Myrtillocactus geometrizans is an incredible cactus that can bring a touch of the desert to your home or garden.

It’s relatively easy to grow it yourself, as long as you know a few little tips and tricks.

In this guide, our experts will reveal their secrets!

What is Myrtillocactus geometrizans?

Myrtillocactus geometrizans, also known as blue candle cactus or blue myrtle cactus, is a plant from the Cactaceae family, native to Central and Northern Mexico. This fast-growing cactus can make a unique indoor plant, but it can also be grown outdoors in USDA hardiness zones 9a to 11b.

Myrtillocactus geometrizans is a shrubby cactus that can grow up to 16.5 feet (5 meters) tall and just as wide. Its stems are spiky and blueish green in color, with a waxy feel and around 8 inches (20 cm) in diameter. As the plant matures, the stems take a candelabra-like look, with thick clusters growing upwards. This cactus variety also produces edible berries, which are greatly enjoyed as a snack in Mexico.

How to care for Myrtillocactus geometrizans

Let’s take a look at the care and maintenance essentials for Myrtillocactus geometrizans.

– Light requirements

The light requirements for Myrtillocactus geometrizans vary depending on the plant’s age and the time of the year. Younger plants prefer growing in partial shade or filtered sunlight. If you have a mature cactus, you can place it in direct sunlight. This plant is ideal for growing on window sills, especially if you have a room with southern or western exposure.

During winter, both young and mature Myrtillocactus geometrizans plants require less light. This cactus hibernates during the colder months. Place it in a part of the room that receives indirect sunlight until spring.

If you are growing Myrtillocactus geometrizans outdoors or in your garden, the light conditions will change accordingly with the season. As a result, it will naturally receive less light in winter, so you don’t need to worry about relocating it.

– Temperature

Myrtillocactus geometrizans is a desert plant, which means that it’s used to drastic changes in temperature throughout the day. When grown indoors, the ideal temperature range is between 70 °F and 95 °F (21 °C to 35 °C). It will need a cooler environment in winter, with temperatures averaging around 55 °F (13 °C).

Myrtillocactus geometrizans can tolerate temperatures as low as 25 °F (-4 °C). However, it’s best to avoid exposing it to freezing temperatures for extended periods, which can permanently damage the plant. When growing this cactus outdoors, ensure that winter temperatures do not drop below 50 °F (10 °C).

– Water requirements

Myrtillocactus geometrizans is a type of desert cactus, which requires little watering. During the summer months, you can water them once every two weeks and allow the soil to dry before watering again. In winter, you can water it as rarely as once a month. The cactus enters a period of dormancy, and as a result, it will need even less water than usual.

Since it has a shallow root system, over-watering Myrtillocactus geometrizans can cause many problems. Ideally, you should allow the soil to dry out in between waterings completely. This plant can tolerate drought, so it will be very forgiving if you forget to water it for a few days. You can use your finger to test whether it needs to be watered. For more accurate results, we highly recommend using a moisture meter.

Keeping a strict watering schedule is crucial for Myrtillocactus geometrizans. What’s more important is making sure that the soil is well-draining. Check our guide for the best soil mix below.

– Humidity

Myrtillocactus geometrizans can be highly sensitive to humidity, which can cause wilting and fungal problems. Ideally, the figure you should aim for is around 30 percent, which is lower than the humidity level in most homes.

If you are growing tropical plants in your home, you should grow this cactus in a separate room. Also, it might be worth investing in a dehumidifier if the moisture levels in your home are above 60 percent.

– Fertilizers

The Myrtillocactus geometrizans cactus is not a heavy feeder. It has very little need for fertilizers. You can use a diluted fertilizer solution to boost its growth during spring and summer but cut back on feeding while the plant is hibernating. Monthly applications of a fertilizer with a nutrient ratio of 5-10-5 are ideal.

When growing cactus plants such as Myrtillocactus geometrizans, it’s often better to under-feed rather than give them too much fertilizer. In their native habitat, these plants manage to grow in very harsh conditions and inferior soils. Their roots are not used to high levels of nutrients, which can cause fertilizer burn.

– Best soil

Like all cactus plants, Myrtillocactus geometrizans prefer growing in sandy soils that are also porous, well-draining, and slightly acidic, with a pH ranging from 5 to 6.5. The main thing to aim for is excellent drainage, as cacti are particularly sensitive to stagnant water in the soil.

You can use cactus mix for potting your Myrtillocactus geometrizans. One thing that’s worth keeping in mind, though, is that even cactus soil mixes that are commercially available are still fairly water retentive. We recommend amending these soils with a bit of perlite to improve drainage and soil aeration further. You can mix two parts of cactus soil with one part perlite or even pumice for the best results.

Alternatively, you can also make your Myrtillocactus geometrizans soil mix at home.

Here are two ‘recipes’ we suggest trying:

  • For indoor growth: mix equal parts bark and peat moss to create the base. Combine equal parts of this base with coarse sand and perlite or other perlite substitutes such as vermiculite or pumice.
  • For outdoor growth: create a soil base by mixing equal parts bark and peat moss. Then, combine one part soil base with equal parts coarse sand and insoluble grit. You can also add a bit of gravel to the mix to further improve drainage. Cactus plants grown in the garden need more soil than indoor plants, which is why using amendments such as perlite or pumice can quickly turn into a very costly affair.

