Cacti are versatile plants that can thrive in various climates and conditions, making them great choices for indoor gardening. With a wide selection of cactus species available, there are plenty of options to choose from when selecting the perfect houseplant. Cacti offer a unique beauty that is especially striking when they bloom, and their diverse shapes, sizes, and colors make them an exciting addition to any plant collection. Additionally, in hot and arid regions, many cacti species thrive outdoors. While some cacti prefer warm and humid environments that are typically found in tropical regions.
Caring For Different Types of Cactus
Cactus plants are a great option for those looking for low-maintenance houseplants. Their hardiness allows them to thrive with minimal care, making them an ideal choice for busy homeowners. Indoor cacti typically need only a small pot and a bright window sill, with occasional watering. Popular indoor cactus varieties include Bunny Ears, Christmas Cactus, Moon Cactus, and Balloon Cactus.
Cacti are also well-suited for outdoor cultivation in warm climates. Planting different types of cacti in your garden or rock garden can add color and interest to your outdoor space. Arizona Barrel Cactus, Prickly Pear, and Old Man Cactus are among the best desert cactus varieties for outdoor cultivation. These types of cacti can thrive in hot, arid environments with minimal watering, making them a great choice for gardeners in desert regions.
Cactus Plant Features
The cactus plant family (Cactaceae) includes a variety of unique succulent plants that thrive in dry conditions. Cacti come in various shapes and sizes, and they are all indigenous to the Americas. Despite being classified as succulents, cactus plants differ from many other types of succulents. Instead of storing moisture in their leaves, cacti keep it in their stems.
Cactus stems can range in color from light green to dark green, and their photosynthesis process is one of their distinct characteristics. Unlike most plants, cacti absorb carbon dioxide at night when the temperature is lower. As a result, they experience less evaporation on hot days.
Following significant rainfall, several desert cactus species’ stems have ribs that enable them to expand. Cacti’s spines are another feature that sets them apart. Some cactus spines can cause discomfort if they prick your skin. However, certain cactus varieties have softer spines to defend themselves. For example, the Prickly Pear has hair-like spines that may cause discomfort if they become embedded in your skin.
Cactus Flowers
One of the most fascinating features of all cactus species is their flowers. Even though they only bloom for a short period, cactus flowers can be incredibly stunning. They come in a variety of colors, ranging from deep pinks to gorgeous shades of red. Additionally, some cactus varieties produce blooms in yellow, orange, white, and burgundy.
Cactus plants are known for their unique ability to bloom, which sets them apart from other types of succulents.
How to Identify Cactus Varieties
The unique shapes, blooming habits, and spines or hairs are key identifiers for different types of cacti. Cacti can take on various shapes such as spherical, columnar, cylindrical, and disc, and they have spines or soft hairs that develop in distinctive locations. The time of year a cactus blooms can also help identify its species.
As houseplants, cacti are small succulent plants that thrive in sandy soil and full sun exposure. However, it’s essential to handle cactus plants with care due to their spines or hairs. Some cactus species have hard, pointy spines that can puncture the skin and cause harm, while even fuzzy-looking cacti with soft barbed spines can cause skin irritation.
Types of Cactus (With Pictures and Names) – Identification Guide
So now that you are aware that cacti are easy to maintain blooming plants, let’s explore the various kinds of cacti available for indoor and outdoor cultivation.
Bunny Ears Cactus (Opuntia microdasys)
The Bunny Ears cactus, scientifically known as the Opuntia microdasys, is a popular houseplant due to its adorable appearance. This cactus species, native to Mexico, can thrive both indoors and outdoors, making it a versatile addition to any plant collection. The Bunny Ears cactus is also referred to as Angel’s Wings or Polka-Dot cactus, among other names.
The Bunny Ears plant features green pads that resemble rabbit ears, and can reach a height of 15 to 23 inches (40 to 60 cm) as an indoor cactus. Like many cacti, the Bunny Ears is a slow-growing plant that takes several years to reach its full height. This flowering cactus may produce yellow flowers from time to time.
The Bunny Ears cactus is covered in fine hair-like spines known as glochids, which can cause significant skin irritation if they get embedded in the skin. The white or yellow glochids give the plant a dotted appearance similar to polka dots. Interestingly, one of the best ways to remove cactus glochids from the skin is by using sticky tape.
Cactus Identification: The flat, disc-shaped stems of the Bunny Ears cactus are covered in little tufts of tiny hairs and are easily identified. Because of the rabbit ears look, this cactus is very easy to identify.
Old Lady Cactus (Mammillaria hahniana)
The Old Lady cactus is a spherical cactus with spikes and fine spines that can be grown as a houseplant. This cactus resembles a large pincushion and can reach a diameter of 20 inches (50 cm) and a height of 10 inches (25 cm).
One of the fascinating features of the Old Lady cactus is its reddish-purple blooms that may appear from time to time. These small blossoms bloom in a circle around the crown of the cactus. Since this desert cactus requires a hot, dry environment to thrive, many people have had success growing it indoors in a large container.
