Cacti have the best of both worlds: they’re easy to care for, and they’re among the weirdest-looking plants you can decorate your home or garden with. They’re also good plants to have if you travel a lot and won’t be around to take care of them, as they often thrive on neglect. Some are fast-growing, while some take their time, and there are a few types which are quite long-lived, so you may find as your life grows, you may be moving houses with them a few times!
So here’s the basics. As a rule, cacti love sunlight, hate what you’d call good soil – which means they require specialist succulent/cacti compost or sand, not all-purpose compost or compost that’s full of nutrients, otherwise they’ll rot – and they can go for months without water, depending on the type. They like the dry conditions homes provide where other plants will die. Anyone who comes over will be suitably impressed by your plant-raising skills, whether you have a green thumb or not.
It’s always worth checking the compost your new plant friend is sitting in. Often, they can be sold within a cheaper type of compost and are only meant to last the season they’re sold in, so changing the compost if needed, will do wonders.
Cacti are part of the Cactaceae genus, and vary wildly in size and appearance. Most grow in desert-like environments, where they have adapted to store the little water they get in order to survive.
Cacti and succulents are related, but succulents refer to a type of plant which has thick flesh (usually the leaves) which stores water. Almost all cacti are classed as succulents, but not all succulents are cacti. Cacti mostly have very little leaves, and they’re nearly all from America. Cacti also have areolas – their defining characteristic – which are small spots that grow spines or hair, but some types of astrophytum lack spines and hair.
While they grow really well outdoors in warm, dry climates, they can also do well inside as houseplants with adequate light. They add character and personality to any room, and if cared for properly, some types will flower. Some cacti are very long-lived, compared to other plants, and as houseplants, they may live for a couple of decades, and outside, they can live anywhere up to two hundred years.
Moon Cactus (Gymnocalycium mihanovichii)
Also known as chin cactus, Hibotan cactus.
The moon cactus is a popular type for outdoor spaces. This type of cactus is a mutant – because it completely lacks chlorophyll, it needs to be grafted onto one that can produce it in order to survive, which is usually the hylocereus cactus, and the Frankenstein result is known as the moon cactus. You can identify the part of the plant which doesn’t produce chlorophyll, as it’s not green – it can appear neon orange, purple, yellow, pink, or red, on top of the grafted, hylocereus cactus, and looks a bit like a lollipop. While they can grow up to eight inches in diameter, they only reach about half an inch in width. As this cactus is grafted, it only lasts a few years, as the base plant grows faster, and the two split.
Popular types of moon cactus plants include:
- Gymnocalycium mihanovichii var. friedrichii ‘Hibotan’
- Gymnocalycium mihanovichii var. friedrichii ‘Akaguro Hibotan-Nishiki’
- Gymnocalycium mihanovichii var. friedrichii ‘Pink-Kuro’
- Gymnocalycium mihanovichii’ Hibotan Nishiki’
Bunny Ear Cactus (Opuntia microdasys)
Also known as the neon cactus, golden cactus, bunny cactus, polka dot cactus, or the angel’s wings cactus.
This cactus forms pad-like stems in pairs, which resembles a rabbit’s ears. There’s usually a lot of novelty in growing cacti, and it helps when they’re so easy to care for, which means the novelty doesn’t wear off.
Bunny ear cacti grow from 40-60 cm tall, but outside in conditions similar to its native habitat, it can reach 2-3 feet tall, spreading from 4-5 feet wide.
These particular cacti grow glochids, which are hair-like spines which are thinner than human hair, and will cause skin irritation, so you can either remove these, or wear thick gardening gloves when handling this plant – which should be nearly never. It’s rare for a Bunny ear to flower, but if you’re lucky enough, it will bloom yellow flowers during summer.
This cactus is native to Northern and Central Mexico, and if you grow it in a container, it needs the best drainage possible. Like with most houseplants, pests include scale insects and mealybugs, but this is fairly easy to treat, provided you separate the affected plant to stop those villains from spreading to healthy plants.
Subspecies of bunny ear cacti:
- Opuntia microdasys subs. rufida
- Opuntia microdasys var. albispina
- Opuntia microdasys var. pallida
- Opuntia microdasys var. pallida f. cristata
Star Cactus or Sand Dollar Cactus (Astrophytum asterias)
Also known as star cactus, sea urchin cactus, star peyote
Astrophytum is a family of six species of Cacti, which translates from Greek to mean “star plant”. These unusual looking guys hail from Mexico, and small parts of Texas.
They’re slow-growing and spineless, and grow to about 6cm in height, and a maximum 15cm diameter. If you look at them from above, you’ll notice the star shape they’re named for.
