Star Cactus Guide: How to Grow & Care for “Astrophytum Asteria”

Astrophytum cacti have become very popular in the gardening world thanks to their alluring growth habit and peculiar appearance. While some species are bloaty and common-shaped, others come with a star-shaped structure that can be observed and admired from above. And who would not dream about adding another unusual-looking cactus into their collection?

Astrophytum is a genus that contains exactly six species of adorable cacti in the Cactaceae family. These species can be found in North America regions, such as Mexico and some parts of the United States. However, there are only three of them that are highly cultivated as ornamental houseplants and collectively referred to as Star cacti.

If you want to grow Star cacti, you should know that they are considered somehow difficult plants to cultivate by many gardeners. As a result, these cacti are often grafted along with Echinopsis cacti. But that does not mean that they are picky houseplants! In reality, Star cacti can be grown by any type of gardener as long as they get proper care and lots of love. And guess what! When your cacti are healthy and happy, they will not hesitate to show their gratitude through lovely flowers.

About Star Cactus

• Astrophytum species can be excellent companions to other succulents, cacti, and other houseplants. Their colorful flowers can create beautiful indoor landscapes.
• Sometimes, the Astrophytum cacti are referred to as “living rocks”. The species from this genus are A. Myriostigma, A. Capricorne, A. Ornatum, A. Asterias, A. Caput-Medusae, and A. Coahuilense.
• The first four species mentioned above are individually known as the Bishop’s Cap Cactus, Goat’s Horn cactus, Monk’s hood cactus, and Sand Dollar cactus, respectively.
• Star cacti can do well with minimal care as long as they are provided with plenty of full sunlight and grown in a warm environment.
• Like all cacti, they can store large amounts of water to survive long periods of drought. They are susceptible to root rot, so you need to avoid over-watering them.
• If you want your Star cacti to have the time of their life, plant them in a pot with drainage holes at the bottom that is filled with the well-draining cactus mix.
• They require regular repotting and a nice feeding during their growing season. When the winter has settled in, cut back on fertilizers.
• Generally, they are not poisonous to humans and animals, so you can grow them around your curious family members. But keep in mind that some Star cacti can be pretty prickly.

Star Cactus Features: An Overview

• Like most cacti, they grow at a very slow pace. As houseplants, Star cacti can reach between 2 and 6 inches (5-15 cm) in height, but some of them will grow as much as 6 feet (1.8 m) tall in their natural habitat.
• Ornatum is the tallest and fastest-growing member of the Astrophytum genus. It can grow up to 6 feet (1.8 m) in height and 12 inches (30 cm) in diameter.
• The star-shaped cacti usually have three to seven well-defined and beautiful ribs. With time, more ribs may appear, giving these cacti a swollen, cylinder-like shape.
• Caput-Medusae is a rare and even endangered species. Unlike its friends, this cactus does not look like a star from above, as it contains slender cylindrical stems.
• Their ribs or stems can be colored in various greens, gray-greens, or soft grays. Some specimens have portions covered in wool or white stripes, dots, or hypnotic patterns.
• Depending on the species, their flowers can present different shades of white, cream, or yellow. A. Myriostigma and A. Capricorne are exhibited with an extra dash of orange or red at the base.
• Star cacti bloomings contain tiny seeds. The seeds can be collected from the spent flowers and used in propagation.
• In late spring, their flowers turn into oval berries. They grow in various colors including green, reddish, pink, or gray.
• Although Astrophytum cacti are similar to one another, they bear different flowers, seeds, and fruits.

Growing Star Cactus

We all love cacti due to their cute appearance and low-maintenance style. To grow Star cacti that are healthy and happy both indoors and outdoors, you must remember that these plants have the same needs as most cacti do.

If you already have one or more cacti around, you will be more than pleased to find out that these cacti are no different at all. And if you are at the start of the road, no worries! Everyone can grow cacti successfully without much effort on their part. Stay with us until the end and you will become a cacti-growing expert.

For optimal growth, Star cacti require plenty of full sunlight. Make sure you place your cacti in a location where they can receive at least six hours of bright and direct light daily. If you live in a region with hot climates, you might consider moving your cacti near a sunny window while protecting them from harsh or intense sunlight.

Astrophytum asterias Seeds, From Amazon

Like most cacti, Star cacti love warm temperatures of at least 70 °F (21 °C) during the summer. When the temperatures start to get cooler, there is no reason to move them here and there. Star cacti are quite cold-hardy and can handle well temperatures that drop to 20 °F (-6.6 °C). If the winter is stronger in your area, you must bring your cacti indoors to keep them away from frost.

Star cacti will benefit from a neutral to slightly alkaline potting soil that has good drainage. A coarse, sandy potting mix specifically designed for cacti and succulent should be the ideal growing medium for these cacti. During their active growing season, feed your cacti with a balanced all-purpose 20-20-20 fertilizer diluted in water.

You can help your Star cacti to grow at their best by repotting them regularly. Keep in mind that the process must be done at the beginning of their active growing season in June. When your cactus starts to overgrown its container, remove the Star cactus from its pot and transplant it in another that is one size larger. Fill the pot with fresh cactus mix and be careful not to over-water or feed your repotted cactus too much.

While caring for these little buddies, take some time to inspect them for common intruders. Star cacti are generally pest-free, but they can be occasionally bothered by aphids and scale insects. If you notice any sign of infestation, your cacti can be treated using a cotton cloth dipped in rubbing alcohol. You can also use a good-quality and eco-friendly pesticide to prevent any possible spread.

Watering Star Cactus

We all picture cacti as strong desert babies that can survive even the extreme hot-dry conditions. But Star cacti are a bit different! When it comes to watering, they love to be spoiled with lots of moisture once in a while. Of course, you will still need to allow the soil to dry out in-between waterings as with most cacti. These cacti only want a good soaking after their owner made them go through a long period of hard drought.

A potted Star cactus will need about one watering every month. If you live in a region with hot climates, it may be necessary to water your cacti more frequently. Make sure their roots are not waterlogged, as this may result in root rot and irreversible damage. During the winter, you can water these cacti less often to avoid drowning them.

Humidity-wise, they do well in average indoor conditions. If the air around these cacti is too humid, place them in a room with air vents or use a dehumidifier around your cacti.

Propagating Star Cactus

All cacti are special in their own way, but these unique-looking species are a piece of art. And we understand your inner wish to have more gorgeous companions around. As mentioned above, you can propagate Star cacti by seeds that can be found in their flowers. They can be removed from dried flowers and planted as regular store-bought seeds. This is by far the easiest method of propagation and can show nice results even to beginner gardeners.

Their seeds are pretty fragile, so you should work with them very gently before planting. Also, you need to dig them in potting soil quickly after harvesting, as they have a short life on their own and fewer chances to root. Fill a tray or container with a fresh cactus mix, throw in the seeds, and cover them with little potting soil.

The growing medium must be sealed with plastic wrap to retain humidity and heat. Once the seeds have germinated, you can remove the plastic cover and move the pot to a sunny and warm location gradually. After a few weeks, the baby cacti can be transplanted into their pots and provided with proper care.

In Conclusion

We love growing and propagating Star cacti! They look stunning and can be grown very easily by so many gardeners, novices, and experienced alike.

As long as you provide them with proper soil, monthly moisture, and plenty of light and warmth, these cacti will fit perfectly into your garden collection. And with their superb flowers, how could anyone resist them? Moreover, due to the particular appearance of Star cacti and their easy-to-propagate feature, they could be an excellent gift for holidays.

Do you have a Star cactus? Let us know in the comments below.