Myrtillocactus geometrizans (also known as the bilberry cacti, blueberry cactus, whortleberry cactus, blue candle, Cereus geometrizans, Cereus pugioniferus, Myrtillocereus geometrizans, Myrtillocactus grandiareolatus or pitaya / pitahaya / dragon fruit) is a type of cactus that grows naturally in central and northern Mexico.
Myrtillocactus geometrizans grows tree-like with candelabra-like branched shoots, reaches growth heights of up to 4 meters and forms a distinct trunk. The blue-green shoots are tapered at the base and have diameters of up to 10 centimeters. There are 5 to 6 straight, rounded ribs. The single, black, dagger-like central spine, broad at the base, is 1 to 7 centimeters long. The 5 to 9 marginal spines are brownish to blackish and 2 to 10 millimeters long.
This species is characteristic of xerophytic scrub and transition areas with low deciduous forest. This species is characteristic of the arid and semi-arid zones of the center of the country, and is also found in the dry deciduous forest. It is generally found in gypsum and limestone soils, often with high salt content, as is the case in the Tehuacán-Cuicatlán valley. The sites where the species is distributed have an arid, semi-warm, dry climate, with a marked rainy season in the summer, where the average annual rainfall is between 380 and 450 mm and its average temperature throughout the year is 21 °C.
|Planting location:||Full sun, bright direct sunlight|
|Height:||When mature 4-5 m|
|Soil:||Light nutritious, well-drained soil. Recommended to grow in special ready-made soil for cacti and succulents|
|Temperature:||25-35 °C, in winter 10-12 °C|
|Flowering time: ||From March to June|
|Difficult to care for:||Medium|
|Air humidity:||From 55%|
|Fertilizer frequency:||Medium. Fertilizer only during active growth (at least during resting period)|
|Water use:||Low water use. Moderate watering only when the top layer of substrate dries out|
|Recommended for cultivation:||In rooms - on the sunniest windows / in greenhouses / sometimes used as a reliable rootstock for particularly valuable cacti|
|Composition of the soil mixture:||A mixture consisting of clayey soil and coarse sand, acidity (pH): slightly acidic (5.0-6.0)|
|Transplanting:||As it grows, in spring. Should be transplanted approximately every 2 years|
|Propagation:||By seeds and cuttings|
This species is endemic to Mexico. In the Zapotitlán region it is an abundant plant in plains, where it forms large colonies. In Mexico it is distributed in the following states: Aguascalientes, Baja California, Sonora, Durango, Guanajuato, Guerrero, Hidalgo, Jalisco, State of Mexico, Michoacan, Morelos, Nuevo Leon, Oaxaca, Puebla, Queretaro, San Luis Potosi, Tamaulipas, Tlaxcala, Veracruz, Zacatecas. Cultivated in Mexico and Central America.456
Spanish trivial names are “Garambullo” and “Padre Nuestro”, and in German it is known as “Heidelbeerkaktus”.
A fast-growing species. Excellent as a rootstock for grafting less vigorous (e.g. chlorophyll-deficient) cactus species and varieties. Very sensitive to frost. It comes into production around the age of 15. The flowers are white and about 2–2.5 cm across. The fruit is a dark purple berry that can be eaten. It looks like a Vaccinium myrtillus (bilberry or whortleberry) fruit on the outside, which is where the scientific name and the English name come from.
The first description as Cereus geometrizans was published in 1837 by Ludwig Georg Karl Pfeiffer. Michelangelo Console placed it in the genus Myrtillocactus in 1897.
In the IUCN Red List of Threatened Species, the species is listed as Least Concern (LC), i.e., not endangered.
Young plants of blueberry cactus propagated by seed are almost completely thornless during the first years. They are often used as rootstocks because they grow quickly and are easy to handle. The only stumbling block is that, regardless of what you graft onto it, it requires a minimum temperature of 10°C or higher in winter.
Myrtillocactus are as easy to grow as any Cereus or Echinopsis. They can cope with any acceptable soil and require plenty of water from spring to autumn.
In winter they require slightly different treatment. They are easily spotted if the temperature gets too low. The risk of such stains is especially high at high humidity.
If they are grown in living quarters where the temperature never drops below 16°C, they must be watered from time to time, even during the winter, to prevent them from shrivelling up. To maintain the beautiful blue color of the plant body, they need as much light as possible.
The bilberry cactus grows quickly, which is why it is often used as a base plant for grafting. It can grow up to 15 feet tall if the conditions are right.
The flowers often come in clusters from the areoles on the upper part of the stems. In large plants the flowers are quite small, rarely more than 2.5 centimetres long. They are funnel-shaped and open completely during the night and are very fragrant. The flowers are white to white-pink. The fruits are small, almost spherical and bluish-purple when ripe. The fruit is edible and is considered tasty.
