How To Take Care Of Your Astrophytum Asterias – Star Cactus

The Astrophytum asterias, or also known as the sand dollar cactus or the star cactus, is a small star shaped cactus that resembles a sand dollar.

This small plant blooms a beautiful flower and is a great plant for adding life to homes for those who don’t want to worry too much about the care about they have to give a plant, great for beginners and all cacti lovers.

However, this tiny little fella is an endangered species of cacti and is very vulnerable to extinction. Many people and groups are teaming up together to save the Star Cactus and preserve it for subsequent generations to enjoy.

To work towards saving this plant from extinction, one must learn how to properly take care of it and propagate it, but there is not much information on it online and it is hard to find the true and anything that’s actually effective.

So, we have gathered a detailed list of how to take care of the Star Cactus, how to propagate and much more! Together with this information, we can enjoy gardening the Star Cactus and hopefully work towards saving it from extinction.

What Is The Astrophytum Asterias?

The Astrophytum Asterias, or the Star Cactus, is a small, round, and plump spineless cactus of the Astrophytum genus of the Cactaceae family.

Native to some parts of Texas and Mexico, this endangered species is a round green ball with dots and speckles, accompanied with white scales that go across the cactus diagonally meeting at the center where it blooms a beautiful white daisy-like flower with a yellow center.

The cactus also sprouts oval fruits that vary from green and to dark purple-magenta when ripe, coated with white wooly hairs outside. This edible fruit is sweet with small seeds inside that are also edible.

Astrophytum Asterias

What Are The Common Names Of The Astrophytum Asterias?

Although there are many common names of the Astrophytum Asterias, we will only go over the most commonly used of the common names.
The most commonly used are “star cactus”, “sand dollar cactus”, “sea urchin cactus”, and “star peyote”.

Before we get into the common names and their meanings, let first start with the plant’s scientific name.

Astrophytum, the genus, derives from the Greek word Astron, meaning a “star” and phyton, meaning “plant”. When put together, Astrophytum breaks down to “star plant” referring to the cacti’s noticeable star like characteristics.

Asterias, the species of plant, is also a genus of Asteriidae family of sea stars. The name refers from the Greek word Asteria, meaning “of the stars” or “starry one”. A lot of the common names of the Astrophytum asterias are derived from the plant’s star appearance.

The common name “Star cactus”, refers to the plant’s genus, Astrophytum, derived from the Greek words Astron and phyton. when put together they translate to “star plant” as mentioned above.

Along with the Star cactus common name, Sand dollar cactus also refers to the plant’s appearance, but not to a star. In fact, it refers to the plant’s un-bloomed and dormant state from above, resembling a sand dollar, a species of flat sea urchin.

Speaking of sea urchin, the plant is also commonly named as the “sea urchin cactus”. This common name refers to the cactus’ prickly appearance resembling the spiky ocean critter that can be quite painful to step on.

And finally, “star peyote”. A peyote is a small, spinless cactus with psychoactive alkaloids. The name derives from the Spanish word of the Nahuatl peyōtl, Nahuatl meaning “caterpillar cocoon” and peyōtl meaning “to glisten”.

History Of The Astrophytum Asterias

The first recorded information on the discovery of the Astrophytum asterias goes back all the way to 1842 with a man named Karwinsky Baron in a German expedition in the Tierra Caliente area in the state of Tamaulipas, Mexico.

 A tale once said that Baron found the cactus on accident when his sombrero flew off from a gust of wind and landed on a Star Cactus.

The plant was sent to Munich, Germany in 1843 where Joseph Gerhard Zuccarini first described it in 1845 as the “Echinocactus asterias”, but later changed to the Astrophytum Asterias by Charles Lemaire in 1868.

For unknown reasons, the Star Cactus disappeared from the Tierra Caliente region and took nearly 70 years to appear and to be rediscovered in Mexico. It is now found in the new habitats of Barretillas (Nuevo Leon) and Ciudad Guerrero (Tamaulipas).  

In 1923, Czech botanist Alberto Vojtěch Frič found the plant again in Tierra Caliente and took 2000 copies, with three-quarters frozen, overseas to Central Europe.

With all of this removal, you can see why the Astrophytum asterias is labeled as an endangered species of cacti, so much so that Mexico passed a law in 1931 that prohibited the removal of any and all samples of the endangered species.  

In 1933, a small population of the Star cactus was found in Texas, but do to intense agriculture and levies, that population had all but disappeared by 1935.  Later on in 1967, another population was found near Roma in Starr County, Texas.

From this, Texans called these newfound population as the subspecies Texensis, but this subspecies has not validated by credible botanists to make it official yet.

Later in the 1980s, several cultivars appeared in Japanese collections of private collectors and are said to be being cultivated there to this day.


How To Take Care Of Your Sea Urchin Cactus?

To successfully take care of a Star cactus, you need to learn what are the best soil types, fertilizer, water, sunlight and temperature that best fits the need for this particular cactus.

Like many cacti, the Star cactus prefers grainy, porous soil that water can easily pass through and soak up. Use a regular cactus mix or a draining succulent mix. Avoid using organic soil mixes because they attract pests and increases the risks of rot due to allowing standing water.

For better water distribution, use a rocky or grainy topdressing to your soil like pebbles, river rocks, perlite, and others.