Cactus Identification: The spherical cactus has a hairy look with its distinctive globe-like form covered in delicate white fuzzy spines. The papery purple blooms that bloom on the flattened top of this globular cactus are another characteristic.
Balloon Cactus (Parodia magnifica)
The Balloon cactus, scientifically named Parodia magnifica, is a stunning spherical cactus with a vibrant yellow bloom. This beautiful cactus is ribbed, and its shape resembles a balloon, with rows of white or yellow spines running along the edge. Another noteworthy aspect of this cactus is the large yellow flower that appears on the top when it blooms. The Balloon Cactus can grow up to 6 inches (15 cm) tall and 18 inches (45 cm) wide.
Cactus Identification: The side of the spherical green plant of the Balloon cactus is dotted with distinguishable ridges. The cactus top blooms with a yellow flower, and each ridge has unique slender yellowish spines.
Christmas Cactus (Schlumbergera)
The Christmas cactus is a type of cactus native to the tropical regions of Brazil that blooms throughout the winter season. This cactus belongs to the Schlumbergera family, which includes several other cacti species. The Christmas cactus has long, flat segmented stems without leaves, and it is named for its winter blooming season.
The trailing flowering stems of the Christmas cactus make it ideal for hanging baskets or placing on top of furniture. This blooming cactus species produces flowers in white, pink, yellow, and red hues. Other related cactus species in the Schlumbergera genus include the Easter cactus (now classified as the Hatiora genus), Thanksgiving cactus, and Holiday cactus. These cacti bloom at different times of the year and have distinct species.
To ensure the Christmas cactus blooms, the flowers need to be kept in cool, dry conditions with 12-14 hours of darkness each day. The flattened rectangular green leaf-like stems with scalloped edges are the identifying feature of the Christmas cactus. The segmented succulent stems can grow up to 6 to 12 inches (15-30 cm) long and up to 24 inches (60 cm) wide. The shape of the leaves can be used to differentiate a Christmas cactus from an Easter or Thanksgiving cactus. The Easter cactus has rounded leaves with scalloped edges and soft hairs, while the leaves of the Thanksgiving cactus are flat with pointed or spiky edges.
Powder Puff Cactus (Mammillaria)
Mammillaria backebergiana ernestii (left) and Mammillaria boolii (right) are two cultivars of the Mammillaria family of cacti.
The Powder Puff cactus is a small, spherical cactus belonging to the Mammillaria genus of cacti. This slow-growing cactus species has delicate, hairy spines and a ball-like shape. It is one of the easiest cacti to care for within the Mammillaria family, growing to be about 3 inches (7.5 cm) tall and wide.
The Powder Puff cactus requires ample sunlight and should not be overwatered, like other cacti. Its crown of flowers typically blooms in the summer season. Other popular cacti from the Mammillaria genus include:
- Mammillaria backebergiana ernestii: A tall cylindrical cactus with a cylindrical shape.
- Mammillaria boolii: A small, spherical cactus covered in hair-like spines. The plant’s relatively large flowers are a notable feature.
- Mammillaria mystax: Indigenous to Mexico, this cactus produces red-violet flowers that bloom in April and May.
The Powder Puff cactus can be identified by its spherical, ball-like shape with clusters of pointed spines. While in bloom, this stunning plant produces a crown of purple, pink, or white flowers.
Moon Cactus (Gymnocalycium mihanovichii)
The Moon cactus is a vibrant variation of the typical cactus, with a top that comes in shades of red, pink, orange, or yellow, originating from Paraguay and Argentina. Moon cacti are cacti with ribbed stems that cannot produce chlorophyll, so they need to be grafted onto a succulent to grow. Moon cactus plants are typically sold already grafted, and they can resemble a flowering cactus atop a columnar succulent, which is their natural habitat.
These lovely cactus species are adorned with bright pink, orange, red, and yellow hues. Unlike other indoor cacti, these houseplants prefer partial shade. You should water the cactus thoroughly every time the soil dries out, and avoid watering or misting during the winter.
Cactus Identification: The bright ribbed ball sitting on top of a columnar three-sided cactus makes it easy to identify a moon cactus.
Chin Cactus (Gymnocalycium)
The Chin cactus, Gymnocalycium baldianum, is a tiny spherical indoor cactus that originates in South America. The chin cactus variety (Gymnocalycium) gets its name from the fact that it’s “hairless” or “spineless.” The Gymnocalycium genus has over 70 species, all of which produce vividly colored blooms. The smallest varieties of this cactus, which grow up to 6” (15 cm) in diameter, may be as small as 1.5” (4 cm).
Cactus Identification: The round form and huge colorful red, white, or pink blooms of Chin cacti varieties identify them. Some Chin cactus types have soft or sharp spines along the ridged borders, despite the fact that others are “spineless.”
Star Cactus (Astrophytum asterias)
The Star cactus, a tiny form of round cactus that some claim resembles a sea urchin, is native to Texas. It is a popular kind of indoor cactus plant. The Star cactus has a puffed-up spherical appearance with multiple divisions in its body. Rows of white dots with tiny hairs cover each of the segments. With a huge yellow bloom on top, the cactus should bloom in the spring.
