Top 4 Reasons Why You Should Grow Cacti in the Genus Astrophytum

If you wish to have cacti in your plant collection, but are scared of their spines, you need to grow cacti from genus Astrophytum. This small genus consists of only 6 species, but have hundreds of cultivars, all of which are beautiful to look at and most grow lovely flowers. The genus name is formed of 2 Greek words – Astron which means ‘star’ and phyton which means ‘plant’. Therefore, their common name in English is ‘star cactus’ due to their star-like shape. But they also have another common name – ‘Sand Dollar Cactus’ because its flat spineless body also resembles a sand dollar. However, there is quite a lot of variety in shape, texture, form and spininess or spinelessness between the species and cultivars. They are native to Southern Texas and Mexico. They occur in areas that receive hot humid summers and short dry winters.

Plants in the Astrophytum genus tend to grow individually. They have columnar or spherical green branches that are usually thickly covered with white fine tufts of hair. But they can even be sometimes totally bald. There are often 4 to 10 (rarely 3) very marked ribs on the shoots. Ribs are not divided into cusps. Also, they have large areoles that stand near each other, but don’t merge. Let’s see top 4 reasons why you should grow Astrophytums if you wish to have a beautiful cactus collection.

1. Low Maintenance and Compact

Astrophytums are low-maintenance cacti with a distinctive appeal. They are ideal for those having a busy schedule and often tend to forget watering their plants. What’s more, you can enhance the beauty of any space in your home or yard with Astrophytums because these cacti come in unique shapes and patterns. They don’t even take up a large space, as they are compact and you can easily place them in small corners which makes them suitable for small apartments and gardens.

Cacti in the genus Astrophytum often reach a height of up to 1.5 m (4.92 ft). Some of the species hardly grow more than a few inches but their diameter can reach up to 15cm (6in). These cacti produce large, funnel-shaped flowers that are yellow or yellow with a red center. These develop at the ends of the shoots and open during the day. Each flower blooms for around 2 days. There are pointed scales on the pericarpal. Seeds are shaped like caps with a diameter up to 2.5mm (0.4in) and have a brownish black almost smooth coat. The hilum is dipped down and the edge is rolled towards it.

2. Easy To Grow and Long-Lived

Most species in the genus Astrophytum have a slow growth rate, but they are generally easy to grow. Just fulfil their basic needs and you are good to go! They can adapt to a variety of conditions like various levels of light and temperatures. This makes them easy to grow. If you provide them proper care, Astrophytums can live for several years to make you enjoy their unique looks, blooms and overall visual appeal.

3. Rewards You Constantly with Blooms

The best thing about cacti in the genus Astrophytum is that during their blooming season (spring) if they are happy, they keep blooming all summer long and even during fall. If you fertilize them if the growing conditions are best you’ll be rewarded with rounds after rounds of flowers that will ultimately turn into fruits in the form of red or olive-green berries that contain several seeds.

4. Easy to Care For

Light

Astrophytum cacti enjoy some direct sun. However, they actually do well in indirect bright light. Hence, it’s advisable to place these cacti in locations where they can receive some nice morning sun and even a few hours of afternoon sun and then indirect sun for the remaining day.

Remember that these cacti can also tolerate medium light. Thus, a nice medium-light location in your house somewhere in the middle of a room with a regular size window will be best to make these plants happy. You can even place them under grow lights.

While placing it outdoors, remember to avoid a spot which receives too much direct sun, because then the plant will be sunburnt.

Soil

To grow Astrophytum cacti, well-draining cactus mix is essential so you can prevent root rot. You can make even your own cactus mix by combining some coarse sand, peat moss and perlite. Strictly avoid water-retentive heavy soils.

Watering

You should water Astrophytum cacti sparingly and only when the soil is completely dry. Reduce watering remarkably during winter dormancy. It’s best to apply soak and dry method. In this, water generously when you notice the top inch of soil is dry. Wait till it’s completely dry after which only water again. These cacti can’t withstand standing water or mushy soils. They are resistant to drought and dry soils. With the weather turning cool, you should keep these cacti dry.

Temperature

Astrophytums love warm temperatures during the cooler, dry temperatures at night. They can stand summer temperatures up to 70 to 95 degree F (21.11 to 35 degree C) and winter temperatures up to 40 to 70 degrees F (4.44 to 21.11 degrees C). Astrophytums thrive in dry and semi-arid climates. You can overwinter your indoor Astrophytums in a cool, dry room with some sunlight.