You’ll be treated to flowers from March onwards until June, which is summer in its native habitat, which are usually yellow with a contrasting orange or red center. Each flower can grow up to 15cm wide, and opens during the day, closing at night, and can later produce fruit.
Popular types of astrophytum asterias:
- Astrophytum asterias ‘Super Kabuto’
- Astrophytum asterias ‘Hanazono’
- Astrophytum asterias ‘forma nuda’
- Astrophytum asterias ‘multicostatum’
Old Lady Cactus (Mammillaria hahniana)
Also known as birthday cake cactus, old lady pincushion cactus
Mammillaria hahniana is a cactus native to central Mexico, and is one of the most popular cacti which you can grow indoors. This is a much taller cactus than the astrophytum, as it grows up to 4 inches tall, and 5 inches wide.
Like many cacti, the old lady cactus will start off globular, and will grow cylindrical as it gets older, and the hairs get longer and thicker. It’s also recognizable for the crown of reddish-purple flowers which form at the top during spring and summer.
Popular varieties, subspecies, and other forms include:
- Mammillaria hahniana var. giselana
- Mammillaria hahniana var. werdermanniana
- Mammillaria hahniana subs. bravoae
- Mammillaria hahniana subs. mendeliana
- Mammillaria hahniana subs. woodsii
- Mammillaria hahniana f. albiflora – this cactus has white flowers
Spiny Pincushion Cactus (Mammillaria spinosissima)
Also known as Irish red-head cactus, read-headed Irishman cactus
Mammillaria spinosissima or the spiny pincushion cactus, is also a well-known plant, which is native to Mexico, Guerrero and Morelos in particular, where the elevation ranges from 5,200 – 6,200 feet.
The common name comes from the needle-like spines which can be white or reddish-brown, and the underlying stems are cylindrical, which can range from 7-30cm tall and 6-10cm diameter depending on the age of the plant.
If the plant is cared for properly, purple or pink flowers will crown the plant in spring.
Popular varieties, subspecies, and other forms include:
- Mammillaria spinosissima rubrispina
- Mammillaria spinosissima ‘Un Pico’
- Mammillaria spinosissima forma Mostruosa
- Mammillaria spinosissima pilcayensis
Feather Cactus (Mammillaria plumosa)
Also known as golf ball cactus
Mammillaria plumosa, or the feather cactus, is native to the Northeastern parts of Mexico. The stems grow in clusters, and reach 5 inches tall, and about 16 inches wide, and 3 inches in diameter.
While covered in white ‘feathers’ which is where the name comes from, these ‘feathers’ are soft spines, and help shade the plant from losing what little moisture it’s able to gain.
Flowers on a feather cactus can range in color, depending on the variety. The blooms come in pinks, whites, or a greenish yellow, and appear in late summer, bringing a lovely fragrance.
A popular variety is the mammillaria plumosa var. roseiflora, which features pink flowers, and the rest of the plant’s appearance is identical.
Golden Barrel Cactus (Echinocactus grusonii)
Also known as mother-in-law’s cushion, golden ball cactus, barrel cactus
Echinocactus grusonii, or the golden barrel cactus, is recognizable by its circular, ribbed sole stem, which feature prickly yellow spines. Wooly, thick white hairs cover the very tops of the plant. It’s native to east-central Mexico, and is endangered in the wild, where it grows in volcanic rock.
Like most cacti, the golden barrel cactus is a slow growing plant, but it can also tolerate lower light conditions, which makes it more suited to the indoors than other species of cacti.
Found in the wild, they can reach up to 130cm tall, and width is about 90cm.
Flowers can also be produced by this plant, though this only happens to older plants, and doesn’t always happen if it is indoors.
Popular varieties, subspecies, and other forms include:
- Echinocactus grusonii cristata
- Echinocactus grusonii var. albispina
- Echinocactus grusonii var. brevispinus
- Echinocactus grusonii var. brevispinus f. cristata
- Echinocactus grusonii var. intermedius
- Echinocactus grusonii f. monstruosus
- Echinocactus grusonii setispinus mostruosus
Totem Pole Cactus (Lophocereus schottii var. mostruosa)
Also known as monstrous whisker cactus, totem cactus
Lophocereus schottii var. mostruosa or the totem pole cactus is another slow growing cactus. This is a cactus that grows like a tall, slim column, and is native to Arizona and northwestern Mexico.
Adult totem pole cacti can reach heights of a maximum 6 meters outside (hence the Latin for monstrous), with diameters ranging from 10-12cm, and resemble totem poles. They feature irregular-shaped ribs with parts that swell. Pale pink flowers bloom at night, though these are ornamental as the totem pole cactus doesn’t set seed. To get the most out of a totem pole cactus, they need full sun.