If you can, avoid using compost as a base for your Myrtillocactus geometrizans. Cactus plants grow best in poor soils without too many nutrients. Compost is very rich in nutrients, and as a result, it can burn the roots of the cactus plants.

– When to repot

Myrtillocactus geometrizans’ growth rate is fairly rapid and can reach heights of over 3 feet (90 cm) in just a few years. On average, it can grow as tall as 16.5 feet (5 meters), especially when grown outdoors. Luckily, it has a shallow root system, so you will only need to repot it once every two years.

The ideal container for Myrtillocactus geometrizans should be made out of clay. As this cactus grows, it can become very top-heavy, so it needs a pot supporting the weight. Ceramic and terracotta are heavier than plastic, making them an excellent choice. They also allow the water to evaporate from the soil faster than plastic and aid with soil aeration.

– Does it produce flowers?

Yes! Once your Myrtillocactus geometrizans reach at least 2 feet (60 cm) in height, you can expect it to bloom. The cactus will produce small, pale yellow flowers that grow in rows along the plant’s stem. It also produces small, edible fruits which look similar to blueberries.

The fruit of the Myrtillocactus geometrizans is called bilberry, which also gives this cactus one of its common names, ‘the bilberry cactus.’ These small berries have a sweet, pleasant taste and can either be eaten fresh or dried the same way as cranberries or raisins. They are extremely popular in Mexico, where they are harvested from the wild and sold in markets.

– Is it safe for pets?

Myrtillocactus geometrizans is not toxic to cats and dogs. However, it’s best to keep it out of their reach, as the thorns of this cactus can cause injuries to the throat and mouth.

It’s also best that Myrtillocactus geometrizans contain small amounts of mescaline. It’s a psychoactive substance found in other cactus species. This substance can have a hallucinogenic effect if ingested. As a result, make sure that you keep this plant away from pets and children.

How to propagate Myrtillocactus geometrizans

The easiest way to propagate Myrtillocactus geometrizans is through stem cuttings. Wait until your cactus has started producing side stems and propagate it in either spring or summer.

Here’s a step-by-step guide on propagating Myrtillocactus geometrizans through stem cuttings:

  1. Use a sharp, clean knife and cut a 4 inch (10 cm) long stem.
  2. Keep the stem in a dry, bright room for at least three weeks. During this time, the stem’s bottom should dry out and produce a hard, light brown callus.
  3. Do not water your stem while you’re waiting for the callus to form. It has enough moisture reserves to survive this short period of drought.
  4. After the callus has formed, you can move the cutting into the soil. Pick a container that’s about 6 inches (15 cm) wide.
  5. You will need to provide a very well-draining substrate for your cutting to prevent any rot at the stem’s bottom. The ideal mix should be equal parts sand, pumice (or perlite), and compost.
  6. Use your finger to dig out a hole that reaches about halfway down the container. Put the cutting inside, and pile the surrounding soil to keep it upright.
  7. Use a spray pump to water the soil gently. You can also use a rooting hormone at this stage to give the cutting a boost.
  8. The propagated stem should produce roots in a couple of weeks.

If you have a mature Myrtillocactus geometrizans cactus producing fruit, you can also propagate it through seeds. Wait until the berries are fully ripe, then remove the seeds.

Allow them to dry for at least a week. Then, plant the seeds in a clay container with a well-draining potting mix. Use a spray pump to keep the soil moist, and keep the container on a bright window sill. Myrtillocactus geometrizans is a fast-growing plant, so the seeds should take 2 to 3 weeks to germinate.

Myrtillocactus geometrizans common problems

The most common problem that Myrtillocactus geometrizans encounters is overwatering. This can cause the cactus to become soft and wilted, with yellow and brown spots. Make sure to keep watering down to a minimum during winter, and only water it in summer when the soil feels dry to the touch.

Myrtillocactus geometrizans is also sensitive to too little light, especially during its growth period. During spring and summer, make sure that it receives at least 8 hours of direct sunlight.

Mature Myrtillocactus geometrizans can suffer from being root-bound. This fast-growing cactus develops an extensive root system as it grows and should be repotted once every two years.

On the positive side, Myrtillocactus geometrizans are very resistant to pests and diseases. As long as you provide it with enough light and space to grow and you don’t overdo the watering, this sturdy cactus will thrive for many years to come.

Conclusion

If you’re looking for an incredible cactus to grow at home, Myrtillocactus geometrizans is a top choice. With this guide, you’ll have no problems keeping it for many years.

So, let’s go over some of the basics;

  • As a desert plant, Myrtillocactus geometrizans doesn’t need a lot of water;
  • It also enjoys well-draining, slightly acidic soils, and it’s worth combining cactus soil with perlite for the best results;
  • During winter, it becomes dormant and can handle lower temperatures and periods of drought;
  • Low humidity levels are essential. It’s best if you grow Myrtillocactus geometrizans in a separate room from your tropical plants.

Follow these tips, and your Myrtillocactus geometrizans will thrive!

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