Fertilizing

It’s advisable to apply a balanced cactus fertilizer once a month during the Astrophytums’ growth period. Avoid fertilization during winter dormancy. And strictly avoid over-fertilization as it can lead to overgrowth and ultimately weak plants.’

Other considerations

Pests and Diseases

You should protect your Astrophytums mainly from spider mites, scales and mealy bugs. Also avoid overwatering, soggy soils and poor drainage as these can cause fungal infections and/or root rot.

Propagation

You can propagate Astrophytums easily with seeds or offsets.

You can propagate Astrophytums by sowing the seeds in a well-drained cactus soil. You should water the soil until the seeds sprout.

For propagation with offsets, remove the offsets carefully from the mother plant and plant them in individual pots.

Popular Species

Astrophytum asterias

Astrophytum asterias is known as miracle astrophytum. It has a rich history since it occurred in the wild and then was taken to Japan in the 1880s. it’s a small-sized, round, spineless and thick cactus. Its body is disc-shaped and has 8 greenish-brown ribs. This cactus once occurred abundantly all through Texas and Mexico, but as its original habitat was heavily destroyed, it has now remained limited to a small spot near Rio Grande City.

Astrophytum myriostigma

The cactus you might know popularly as Bishop’s Cap, Bishop’s Hat or Bishop’s Miter Cactus is actually Astrophytum myriostigma. It’s a spineless cactus species marked with three to seven (often five) prominent vertical ribs which explain the cactus’ shape when young why it’s called star plant. The number of ribs may increase as the plant ages and the plant may become cylindrical in shape, becoming up to 70-100 cm (2’4” – 3’3”) tall and 10-20 cm (4-8 in) in diameter. This plant has been honored with the Award of Garden Merit by the Royal Horticultural Society.

Astrophytum ornatum

This Astrophytum species too is commonly called as Bishop’s Cap and also as Monk’s Hood. It is the tallest and largest Astrophytum species. The Central Plateau of Mexico has this species in abundance. It grows singly and has a cylindrical form. It may reach a height of 2m (6.6 ft) and a width of 30 cm (12 in) in its habitat. It has many woolly flecks for protection from the harsh sun. It rewards you with flowers all through the summer. Flowers are canary yellow and are 7 to 8cm (2.75 to 3.14in) long. The beauty of A. ornatum is that it’s easy to grow if you offer it a well-drained soil and is robust and resistant to root rot. If well-established it’s also cold tolerant to a temperature up to 25 degree F (-4 degree C). When grown in filtered light or shade, it develops a dark green color. This cactus species too has been honored with the Award of Garden Merit by the Royal Horticultural Society.

Astrophytum coahuilense

You may confuse A. coahuilense with A. myriostigma as there is a big resemblance between the two species. There are some differences though. A. coahuiense has a five-ribbed structure and its epidermis has more softer trichomes than that of A. myriostigma has. This cactus is native to Mexico, especially the southwestern areas of Coahuila and Durango. Soils consisting of mainly lime gravel and sand are its favorite. A. coahuiense reaches up to 10 cm (3.93in) (sometimes even 20cm (7.87in)) of height. It grows very attractive flowers that are yellow with a typical red center. However, it can also be totally yellow or red. It ultimately turns into olive-green fruit that contains up to 200 seeds at the basal opening.

Astrophytum capricorne

A. capricorne is also known as Goat’s Horn Cactus. It’s native to the Coahuila regions of Northern Mexico. It’s ball-shaped or oval and reaches a height of up to 50cm (20in) and width of 10cm (3.9in). it has 7 to 9 conspicuous ribs and very long twisted spines. It’s due to these curved spines that resemble goats’ horns, this cactus is commonly known as goat’s horn (capri means goat and corne means horn). Its color is grey-green and in summer it grows lovely yellow flowers with a red center. It can be easily grown from seeds as an ornamental plant. Although A. capricorne is tolerant to cold temperatures, you should grow it in a warm, sheltered place which doesn’t receive freezing cold in the winter. Astrophytum capricorne has won the Royal Horticultural Society’s Award of Garden Merit.

Bottom Line

Astrophytums are ideal for those who wish to start a cactus collection. These are hardy plants tolerating various conditions. Being drought resistant, they are ideal for gardeners who have busy schedules and often forget to water their plants. What’s more, their many cultivars have interesting shapes and structures, and lovely flowers that turn into attractive fruits. They are also easy to propagate. In short, Astrophytums are very versatile. So, why don’t you start your cactus collection with them to get rewarded with a striking visual appeal for your home and garden? Get interesting information about various species of cacti and succulents on this website and don’t forget to leave a comment in the comment sections!