When it is about 60 cm tall, it starts to bloom. It blooms between March and June, and each flower only lasts for one day.
Fruit, dark red, purple or bluish at maturity, globose, 8-15 mm in diameter, sometimes with some faint spines.2 Flesh Juicy purple flesh. Seed asymmetrical, oval, 1.2 to 1.7 mm long by 1 to 1.5 mm wide, black, rough in appearance. Taste is similar to that of a prickly pear.
- Myrtillocactus cochal – a strongly branching cactus with long needles, 3-6 in each areola, one long one in the center and several smaller ones around it;
- Myrtillocactus geometricus – an erect, column-like, bluish-gray, cactus with small needles up to 1-2mm;
- Myrtillocactus eichlamii is the only species of myrtillocactus that occurs not only in Mexico but also in Guatemala;
- Myrtillocactus schenckei – this species differs from the other myrtillocacti in having larger, closely spaced areoles with black felted pubescence;
- Myrtillocactus crested (Myrtillocactus geometrizans forma cristata) is a hybrid of Myrtillocactus that forms a tree-like trunk that tends to branch out and cluster into one another. Sometimes when new branches form from the crest, they can revert to a normal growth pattern, resulting in a more bizarre appearance;
- Myrtillocactus geometrizans cv. Fukurokuryuzinboku is a hybrid of Myrtillocactus, also known as Breast Cactus, so named for its resemblance of areoles to female breasts. It is a grayish blue erect cactus up to 3 -10 cm thick. It has 5-8 odd chin ribs shaped like female breasts, which are about 2.5 cm deep, and areoles 3-5 cm apart. Each rib is bordered by irregularly protruding longitudinal grooves.
How to take care of it?
If you want to have a specimen, we recommend the following care:
The garambullo is a sun-loving plant. It lives in the arid and semi-arid regions of Mexico, in areas where it grows always exposed to the sun’s rays. Therefore, in cultivation it is important to place it in such sites so that it can have a good growth.
So, the more sun the plant gets, the better. Myrtillocactus are light-loving and not afraid of direct sunlight. They can safely be placed on the south side of the house, they do not need shade. The only condition is fresh air. If the room is warm, but stuffy, the bush will suffer from a lack of oxygen. In winter, if there are too many overcast days, the culture may need additional light.
Temperature Myrtillocactus grows well at +24-28ºC in summer, and at +15-18ºC in winter. It is not afraid of higher temperatures on hot summer days and can safely withstand values up to +40ºC and even higher. But the cold is dangerous for him. If the temperature drops below 10 °C, it will freeze.
In summer it is possible and even useful to take the vase and shrubs outdoors. In winter, to allow the cactus to hibernate and gain strength for the spring, it is recommended to put it in a cooler environment. But the indoor temperature should not drop below a critical point.
We will only put it in semi-shade for a few weeks if it has been a specimen that has been in a protected nursery, and in spring or autumn – depending on when we bought it – we will gradually accustom it to the sun’s rays.
The soil must be sandy, with very good drainage. From experience I can tell you that it grows well in clay soils with not too many nutrients, but in these cases it is necessary to control watering a lot.
Pot: during its young years it can be kept in a pot with drainage holes and filled with substrates such as pomice, akadama or similar.
How do I protect my plants from the cold?
Plants are covered with styrofoam against the penetration of cold. Depending on the average temperature in the country and the sensitivity of individual plants to low temperatures, for plant containers that do not like the cold, add a special bag with a chemical that releases heat and raises the temperature inside the package (called a heat pack). Additionally, the plant package is filled with fibrous foam, which insulates the contents from the penetrating cold from the outside.
Bilberry cacti does not like high humidity. It prefers dry air or moderately humid air. Being in too humid an environment, its stems may begin to rot at the base. You can occasionally spray the stems with water from a sprayer to sweep away dust, but you don’t need to wet it on purpose.
The optimum humidity is 55 – 60%.
Despite its resistance to dry air, it is still not recommended to place pots with the plant close to heating devices.
Fertilization and watering
For a correct development and a healthy defense system, it is very advisable to fertilize this plant during all the warm months of the year. For this purpose, you can use granulated or powder fertilizers, which are especially indicated for plants that are in the ground, or liquid fertilizers if the cactus is in a pot.
Of course, it is necessary to follow to the letter the indications specified on the package, otherwise the roots would be burned by the excess of fertilizer.
Needs very moderate watering. In summer, the substrate is watered as its top layer dries out. Do not allow water to stagnate on the surface of the soil and in the trays. In winter, watering is significantly reduced.
