Part 1: A Beginner’s Guide to Cannabis-Plant Classification

hemp marijuana classification

Part 1: A Beginner’s Guide to Cannabis-Plant Classification

To help humans make sense of things, we like to classify them into groups and give them labels. We need to classify cannabis plants so we can determine the best use for each plant variety. But classifying cannabis plants has become a very confusing subject, clouded by legal, financial, political, and scientific arguments. In this beginner’s guide to cannabis-plant classification, we give you enough basic knowledge to understand how cannabis plants can be classified and thus the knowledge to determine what is best for your needs.

“No other species has generated so much misunderstanding, argument, and contradictory literature.”

Dr Ernest Small

What is cannabis?

Cannabis is a plant species. Non-botanists like us would call it a flowering herb. Other flowering herbs you would be familiar with include thyme, oregano, sage, and rosemary.

Four uses of the cannabis plant

In his 2017 book—Cannabis: A Complete Guide—Canadian research scientist, Dr Ernest Small, simplified cannabis into four main plant uses. These are:

  1. Wild-growing weeds (wild)
  2. Plants used for stem fibre (domesticated)
  3. Plants used for edible seeds and hemp-seed oil (domesticated)
  4. Plants used for medical purposes and getting high (domesticated)

Current ways of classifying cannabis

The bottom line is that cannabis-plant classification is as confusing as hell. There are several ways experts, self-proclaimed experts, and lay people may choose to classify cannabis plants. These include:

  • plant taxonomy
  • genetics
  • appearance
  • cannabinoid and terpene profile
  • legal status

Classifying cannabis using plant taxonomy

Plant taxonomy was the original method botanists used to classify the cannabis plant. This method is contentious amongst experts when you get to the species and subspecies levels of cannabis. Legal implications have muddied the waters considerably.

Dr Small’s simplified taxonomy classification

A cannabis classification system which divides cannabis into six cultivar groups—first proposed by Dr Ernest Small in 2015—is becoming widely accepted as the most common-sense taxonomy classification system to date. Dr Small’s research recognises only one species of cannabis, i.e. Cannabis sativa (C. sativa), with six main varieties. (Read more in Part 2.)

Classifying cannabis plants using genetics

With access to advanced genetic technology—like genome sequencing—we are now moving away from the inexact science of plant taxonomy and using the genetic profile of cannabis plants to work out what they are and, more importantly, what they are best used for.

Classifying cannabis plants based on appearance

Plant appearance is where the indica vs sativa experts like to weigh in. Self-proclaimed “experts” describe sativa as tall and woody and indica as short and bushy. You might be forgiven for thinking that these “experts” know whether a plant is high THC, low CBD, and so on, just by looking at it. Unfortunately—due to the significant amount of hybrids and selective breeding that goes on with cannabis plants—a classification system based on appearance alone is not very helpful.

Indica (marijuana)

Cannabis indica is used to describe cannabis that is high in psychoactive THC. Diehards will tell you that indicas are sedating and relaxing in their effects. Marijuana is said to fall into the indica category.

Sativa (hemp)

Cannabis sativa is often used to refer to cannabis that is low in psychoactive THC. Die hards will tell you that sativas are uplifting and invigorating in their effects. Hemp is said to fall into the sativa category.

Classifying cannabis plants based on cannabinoid and terpene profile

Some experts will determine how a plant should be classified—and thus what it is best used for—by establishing its cannabinoid and terpene profile. i.e. which cannabinoids and terpenes are found in the plant and in what quantities? For example, is the plant balanced (e.g. 10% CBD and 10% THC), is it low CBD and high THC, is it high CBD and low THC, or is it predominantly other cannabinoids like CBG? Israel’s Dr David Meiri’s lab has produced extensive databases on cannabinoid and terpene profiles of different cannabis varieties. Even the soil or location it is grown in can affect the profile, as Dr David Meiri’s research has shown.

Classifying cannabis plants based on legality

Legal implications is where the ‘hemp’ vs ‘marijuana’ arguments arise.


The United States waged a successful scare campaign against cannabis in the 1930s and enshrined it in legislation.

Because of this, all cannabis was lumped into a basket with other illicit drugs like heroin and became highly illegal to use or possess. It became known pejoratively as ‘marijuana’.

Boom. Fast forward 80 years. That’s why cannabis is illegal. That’s why we think politicians are gormless fools. That’s why many doctors are wilfully ignorant. And that’s why patients who need or want any kind of cannabis in Australia are in a big fat mess now.


Hemp is often used to describe cannabis varieties that are lower in CBD. It is also often associated with cannabis varieties that are grown for their fibre, and you may hear it called ‘industrial hemp’. However, it’s really important to understand that some of the world’s highest quality, organically-grown CBD oil comes from these very same cannabis varieties that are high in CBD and low in THC.

The ‘marijuana’ legislation also caused problems for farmers who grow non-psychoactive cannabis (or hemp). So the powers that be came up with legislation to get around it, whereby some very-low-THC cannabis plants do not fall into the highly illegal basket. The allowable levels of THC vary around the world, but it’s usually around the 0.3% or 0.2% mark (more on that in Part 2).

Now you know how to classify cannabis

Now that you know the basics of cannabis classification, and why some of these terms and methods persist, you can use this information to make better decisions about the cannabis varieties that best suit you and your family’s needs.

Part 2 of cannabis-plant classification

Join us for Part 2, where we discuss cannabis-plant classification in more depth.

We’ll help you understand why some classification systems stand out over others as the way of the future for using cannabis for health, wellness, and medicine.

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