Many cultivars have been developed since this type of cactus is a popular houseplant. The Astrophytum asterias ‘Super Kabuto,’ for example, is an attractive decorative cactus with patterns of fascinating white dots over the body.
Cactus Identification: The Star cactus has white dots, fine hairs, and a line of raised tufts along the center of each segment. It is a green cactus with a smooth round, bulging shape. In the spring, these non-prickly cactus flowers feature a pale yellow color.
Astrophytum asterias ‘Super Kabuto’
Fairy Castle Cactus (Acanthocereus Tetragonus)
The Fairy Castle Cactus is a tall, columnar cactus with long dark green angular spiny stems. It has new buds that look like castle turrets. Three to five ridges per cactus stem, each with six to eight 1.6” (4 cm) long spiky tufts, may be seen. Greenish-white blooms adorn the Fairy Castle cactus.
The curving stems of the main stems give the cactus its name, Fairy Castle or Fairytale Castle. The turrets of a castle are depicted as this characteristic. The Fairy Castle cactus is a popular decorative plant with its one-of-a-kind form.
Cactus identification: The lengthy green spiky stems, tiny side shoots on the stems, and pale orange blooms distinguish the Fairy Castle cactus. The cactus may reach a height of 6 feet (1.8 meters).
Lady Finger Cactus (Mammillaria elongata)
The Lady Finger cactus is a small cactus characterized by its stubby columnar stems covered in fuzzy, pointy spines. It is recognizable by its thick clusters of wooly, golden, cylindrical stalks, giving the cylindrical green stems a yellow or white appearance.
The Lady Finger cactus has upright stems that can grow up to 6 inches (15 cm) tall and 1.6 inches (4 cm) in diameter. As with all cactus plants, the Lady Finger cactus produces flowers on the upper sections of its stems. The petals of the flowers are light yellow or white and grow amid the hairy areoles. From late winter to early summer, the densely packed yellowish-green cactus blooms.
Cactus identification: The cylindrical stems of the Lady Finger cactus are woolly areoles with short yellowish spines in radial patterns, and pale-yellow blooms.
Feather Cactus (Mammillaria plumosa)
The Feather cactus has a rounded, woolly appearance resembling a fluffy ball of white cotton wool. The clumps of globular stems covered in a woolly, white, downy substance give the cactus its fuzzy appearance. Small pointed spines cover the blooming cactus, disguised by the soft feathery covering.
Each spherical cactus stem has a diameter of about 3 inches (7 centimeters). The plant is covered in a soft, feathery, downy substance and jagged spires, like many cacti in the Mammillaria genus. The Feather cactus blooms with flowers that have hints of pink and yellow.
Cactus identification: The cotton wool-like covering, spherical form, and spiky surface distinguish the feather cactus from other cacti.
Bishop’s Cap Cactus (Astrophytum myriostigma)
The Bishop’s Cap cactus is a spineless spherical cactus with three to seven vertical ribs and yellow or white blooms. It has a star-like appearance when viewed from above, and a bishop’s hat or miter-like shape from the side.
In the spring, the cactus produces yellow or white flowers. The Bishop’s Cap cactus is also known as the Bishop’s Hat or Bishop’s Miter cactus due to its grayish-green color. In the wild, the cactus can reach a height of up to 3 feet (1 meter) and a diameter of 8 inches (20 centimeters). However, as a houseplant, it remains a small star-shaped cactus due to its slow growth rate.
Cactus identification: The Bishop’s Cap cactus has a bluish-green or grayish-green color and appears like a bulging star with five pronounced vertical ribs.
Star Rock Cactus (Ariocarpus kotschoubeyanus)
The Ariocarpus kotschoubeyanus cactus, also called the “living rock cactus,” is a small, star-shaped cactus that features triangular stems forming a disc shape with a flat, woolly top and triangular tubercles around the border. It is notable for its vivid pink blooms that grow on top of the plant.
The diameter of this cactus species ranges from 3 to 7.5 cm, and its flowers can grow up to 1″ (2.5 cm) in diameter. The Ariocarpus kotschoubeyanus cactus gets its nickname from its gravel-like appearance.
Cactus identification: The cactus Star Rock is a disc-shaped plant with distinctive pointed triangular stems.
Crown Cactus (Rebutia marsoneri)
The Crown Cactus is a small spherical cactus with crimson, pink, yellow, or orange blooms and tiny rounded stalks that have a diameter of 3.5 inches (7.5 cm). The cactus is covered with soft, flexible light brown or white spines that form tufts. The globular cactus plant produces showy yellow, orange, pink, or red flowers from its base.
The Crown Cactus grows in clusters, with small cactus spheres developing into larger ones. It is one of the earliest cacti to bloom in the spring. Its scientific name is Rebutia minuscula.
Cactus identification: The spiny tufts that cover the bumpy surface of the Crown Cactus are small globe-like cactus with white or tan color.