Fairy Castle Cactus (Acanthocereus tetragonus ‘Fairy Castle’)
Also known as green finger cactus, or fairytale castle cactus
Acanthocereus tetragonus or the fairy castle cactus was originally classified as Cereus tetragonus.
It has an unusual shape where ‘turrets’ or branchlets peek out from the main column, which is where the name comes from. This main stem has five sides, and white spines. While flowers can be rare, they open from midnight until the sun rises, and attract hummingbird moths. It can also produce fruit.
When mature, it can reach 3 meters tall.
In the wild, you’ll find it in sandy, hot coastal habitats, often coastal ‘hammocks’ in North and Central America, northern South America, and the Caribbean.
Commonly sold as houseplants which bloom in red, pink and white, these cacti are named after the season they flower in, including the Easter cactus, Thanksgiving cactus, and the Christmas cactus.
If taken care of properly and provided with the right conditions, holiday cacti can live for 20-30 years!
It’s easy to mistake the Thanksgiving cactus and the Christmas cactus, as they have very similar appearances, and both come from the Schlumbergera genus. The way to tell them apart is to look at when they bloom and how long the flowers last, and the way their stem segments are shaped.
Thanksgiving Cactus (Schlumbergera truncata)
Also known as false Christmas cactus, holiday cactus, crab cactus
Schlumbergera truncata or the Thanksgiving cactus hails from the forests of Brazil. It blooms around Thanksgiving, hence the name. While called a cactus, it’s not a true cactus, as it is a plant that lives off other plants. Flowers that form are similar to those produced on a Fuchsia, though these are yellow, white, pink, or red. The leaves have serrated edges, and the plant can grow to a maximum of 12 inches tall, spreading to 24 inches.
This cactus should not be left to dry out, though excess water can lead to root rot. Because it is a plant that lives off other plants, the roots are exposed to the air, and gains a lot of moisture from the air instead of soil.
Christmas Cactus (Schlumbergera bridgesii)
Also known as holiday cactus
While the Thanksgiving cactus and the Christmas cactus can be confused, you can tell them apart by the shape of the stem segments.
The Christmas cactus has smooth, flattened stem segments, which are rounded in the margins. While the flowers are a similar shape, the Christmas cactus comes in red or pink.
The Christmas cactus also flowers later, usually during Christmas time, and is shorter than the Thanksgiving cactus, at a maximum height of 10 inches, but the same spread of 24 inches.
The Christmas cactus comes from the southeastern area of Brazil, in particular the coastal mountains. It needs temperatures between 60-70 degrees F to survive.
Easter Cactus (Rhipsalidopsis gaertneri)
Also known as Whitsun cactus, holiday cactus, spring cactus
Rhipsalidopsis gaertneri, Hatiora gaertneri, or the Easter cactus, comes in more colors than the other two holiday cacti. Flowers can be white, red, orange, peach, pink, or purple. They’re also wider than the flowers the other two holiday cactus plants produce. It likes bright light where it won’t get direct sun, and wants repotting in spring every two years.
Like the other holiday cacti, it requires slightly moist soil, but not sodden soil which would lead to disease and the death of your plant. It also requires some humidity, which, while a normal method of increasing humidity would be to mist the leaves, it’s better to place it in a tray filled with pebbles and some water. Misting succulent leaves will lead to the leaves rotting.
It grows up to 25 inches tall, and spreads more than the other two at 30-40cm diameter. It’s also native to southeastern Brazil, where it would grow off other plants in a reasonably humid environment.
The Easter cactus has flattened stems, which have oblong segments and smooth edges, but also features soft hairs in between these. They’re pale green when they’re young leaves, and grow darker with age.
It’s easy to propagate these holiday cacti. Make sure to do this during the growing season. Take a stem cutting which has at least two stem segments but no more than five, and pop them somewhere cool and dry to heal the cut. Place the bottom tip in water and somewhere that gets bright, indirect light, and you should see roots in six to eight weeks.
Once these plants have finished flowering, you can force a new cycle, by cutting back on the watering, reducing the light, and temperature. Give it 12-14 hours of darkness a day, and keep the temperature to around 50-55F, away from anywhere drafty, as this could kill your plant. Do this for six to eight weeks. This forces the plant to go dormant, and while it can take up to 12 weeks, it will bloom again. Once it starts to flower again, move it back to a bright spot that doesn’t get direct sunlight, or the intense rays could cause the flowers to drop!
If your holiday cactus is not blooming, it’s usually a sign that the conditions it’s living in are less than ideal. While the soil needs to be kept damp, you may be overwatering it. To bloom, these plants need less water so it can tell the ‘season’, where it will start to prepare for flowering. Artificial light can also disrupt the plant, especially when it needs 12 hours of darkness in its dormancy period. They also require a significant drop in temperature in order to start the flowering process, and if your plant sits near a south-facing window – this is too warm!