Water your Star Cactus every 3 to 4 weeks in its growing seasons of the spring and summer, then water rarely in the winter only when the soil is bone dry.

You can tell if you’re over watering your cactus or not giving it enough by looking at the plant’s physical features; If the cactus feels mushy or looks discolored, it means that you’re over watering it, if it looks shriveled, flattened, and brown, that means that you’re not giving it enough water.

Along with the right soil and water, the best recommended fertilizer to give to your Star cactus is a balanced diluted one such as a dilution of fish or compost in its water for the spring.

Give your cactus a little bit of fertilizer during the spring and avoid giving it anymore during the rest of the year.

Star Cacti love bright direct sunlight, so it is best to put it out on a bright windowsill next to a window or leave it outside in the sun. As you know, the amount of sunlight that the cactus receives may vary with where you live so you may need to make adjustments.

Like with all things, too little or too much will affect the cactus. You may find your cactus is experiencing sunburn if it turns brown or yellow, and if your cactus’ original dark green color starts to fade and turn lighter, it means that it is not getting enough light.

The ideal temperature to expose your Star Cactus to is above 70˚F during its active growing period from Spring to Summer. During the Fall and Winter when it goes dormant, it is best to expose it to temperatures between 45˚F – 55˚F.

However, if you live in a place where it gets cold, it’s best to have your cactus in a portable container so that it can be switched from outdoors to indoors. The lowest temperature that the Star Cactus can be exposed to is 25°F, anything lower than that is dangerously cold for the plant and it could die.

What Is The Best Soil For Growing Your sand dollar cactus?

The best soil to use for growing your Star Cactus is a grainy porous soil like cactus or succulent mix. Avoid using organic soil mixes, they attract pests and increase risks of rot. For better water distribution in your soil, use a topdressing on the surface of your soil like lava rock, river rock, perlite, and others.


How Often Should I Water My Sea Urchin Cactus?

You should water your Star Cactus infrequently in the spring during its growing season around once every 2 to 3 weeks, and rarely in the winter when it is dormant (only when the soil is bone dry). You can tell if you’re over watering or not watering your cactus enough with the symptoms shown below.

Over watering: mushy or discolored.

Under watering: shriveled, flattened, or brown colored.

What Is The Best Fertilizer To Use For My Star Cactus?

The best fertilizer to use on your Star cactus is a balanced and diluted fertilizer, like 20% fish fertilizer mixed into water. Give your cactus only a little bit of fertilizer during its growing season and don’t give it anymore for the rest of the year.

How Much Sunlight Should I Expose My sand dollar cactus To?

Cactus needs lots of direct bright sunlight, so depending on where you live and how much direct sun you get there, the Star Cactus may need to be positioned or placed in an area that gets at least 6 hours of direct sunlight per day.

Here are a couple of guidelines to help you out.

Too much light: Cactus will turn brown or yellow.

Not enough light: Cactus’ original dark green color turns to a much lighter shade of green.

What Is The Ideal Temperature For Star Cactus?

The best temperature for the Star Cactus is between 45˚F – 70˚F, anything lower than 25°F is dangerous for the plant to be exposed to.

If temperatures where you live tend to get cold, it’s best to put your cactus in a portable container so that the plant can be transferred from outside to inside, or just keep it inside all the year round.

Is The Star Cactus Poisonous To Pets?

The Star Cactus has no reported cases of being toxic to pets, however you should be careful with the plant around animals, so it’s best to keep it up in a place from your furry friends’ reach.


Is The Star Cactus Edible?

The Star Cactus produces edible oval fruits that tend to turn from green to magenta when ripe and are covered in needles. Inside, the fruit has small black seeds that are also edible but hard.

In conclusion, this fruit is edible, tasty, and painfully prickly unless the needles are removed.

Is The Star Cactus Seasonal?

The Star Cactus is a seasonal plant whose growing season is in the spring, blooms in the summer, and goes dormant in the fall and winter.

Is The Star Cactus An Endangered Species?

The Star Cactus is an endangered species of cactus. Since its discovery, the plant has been harvested and destroyed by agriculture and levies, thankfully, the cactus is seeing a slow recovery with more and more populations growing in parts in Texas and Mexico.

How To Propagate Star Cactus?

The Star Cactus can be propagated by seeds that can be bought and collected from dried fruits. However, be very careful when you handle the seeds because once dried they are fragile. Carefully place the seeds in a tray or pot of soil filled with cactus potting mix, barely covering the seeds with potting medium.

What Are The Most Common Pests And Diseases Of The Star Cactus?

The most common pests and diseases that the Star Cactus is vulnerable to are scales, mealybugs, and rot.

Like all succulents, the Star Cacti are vulnerable to rot due to over watering or standing water. To avoid rot, keep your watering in check by keeping in mind the golden rule of succulent watering; keep your plant dry between watering. If your cacti’s soil feels dry, then you should water it, depending on the season.

Scales feed on the sap of plants, and your cactus will appear shiny and feel sticky from droplets of sugary liquid exerted from the scales. To get rid of them, you can prune your plant, pick them off by hand, and dab them with alcohol or neem-based leaf shine to help reduce infestation numbers.

Mealybugs are one of the most common pests found on plants. High nitrogen levels and soft growth in plants are what cause them to infest, along with infestation due to over watering and over-fertilizing your plants. You can get rid of them by applying alcohol with some dish soap on cotton swabs each day until they are gone.