Spiny Pincushion Cactus (Mammillaria spinosissima var. ‘Rubrispina’)
The Spiny Pincushion Cactus, scientifically known as Mammillaria spinosissima var. ‘Rubrispina’, is a cylindrical or spherical cactus covered in crimson spines. When grown outdoors, this cactus can reach a height of 12 inches (30 centimeters) and a diameter of 4 inches (10 centimeters). However, its growth is limited when grown in small pots indoors. During its flowering season, the Spiny Pincushion Cactus produces funnel-shaped pink blooms.
Cactus identification: The spiny pincushion cactus with bright red-orange spikes stands out against the green surface of this rough spherical cactus, which is known as the ‘Super Red.’
Eriosyce Cactus (Eriosyce senilis)
The Eriosyce cactus is a small, round, and fuzzy cactus that bears pink blooms. Its cylindrical shape is decorated with twisted, feathery spines, giving it a barrel-like appearance. The fuzzy top of the cactus produces bright pink blooms during its flowering season. These small and fuzzy cacti require small pots and prefer bright and dry environments with plenty of sunlight to flourish.
Cactus identification: The tiny spherical cactus is wrapped in woolly spines or hay, which makes it easy to distinguish from the Eriosyce cactus. Multi-colored spines adorn the cactus of certain Eriosyce cacti species.
Rat’s Tail Cactus (Aporocactus flagelliformis)
The Rat’s Tail Cactus, also known as the Whip Cactus, is an ideal succulent plant for hanging baskets due to its drooping cylindrical stems, which can reach up to 6.5 feet (2 meters). The slender tube-like stems are covered with tufts of tan spikes and fuzzy white hairs. The Rat’s Tail cactus produces bright scarlet pink funnel-shaped flowers when it blooms, making it a spectacular sight.
With its long, swinging succulent stems and colorful flowers, the Rat’s Tail Cactus is an attention-grabbing addition to any hanging basket. Its cascading tuberculate stems and vibrant flowers make it a popular choice for succulent enthusiasts.
Cactus identification: The 3 to 6 feet (1 – 2 m) long spiky tubular stems and beautiful floral exhibitions of brilliant pink blooms distinguish the Rat’s Tail Cactus.
Silver Ball Cactus (Notocactus scopa)
The Silver Ball Cactus is a stunning indoor plant with a fuzzy, rounded/cylindrical appearance. It features a wooly crown, yellowish-brown spines, and white tufts. The cactus can grow up to 20″ (50 cm) tall and 4″ (10 cm) wide. The bright yellow blooms with a crimson center at the top of the plant are a highlight. This cactus thrives in full sun and has long spines, making it an excellent addition to any houseplant collection.
Cactus identification: On this spherical green cactus with a yellowish, spiny look, the silver ball cactus is recognized by its yellow blooms.
Outdoor Types of Cactus (With Pictures and Names) – Identification Guide
Adding cactus plants to your garden landscape can be a great way to add unique texture and interest to your outdoor space. While cacti are known for their ability to tolerate tough conditions, it’s important to note that all cactus varieties require well-draining soil and should not be overwatered as this can lead to root rot.
If you have a small garden or balcony, there are plenty of small cactus species that are perfect for container gardening outdoors. Here are some popular outdoor cactus plants that you may want to consider:
Arizona Barrel Cactus (Ferocactus wislizeni)
Young Arizona barrel cactus with flowers on the right
The Sonoran Desert is home to two different cactus species, namely the Arizona Barrel cactus (left) and the Goliath Barrel cactus (right), that can be found outdoors. The Arizona Barrel cactus is a large, round cactus that can grow up to 6 feet (1.3 meters) tall and has a diameter of 2 feet (60 centimeters), while the most common varieties reach a height of 3 to 4 feet (0.9 to 1.2 meters).
The Arizona Barrel cactus has olive-green skin covered in yellow hooked spines on its ribs. It thrives in dry conditions and receives enough moisture from occasional floods. In mid-June, the Arizona Barrel cactus blooms with stunning crimson-orange flowers that can add a beautiful touch of color to any garden. Planted in a grid pattern, these cacti can create a striking feature in your outdoor space.
Cactus Identification: The Arizona Barrel cactus is a ball cactus with pointed spines and thick, leathery ridges. This spiky, spherical cactus has a cylindrical shape like many globe-shaped cacti. Its woolly top is ringed with colorful red or yellow blooms when it is in bloom during the spring or summer.
Prickly Pear Cactus (Opuntia)
Prickly Pear cacti, also known as Opuntia basilaris, are recognized by their purple or rose-colored blooms. This cactus variety is also called Beavertail cactus and is commonly found in the Sonoran Desert. The Prickly Pear cactus has large barbed spines, which can reach up to 1 inch (2.5 cm) in length.
The skin of this cactus is very delicate, and it can shed its spines, making it less desirable for gardens. The flattened pad-like structures of this cactus are blue-green in color.
Prickly Pear cacti come in different shapes and sizes, and they can be used for various purposes. For instance, the Beavertail cactus can grow into a shrub-like plant with pink flowers, while the tall Indian Fig cactus can reach up to 23 feet (7 meters) in height.
