You've got a new cactus plant (or maybe a few of them). Now you are looking for a name. You may already know that task is easier said than done. This site exists to ease your cactus identification pain! Since even
the most common cacti are often sold without names, new cactus owners are often left hunting for a name with few places to turn. This page is designed to speed up ID on the cacti that are most common and that
is why this is the perfect place for you to start!
Cereus Peruvianus -The Least and Best Known Cactus
As the owner/creator of a website dedicated to the identification of Cacti, I run into lots of people who ask for my help identifying a particular cactus plant. Often times the mystery plant is not a cactus at all, such as an Agave or Euphorbia, but that's a subject worthy of its own article. This article is written to address a particular cactus plant that is simultaneously one of best known and least known species in the entire cactus family. It is Cereus peruvianus. This plant or rather the identification of it is the cause for a great deal of confusion. The source of this confusion is multi-faceted and this article will examine those reasons.
To start with, whenever you run into the name "Cereus", there's a good chance you are dealing with a plant that has not received much attention by those who scientifically study and classify cacti. Most experts agree that cereus is
one of the least understood genera of the entire Cactus Family. It is also one of the oldest names in the family, described by Philip Miller in 17541 it dates back to 1625. From the beginning up until the 1920's, nearly every
columnar cactus was given the name cereus. Today there are 34 species that are officially accepted to belong to the genus
Cereus, but there are over 500 species or synonyms that were once classified under
Cereus that are now either no longer accepted or have been reclassified as a separate genus. The name
Cereus peruvianus has been applied to both
C. hildmannianus and
C. repandus which are both recognized as legitimate species today. The trouble is, neither of them resemble the many plants that we see labeled as
Cereus peruvianus. Therefore the logical conclusion would be that these plants are simply not properly identified and through due diligence, we should be able to find their true name. Yet what we find is that the best choice
of names turns out to be
Cereus peruvianus! Sound absurd? That's because it is.
Etymology: From the Greek words gymnos, meaning naked and kalyx, meaning bud. Mihanovichii. Named after M. Mihanovich. I am not certain about the cultivar name ‘Hibotan’ Origin: This is a man made cultivar, mainly produced in Japan
and Malaysia Light: The plant likes good light, but not particularly fierce sunshine. Compost: Any normal open cactus compost will suit this plant Water: Will take normal watering during the summer. Flower: The flower is a pinkish
colour. The flowers usually appear around mid summer and are typical of the genus. It is one of the few plants with no chlorophyll that actually flowers, as far as I know.
Fruit: Min. temp: The plant is almost always grafted on to a non hardy stock. It would be impossible for me to say which one as they vary. But because they are non hardy stocks the plant will need to be kept at a temperature of at least 45°f. (10°c). Cultivation: Not a difficult plant to keep, although they are not particularly long lived in cacti terms. I don’t know why they are always produced on such long root stocks. I always reduce mine by half so that the plant at least looks as though it is on its own roots. If you are familiar with grafting, the plant would perhaps be better on a Trichocereus. Habitat: A Japanese nursery bench Comments: This is not really a plant for the ‘purist’ but at the risk of upsetting some members who probably think that it should not be in this section. We get so many new members or members who have few plants, writing in to say “I have got a round cactus that is all red and looks like a lollipop.” Well now hopefully they can be referred to this page and their curiosity will be resolved. All things considered they are not a bad looking plant. The one in the photograph is mine and I am not ashamed to admit that I have a couple of others of varying colours.
Growth Habits: This Opuntia has the growth characteristics of most of the genus, but tends to grow more upright than many of them. In habitat or open ground it can achieve a height of 3ft. and a spread of 6ft. The cladodes (pads) are usually slightly longer (usually up to 4in. [10cm]) than they are wide and they are spineless, but don’t be fooled by this, they have tufts of thousands of barbed glochids which can attach themselves to the unwary at the slightest touch and are annoying and irritating, rather than painful. There are a number of varieties, rufida has reddish glochids, albata has white and is perhaps the smallest variety usually only growing to 18in tall. It is also the one that is most likely to flower when pot grown. There is also a monstrose variety. The plant can be grown from seed, but in practical terms is almost always propagated from cuttings of the pads (which should be at least one year old).
Scientific name: Opuntia microdasys Synonyms: Bunny Ears, Polka Dot Cactus. The monstrose variety is sometimes called Funny Bunny. Etymology: The generic name "Opuntia" refers to a Greek name used by Pliny for a diverse plant which grew in the region of the town of Opus in Greece. Microdasys: From the Greek mikros, small, and dasus, hairy. Origin: Mexico (Hidalgo) Light: This plant will take all the sun you can give it, but will also grow well in light shade. Compost: Your normal compost mix will suit this plant fine. If you are known to be heavy handed with the watering can, mix in a little more grit. Water: Once the plant is established in open ground it does not need a great deal of water. If it is kept in a pot, water slightly less than normal. Nevertheless give it a good soak and then allow to dry completely before watering again. Do not water little and often which is a recipe for disaster.
Flower: The flower can vary from yellow towards orange and is not often seen on plants in pots, but they do appear in profusion on plants in open ground. The fruit is round and reddish in colour. Min. temp: It can stand 20°f.
(-7°c) for a brief period, but may shed some of its pads. A more reasonable minimum temperature would be about 45°f. (8°c.) Cultivation: This plant is quite easy to keep. As has been said above a normal compost is quite
adequate with not too much fertiliser (this would tend to make the plant grow unnaturally). One of the beauties of this plant is that you can train it to the shape you would like it to be by removing pads that are surplus
to requirements, a little like training a bonsai tree. If the plant is desperate for water (unlikely), the top pads will start to droop, but will soon become erect again after watering.
The plants we see carelessly tossed into the classification of Cereus peruvianus are all very easy to grow. They tolerate a wide variety of conditions, they can be propagated easily by seed and even more easily by cuttings. They are resistant (indeed impervious) to rot, disease, and infestations; they grow fast and they produce nice large white flowers without any coaxing. You will find these plants in cultivation across the globe. They are in just about every garden center that sells cacti and they are inexpensive. In warmer areas they can be planted in the ground where they obtain massive size over 20 feet high with many branching arms. These qualities make the problem worse as their popularity keeps them spreading around the globe. They show up in the collections of the novice or slightly interested cacti growers, who sometimes are inspired to search for a name for their cactus. What do they find? Cereus peruvianus! This brings us full-circle. Perhaps someday the right biology student will decide to do a thesis on the "Origins of Cereus" and we'll all get lucky. In the mean time you can probably get away with using the name Cereus peruvianus as everyone will have a good idea of exactly what plant you have based on that name. And if that is the purpose of a name, then Cereus peruvianus fits the bill.