dumortieri comes from the Isolatocereus genus but now it’s also a part of the Stenocereus genus. There are 20 cacti species in the second category and they are from central Mexico, southwest US, Venezuela, Colombia and Central America.

This particular plant is also called Candelabra cactus, which is a blue-green columnar. It grows about 6 to 15 meters in height and the blooms at the top are green-white in color. It also produces fruits that are red in color and edible.

isolatocereus dumortieri

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How to Care for Isolatocereus Dumortieri

Isolatocereus dumortieri plants are also referred to as the candlelight cactus and the flowers bloom at night. They will stay that way till noon at the top of the tree. The stems of this plant are green-blue in color and grow up to 11.8 inches.

They have about 5 to 8 mildly spiral and vertical ribs with areolas with white or yellow thorns. The plant also has plugs that are 0.39 to 1.9 inches long. And here’s how you care for this plant.


Isolatocereus dumortieri plants need full sun, but they do tend to burn if the summer sunlight is harsh. A grown Isolatocereus dumortieri should be above 32 degrees Fahrenheit. If it drops below that you will see spots on the plant’s epidermis. But it can handle being at 24 degrees Fahrenheit for a short period of time.


In the summer, the Isolatocereus dumortieri plant needs to be watered regularly. Just make sure that the pot has a good draining mechanism. When it’s hot outside, these plants do appreciate a good deal of water. That’s the rule for summer and spring. You check the soil for dryness and water the plant.

You need to do this once every 7 days in summer and once every 15 days in spring.

When you enter September, you should start bringing down the amount of water you give the plant. That will help it move into its semi-dormant stage. In October, you will need to change the watering timetable to a winter schedule.

In the fall, you should bring the amount of water way down and in winter, don’t water the plant at all. Overwatering is a real problem with Isolatocereus dumortieri plants because the tissues and roots tend to rot.

isolatocereus dumortieri


This plant grows best in well-drained soil along with a little bit of organic matter. You should get commercial cactus substrate and mix 75 percent of it with garden soil being the rest.


You will need to fertilize this plant once in the middle of spring and once in early summer. It needs to be mineral fertilizer and specific to Cactaceae.

You can also do it two to three times in both seasons if need be.


Isolatocereus dumortieri plants can grow outside in the summer when the temperature is above 86 degrees Fahrenheit. That’s good for the plant if you live in a hot and dry climate. But it will need to be in soil that drains well. Make sure it is totally dry in the winter and you can keep them out if it’s not too cold. That’s if the temperature does not fall under 35 degrees Fahrenheit.

Pests and Diseases

As mentioned earlier, this plant does not do very well when the soil doesn’t drain well. The roots will start to rot and that will attract plenty of insects that like to feed on this plant.


Isolatocereus dumortieri plants grow about 9 to 12 meters tall. Sometimes, they might grow above 12 meters and that shouldn’t be a problem if you’re growing them outside. So, typically, they don’t need any pruning.

isolatocereus dumortieri

Potting and Repotting

This depends on the growth of the plant. But it is recommended that you repot Isolatocereus dumortieri plants once every two to three years. But by that time, you will be dealing with grown plants. And since they have thorns, you should be careful not to hurt your hands.

Propagating Isolatocereus Dumortieri

The Isolatocereus dumortieri plants can be propagated using seeds or cuttings from the branches in the spring. You can either pick the softwood cuttings or the woody cuttings from the stem.

But the plant cuttings will form calluses after cutting. So, you should wait for them to heal before you plant them back in the soil.

Luckily, it’s quite easy to grow this plant. The original plant has six or seven ribs with areoles that are closely spaced. Each of them will have 1 to 4 central spines that in turn have 9 to 11 radial spines.

They are propagated in rocky areas in small groups that are spaced well apart from each other. You can also grow them in small pots and keep them as such while they are still young.

Isolatocereus dumortieri plants are well-suited to be grown in Mediterranean coastal gardens precisely for this reason.