The Santa Rita prickly pear cactus is an excellent choice for chilly winters, growing up to 1.5 feet (45 cm) tall and tolerating temperatures as low as 15°F (-9°C). Identifying a Prickly Pear cactus is quite easy, as the large flat pads covered with long white spines are quite distinctive.
Saguaro Cactus
The Saguaro cactus is a tall and slow-growing desert plant that can reach up to 40 feet (12 meters) in height. It has the typical appearance of a cactus with a tall and slender central body that resembles a tree, and columnar arms. The Saguaro cactus is native to Mexico, Arizona, and California, and is a common sight in these areas. It has ribs with sharp spines that run up its length.
The Saguaro cactus is a flowering plant that blooms in late spring to early summer with white flowers. After the flowers have ripened, red and tasty fruits are produced. Although it can grow to be very large outdoors, the Saguaro cactus can also be grown indoors in a pot. However, it has a slow growth rate and can only grow up to an inch (2.5 cm) in height over a ten-year period.
Cactus Identification: The Saguaro cactus is easy to identify due to its columnar growth with arm-like structures. The spiky ribs of the vertical desert plant give it a ribbed appearance.
Queen of the Night (Epiphyllum oxypetalum)
Epiphyllum oxypetalum, also known as the Queen of the Night cactus or Dutchman’s Pipe cactus, is a flowering cactus that got its name because of its stunning white flowers that bloom only at night, making it an orchid cactus. This cactus is native to Southern Mexico and South America, and it has long ribbed cylindrical stems that can grow up to 20 feet (6 meters) in some cases.
The Queen of the Night cactus produces large white flowers that emit a sweet fragrance, which can be up to 11 inches (28 cm) long and 5 inches (13 cm) wide. The flowers bloom at night when the temperature drops between 52 and 57°F (11 and 14°C). This tropical cactus thrives in indirect sunlight during the day and is best grown as an indoor houseplant in colder regions.
Cactus Identification: The spectacular white blooms of the Queen of the Night bloom only once a year at night. Flat, long, trailing stems with wavy edges characterize the Queen of the Night cactus.
The Old Man Cactus (Cephalocereus senilis)
The Old Man Cactus, also known as Cephalocereus senilis, is a towering columnar cactus covered in a shaggy white coat. It’s an impressive addition to any garden with stems growing in clusters and reaching heights of 16 to 52 feet (5 to 15 meters). The Old Man cactus gets its name from its hairy appearance.
When grown outside, the Old Man cactus may take up to a decade to bloom. The blooms, which can be yellow, red, or white, will appear despite the cactus having lost some of its distinctive white shaggy coat. Sharp spines grow beneath the soft-looking hair of the tall cactus. The Old Man cactus prefers full sun and well-draining soil for optimal growth.
Cactus Identification: Because of its cylinder shape and white fuzzy appearance, the Old Man cactus is simple to identify.
Strawberry Cactus (Echinocereus enneacanthus)
The Strawberry cactus is a desert plant that loves hot and arid environments and blooms in a lovely magenta color. It is a type of blooming cactus that grows in clusters of small prickly stems, also known as Hedgehog cactus. Each cluster may have around 20 stems, and the plant blooms in late spring.
The funnel-shaped flowers of the Strawberry cactus have deep pink petals and a black and yellow center. These cactus blooms may grow up to 3.5 inches (9 cm) long. The sharp spines of this outdoor desert plant come in various colors, such as yellow, brown, white, and gray, and can add a unique touch to your garden.
Cactus Identification: The ribbed columnar spiky stems of the Strawberry cactus, as well as its magenta flowers and reddish-purple edible fruit, distinguish it as a desert plant.
Starfish Cactus (Stapelia grandiflora)
The Starfish plant is a unique succulent that produces striking star-shaped flowers. Despite its name, it is not actually a cactus. The plant has ribbed, green columns that can grow up to 12 inches (30 cm) tall. The star-shaped flowers, which can be up to 6 inches (15 cm) in diameter, come in various shades of orange, red, and purple.
The margins of the petals are dotted with white spots, and the flowers emit a strong carrion scent to attract pollinators. The Starfish plant is a popular houseplant due to its unique appearance and colorful blooms.
Cactus identification: The Starfish cactus is distinguished by its reddish-scarlet big star shaped bloom and tufted upright pale-green quadrangular stems with upward-pointing hooks on the borders.
Brazilian Prickly Pear (Brasiliopuntia brasiliensis)
The Brazilian Prickly Pear cactus is a type of cactus that is known for its succulent, juicy fruits that grow on the pads of the plant. This cactus species has a unique tree-like growth pattern with bright green, flattened stems that branch out from a central cylindrical stem.
It can grow up to 30 feet (9 meters) tall. The cactus pads have small spines that grow along the edges and the plant produces stunning golden to bright orange flowers that eventually turn into sweet, fragrant-smelling pear-shaped fruits.
Cactus identification: The slender, robust, rounded pole-like stem of the Brazilian Prickly Pear generates green oval, flattened spiny segments that appear like leaves.