If the humidity in the room is average, it’s enough to water a little cactus 1 time in 30-35 days. Water should be at room temperature, preferably filtered or well-distilled.
Soften hard water with a few drops of lemon juice or vinegar.
From March to the end of September, fertilize with mineral fertilizers with complex compositions designed specifically for succulents and cacti. Fertilizer is applied once every 20-30 days.
When diluting the fertilizer must not exceed the specified dosage. Soil is used loose, light with neutral acidity. In flower stores sell ready-made substrate for such plants.
If you make the earth mixture yourself, you need to take the following proportions of materials:
- Turf soil – 1 part
- Leaf soil – 1 part.
- Peat – 1 part.
- Coarse sand – 1 part.
Transplant the plant as it grows, about 1 time in 2-3 years. Do not forget about the drainage layer, which is put at the bottom of the pot. If the vase is large, you can do transplanting less often, but annually remove the top layer of soil and sprinkle fresh. All soil renovation and repotting is done in early spring before the growing season.
Keep in mind that too much water in the peat substrate will rot the roots of the plants, so the substrate must be fairly dry. The indicator for the next watering of the plants is a noticeable shrinkage of the leaves.
It is a plant that multiplies by seeds or cuttings in spring or summer:
It is advisable to sow the seeds in seedling trays, for example, to be able to have them better controlled. Although they will also serve the common flowerpots, or even the glasses of yogurt once clean and with the pierced base (make small holes with the tip of a knife or scissors).
Then fill with quality cactus soil, water and finally place the seeds a little buried and as far apart from each other as possible.
To avoid the appearance of fungus, you can sprinkle a little sulfur powder, although it is better to use a fungicide spray if it is summer, otherwise the seeds could be burned.
Fill a pot or flower box with moist soil for sowing seeds or sprouting seedlings. Carefully press the seeds in to a depth twice their thickness. Water the soil to help it settle, then place the box in a warm (19-24°C) and moist place. Myrtillocactus geometricus seeds germinate within 6-8 weeks.
The adult specimens can be multiplied by cuttings without problems. To do this, cut a healthy and strong stem with the help of a hand saw previously disinfected, and then let the wound dry for ten days in a dry place protected from the sun.
After that time, it can be planted in pots with potting compost, or for example with universal substrate mixed with perlite in equal parts.
Time of planting or transplanting: in spring, when the risk of frost has passed.
Pests and diseases
Pests rarely attack myrtillocactus. But the plant can be attacked by spider mites, snails, mealybugs, scabs. Today there is a large selection of preparations that help to quickly destroy the parasites.
Not much more dangerous for the cactus are not insects, but fungi. They breed from excessive dampness and imperceptibly eat the stem. Sometimes the rot affects the roots, making it difficult to save the plant.
The rot takes the form of black, brown or gray mold. If such symptoms are detected, an urgent treatment with a fungicide should also be made.
The cactus gets sick only if the rules of care are severely violated. From overwatering, its stem becomes sluggish, can shrivel. If you do not water the bush for too long, it will begin to shrink, turn blue.
But this is rare, because it can be without water for about 1 year and still not die. The danger to the culture is cold and draught.
For pests, diatomaceous earth is a good treatment, as it is natural and effective; for fungi, however, there is nothing like fungicides.
- “Quilts”. These are white fluffy lumps on cactus stems. Remove the pests with a cosmetic wand soaked in a suitable insecticide;
- Base rot. Brown spots at the base of the stem can occur if you water the plant heavily during the winter. Dry the soil and use a knife to cut off the rotting parts of the stem to where there is healthy tissue. Sprinkle a suitable fungicide over the cut.
The Myrtillocactus geometrizans is an ideal cactus for medium to large gardens, because it has the perfect height and size to be used as a hedge for protection, or to get some privacy.
It is a multipurpose plant, since the flowers, stems and fruits have edible, medicinal, alcoholic beverage and fodder uses. It is also used as a living fence, for firewood, as a fungicide and for construction. It is currently used as a rootstock for ornamental use.
In the Tehuacán-Teotitlán valley, it is one of the most appreciated edible species. It is an abundant species, with a wide distribution, and because of its multiple uses, it is usually protected by farmers.
This is one of the best known columnar cacti. Some classifiers consider it the only species of the genus, of which the others are only subspecies.
To grow Myrtillocactus geometrizans, start with a young plant. Place it in a pot with well-draining soil, and water it regularly. Place the pot in a sunny spot, and fertilize the plant every few weeks. When the plant gets too big for its pot, transplant it to a larger one.
It has a unique shape and produces beautiful flowers and sweet fruits. The cactus is also drought-tolerant and does not require much care.