San Pedro Cactus (Echinopsis pachanoi)
The San Pedro cactus is a tall and fast-growing cactus that has a pale green columnar stem with prominent vertical ridges. The stem is dotted with white areoles and spines. This cactus can grow up to 10-20 feet (3-6 meters) in height and 6 inches (15 cm) in diameter. It produces large, fragrant white blooms that open at night and can be up to 9 inches (23 cm) long.
The San Pedro cactus is a versatile plant that can be grown both indoors and outdoors, as long as it is in zones 8 through 10. The cactus stem has a star-shaped cross-section with rounded ends, making it easy to identify. The white areoles on the ridges are where the spines and small flowers grow.
Cactus identification: Ribbed columnar stems, jaggy spike tufts, and big fragrant white blooms identify the San Pedro cactus.
Walkingstick Cactus (Cylindropuntia spinosior)
The Walkingstick cactus, also called the cane cholla or spiny cholla, is a cactus with a fuzzy appearance due to its dense stem system that branches at right angles from the main stem.
It can grow up to 4 feet (1.2 meters) in height and produces purple-magenta blooms in the summer. Its fruit is spineless, yellow, and knobby.
Cactus identification: The Walkingstick cactus has branching stems that grow evenly at right angles and are 2 inches to 20 inches (5 to 50 cm) long.
Old Man of the Mountain Cactus (Oreocereus trollii)
The Old Man of the Mountain Cactus is a fuzzy, columnar succulent with long white hairs and stiff red spines. This slow-growing cactus grows in clumps in its native South America and thrives in indoor pots despite being a tall cactus.
The columnar cactus can grow up to 2 feet (0.6 meters) tall outdoors and is commonly referred to as the Old Man of the Andes. However, when grown in small pots indoors, its growth is limited.
Cactus identification: search for a columnar cactus with white woolly fur and long, dangerous red spurs to identify the Old Man of the Mountain.
Acanthocalycium
The Acanthocalycium genus, which is native to Argentina, includes numerous cactus species. These cacti have spiny floral tubes that give them their name, which is derived from the Greek words akantha and kalyx. The stems of Acanthocalycium cacti are either globose or elongated, and they have many ribs and spines.
Acharagma
The genus Acharagma contains two species from Coahuila and Nuevo Leon, Mexico. These plants have globose bodies that are no more than 3 inches in diameter and height. They may grow as individuals but put out multiple offsets from the bottom, and they might be somewhat cylindrical in shape.
They resemble Escobaria and Coryphantha in having tubercles and blooming from the apex, however they lack a groove from the areole to the axis. In Greek, the word Acharagma means “no groove.” [a (no) – charagma (groove)]. The sepals at least have a deeper vertical stripe, and the blooms are white to red to yellow. The stems are obscured by the spines, which are fewer than an inch in length and are quite thick. Smooth little green to purple colored fruits make up the fruit.
Arrojadoa
Species that develop in thin cylindrical stems branching from the bottom produce a Brazil-native ecosystem. One species’ stems may grow to be 3 inches thick, while the others’ stems are only 6 1/2 feet tall. The plant body is covered in close-set and prickly spines, with little ribs beneath.
As the stem continues to grow from the tip, leaving a collar of spines between the new and old segments, flowers emerge from the plant’s extremity each season, creating punctuated growth rings. The flowers are candy-like waxy tubes that last only one or two days and then turn black and fall off. They are vivid color -pink, red, white, or yellow. Little, nutritious berry fruits come in pink, purple, or red.
Austrocactus
Ten species of the genus Austrocactus are native to southern South America, Argentina and Chile. Except for Austrocactus spiniflorus, they have solitary or branching bodies and tubercules on their ribs (sometimes called knees). This genus’ tallest species is 80 centimeter tall. With a distinctive spiny tube, flowers are pink, orange, red, or yellow.
Austrocylindropuntia
The Austrocylindropuntia is a genus of shrubby cacti found in South America that is distinct from the Cylindropuntia genus due to its unique features. While both belong to the opuntiads and have glochids within the areoles, Austrocylindropuntia has round succulent leaves on new growth that fall off with age.
Additionally, their spines lack papery sheaths, and new stems and flower buds develop from areoles along existing stems. The stems do not have distinct segments between growth points. The flowers, which are yellow, orange, or red, grow on sturdy spiny floral tubes, and the fruits are spherical and thick. A. ceriferus is one of the most popular cultivars of the eleven species. In warmer climates, A. subulata and A. subulata clyndracea are sturdy, fast-growing plants that make excellent landscape plants.
Aztekium
Aztekium is a genus that came into existence after 60 years of separation between two species that belong to the same genus. These species thrive on gypsum cliffs, either vertical or close to it, and are found in separate populations in a single valley in the Mexican state of Nuevo Leon.
Because of their restricted range, they require strong protective measures to prevent them from going extinct in the wild due to illegal collecting. These cacti are extreme survivors and need protection to continue thriving.
Bergerocactus
Bergerocactus emoryi is a unique cactus species with distinctive golden spines that give it its common name, the Golden Snake Cactus. This plant is named after Alwin Berger and is the only species in the genus Bergerocactus. However, it is sometimes referred to as Snake Cactus, although that name is also used for the Echinocereus pensilis.
Blossfeldia
Blossfeldia is a small genus of cacti, with a single species that is considered to be the smallest of all cacti, growing to only half an inch (12 mm) in diameter. The species is named liliputana, a nod to the fictional island of Lilliput in Jonathan Swift’s novel “Gulliver’s Travels.” These cacti can grow either as solitary plants or in clusters with multiple stems. Unlike many other cacti, they lack ribs, tubercles, and spines. The tiny and delicate white flowers are smaller than the stem itself.
Browningia
These treelike cacti can reach heights of up to 33 feet (10m) and have shallow ribs, some of which may be tuberculate. Young growth of most species have spines, while older growth have minimal spines. The flowers of these cacti have large scales covering the floral tubes and come in white or red colors. Their fruits are small in size and typically scarce. These species are native to Bolivia, Chile, and Peru and are not commonly cultivated.
Carnegiea
The solitary species in this monotypic genus, Carnegiea gigantea (Saguaro cactus), is without a doubt the most commonly known and recognized cactus of all. In cartoons, post cards, book covers, paintings, and sculptures, the big Saguaro has represented the desert Southwest and has represented the west in general. As a result, many individuals believe that the tall, branching cacti in the west are connected to these quintessential cacti in the United States. This is in stark contrast to the popular image many people have of the Wild West, which is only found in central/southern Arizona and a little way into California on the Arizona border.
Cereus
In earlier taxonomy, Cereus was the name given to nearly all ribbed, columnar cactus species. However, over time, several species have been moved to different genera, leaving around 30 non-movement plant species in the Cereus group. The grouping has become jumbled and unsatisfactory due to the lack of exclusion rather than inclusion based on the genus description.
Cintia
Cintia knizei, a Bolivian alpine cactus, grows in the high Andes. In 1969, at an height of 4,000 m (13,000 ft) near Otavi in Potosí Province, Bolivia, Karel Kníže discovered the plant. Jan Říha, on the other hand, did not name it until 1996.
Cipocereus
Cipocereus is a group of short columnar plants native to Brazil, with distinguishing blue-colored fruits that contain watery pulp. The identification of these fruits has been crucial in establishing the genus, which was officially named in 1979 after its creator F. Previously, some of the species were classified under other genera. Over time, Ritter and other taxonomists transferred a few species from different locations, ultimately leading to the identification of a new species.
Cleistocactus
Cleistocactus is a cactus genus known for quantity as opposed to quality. Despite having numerous small features, this genus is still noteworthy. The stems are usually less than an inch in diameter, but they branch out easily from the base, creating conspicuous clusters. The spines are also tiny and pliable, yet often very abundant, sometimes even concealing the stems entirely.
The flowers of Cleistocactus follow the same pattern. Many species have blossoms resembling lipstick or fireworks tubes. The stems may be crowded with buds, which can bloom in dense clusters. With the right weather conditions, a plant may bloom every day of the year.
Coleocephalocereus
The genus Coleocephalocereus belongs to the Brazilian columnar cacti family Coleocephalocereus. The cephalium of these creatures grows wool and bristles. They may make up a dominating portion of the flora in these isolated, dome-shaped rocky outcrops, and they are widespread to the inselbergs of the Brazilian Atlantic rainforest.
Consolea
The Caribbean (including Florida, USA) has a tribe of Opuntiads called Consolea. They’re all little tree-like plants with cladodes (flat pads) that grow into round trunks as they mature. They grow to be about 20 feet tall. New cladodes appear at the end of these trunks, and they look like dandelions that have been tossed haphazardly around. This distinguishes the genus from other stemmed plants, including straight, circular, and unsegmented stems.
Copiapoa
Many cactus enthusiasts appreciate Copiapoa for its diverse range of species. Unlike some other cactus genera, such as Echinopsis which are known for their large flowers, Copiapoa species don’t have a particular defining characteristic. They are mostly globular or globular-cylindrical in shape, with distinct ribs and a woolly apex that produces mostly yellow flowers, like other members of the family. The funnel-shaped flowers, which typically range from 1 to 2 inches in diameter, have significant variations from one plant to another.
Coryphantha
The beehive cactus, known as the Coryphantha genus, consists of small, globe-shaped cacti with grooved tubercles rather than ribs. This genus is similar to Mammillaria and Escobaria. In fact, some Coryphantha species were once classified as Mammillaria but were later recognized as distinct. The main difference between Coryphantha and Mammillaria is that Coryphantha blooms from the first year of growth at the top of the plant, while Mammillaria blooms from second-year growth lower down on the stem.
Cumulopuntia
As more research is conducted on the Opuntiads, more species are being separated from the genus and placed in distinct genera. Backeberg, for example, classified several Opuntia species into the older genus of Tephrocactus in the 1950s. One of the first genera recognized as distinct from Opuntia was Cumulopuntia, which replaced F. with the name Ed Koch, in honor of the late mayor of New York City who died in 2006. Ritter combined species from Tephrocactus and Opuntia to create the new genus Cumulopuntia, with the key distinguishing feature being the lack of pulp in the fruit. Other Opuntiads have a unique seed structure and a compact cushion-like growth habit.
Cylindropuntia
The Cylindropuntia genus is not a commonly cultivated cactus, except for the enthusiasts of the Opuntia family. However, it is a well-known genus, commonly referred to as “Cholla,” despite not being widely cultivated. The Cholla is prolific and widely found in the deserts of Northern Mexico and the southwestern United States. The Cylindropuntia cactus typically has intertwining cylindrical stems that can reach up to 10 feet tall and resemble small trees.
Discocactus
Discocactus is a highly sought-after cactus genus among collectors worldwide, and there are several reasons for its popularity. The compact size of the plants, the striking white flowers, and the slow growth rate all contribute to their appeal. The stems of these cacti are usually flattened or globose and measure less than 10 inches (26 cm) in diameter. They have ribbed or tuberculate surfaces with fuzzy areoles or thick spines.
Echinocactus
The Echinocactus genus is relatively small, with only six known species. In the past, Echinocactus was a large genus that contained hundreds of species due to the use of a few names that covered a wide range of cacti with similar characteristics. This included ribbed, barrel-shaped plants that were not yet classified as Cereus or Melocactus.
Echinocereus
The cactus genus Echinocereus is beloved by plant enthusiasts worldwide for a variety of reasons. For starters, all Echinocereus species are small, making them ideal for indoor cultivation in pots or greenhouses. Their stems typically measure less than a foot in length and range from two to three inches in diameter, although some species can be larger or smaller. While some Echinocereus species can grow into massive mounds of hundreds of stems in the wild, cultivation allows for easy management of their size and shape.
Echinomastus
Echinomastus is a genus of small, elongated, globular cacti found in the Southwestern United States and parts of Mexico. There are between 5-9 species in this genus, with stems that typically reach a maximum height of 12 inches and seldom branch. The stems are heavily covered in spines that arise from tubercles arranged in rows with areoles on them. The tubercles have a groove and there may be additional nectaries nearby, making these plants quite unique.
Epiphyllum
Epiphyllum is a group of 19 species of epiphytic cacti native to Central America. They are also called climbing cacti, orchid cacti, and leaf cacti, and were previously classified under the genus Pereskia.
Epithelantha
The Epithelantha genus comprises only two species of small cacti. Although several species have been identified based on differences in spination, the majority have settled on the two main species, with variations classified as subspecies. Taxonomists and cactus enthusiasts seem to be content with this classification. Both species are small, with stems barely exceeding 2 inches (5 cm) in diameter and height. The white spines emerge from tubercles, similar to Mammillaria, and vary in length.
Escobaria
The Escobaria genus comprises small, globular to cylindrical cacti that grow in clusters or individually. They have tubercles and are part of the Escobaria genus, while many species were previously classified as Coryphantha and Mammillaria. The plants’ general appearance, particularly the presence of tubercles, led to their inclusion in Mammillaria, but unlike Mammillaria, the areoles of Escobaria do not have separate areas for producing spines and blooms from fresh growth at the summit.
Espostoa
The Espostoa genus comprises approximately a dozen species that are found in Ecuador, Peru, and Bolivia. These columnar plants have stems that form a chain and their base branches out, creating the appearance of a large city skyline. The most notable feature of Espostoa is its thick, white hair that covers the branches entirely, providing them with a delicate, fuzzy look. This soft hair is actually an illusion and is covered with numerous sharp spines that encircle the columns. In reality, the soft hair is covered with tiny ribs. Some species have a main central spine that extends well beyond the hair, giving them a menacing appearance.
Espostoopsis
The genus Espostoopsis is closely related to the Espostoa genus, as indicated by its name. Despite having few apparent differences with the lone species of Espostoa, Espostoopsis is distributed globally. Taxonomists have not classified this species as part of Espostoa, according to further studies. Initially, it was recognized as an independent species in both Austrocephalocereus and Coleocephalocereus, but in 1968, it was assigned its own name.
How to Grow Cacti Plants Indoors
Caring for indoor cactus varieties is surprisingly easy, with many suitable species available at garden centers and retailers. To ensure optimal growth, it is best to place your cactus in a sunny window sill in the southern hemisphere. One of the most important things to remember when growing indoor cactus plants is to water them carefully.
During the growing season, when it is particularly bright, cacti generally only need to be watered regularly. It is important to water them thoroughly but allow excess water to drain through the holes in the pot.
In the fall and winter, indoor cacti only require light watering every few weeks. Cacti prefer temperatures of 70°F to 75°F (21°C to 23°C) during the day and 60°F (15.5°C) at night throughout the growing season. When potting indoor cacti, it is best to use cactus-specific soil and fertilizer.
How to Care for Outdoor Cactus Types
Cacti are great additions to various types of gardens, especially those that receive ample sunlight and heat during the summer months. Depending on where you live, there may be cactus plants that can withstand freezing temperatures during winter.
When choosing a location to place your outdoor cactus, it’s important to select a spot where water can easily drain. For example, placing the cactus on the top of a rock garden or on a south-facing slope will prevent waterlogging.