Purple cannabis varieties: what causes their colouring?

• Why are some cannabis varieties purple?
• Anthocyanins or natural dyes in action
• How do anthocyanins work?
• What role do genetics and environment play?
• Soil
• Heat
• Light
• Purple Haze
• Purple Queen
• Blueberry
• Car Blackberry Kush
• Purple Kush
• Purplematic CBD
• Conclusion

Why are some cannabis varieties purple?

While most cannabis varieties are green in colour, there are a few exceptional ones that boast a unique purple colouration. And not only are they visually appealing, they have other interesting characteristics. 

The secret of purple varieties lies in substances called anthocyanins. Plants high in anthocyanins are more likely to acquire the colour, and some cannabis varieties are inherently richer in anthocyanins due to genetic predisposition.

Anthocyanins or natural dyes in action

But what exactly are anthocyanins? Don't worry, there's no complicated biology lecture waiting for you. Simply put, anthocyanins are natural dyes that are flavonoids - organic compounds present in plants. They are soluble in water and cause purple, blue or red hues in flowers, fruits and sometimes even leaves. The most common type of anthocyanin in plants is cyanidin, which together with delphinidin produces intense red and purple colours.

Anthocyanins can be found not only in cannabis, but also in other plants such as blueberries, red cabbage and aubergines.

To make matters worse, anthocyanins also play a crucial role in the change of leaf colour in autumn. Thanks to them, we can enjoy beautiful shades of red, purple and gold during the colder months.

How do anthocyanins work?

Anthocyanins perform two essential functions in terms of plant physiology:

• Pollination: anthocyanins help attract pollinators such as bees, butterflies, or hummingbirds, while also deterring some insects by giving the impression that the plant is not in an ideal state for consumption.
• Protection: thanks to their antioxidant properties, they provide the plant with protection against extreme light conditions, thus contributing to its resilience.

What role do genetics and environment play?

Many cannabis varieties, whose names often include a reference to colours, have a genetic predisposition to higher levels of anthocyanins. But genetics is not omnipotent - it alone does not guarantee distinctive purple hues. Rather, these varieties have the potential to show colour when exposed to the right conditions.

In other words, the purple colour of cannabis is caused by a combination of genetic and environmental factors that promote anthocyanin production. Although research on anthocyanin production in cannabis is not yet extensive, scientists are drawing on numerous studies carried out on other plants.

Let's take a look together at the key factors that influence whether cannabis turns purple.

Soil

According to a study published in the Pakistan Journal of Nutrition in 2006, anthocyanins in plants tend to degrade at higher pH levels, meaning that purple hues are most common in soil with neutral or slightly acidic pH.

For the sake of interest, let's see how the other colours are doing:

Temperature

Purple colouration (but also other colour variations) is often affected by lower temperatures. Cold can slow or temporarily stop the production of chlorophyll, the green pigment in plants. This process is familiar, for example, from autumn leaf colouration. It is therefore not surprising that many purple varieties of cannabis come from colder regions, such as the Hindu Kush mountain belt in Afghanistan and Pakistan.

Light

More intense light increases the concentration of anthocyanins, and blue and UV light are the most supportive. UV light activates plant defence mechanisms, leading to the production of anthocyanins, which protect cells from damage and act as antioxidants.

There are a huge number of cannabis varieties with stunning purple hues. We've selected a few of the most interesting ones that will impress you not only with their appearance, but also with their genetics, origin and aroma. 

Purple Haze

Inspired by Jimi Hendrix's iconic 1967 song, Purple Haze is a sativa-dominant variety that entices with its purple colour and sweetly spicy aroma. This hybrid comes from Colombia and combines sativa and indica genetics. It is most often combined with Haze and Purple Thai.

Purple Haze is recognisable by its enchanting purple flowers, which shine in all shades of purple - from deep rich to soft purple. And the scent? Bold, earthy, yet sweetly spicy. Some say they also smell flowers, woods, or even a light whiff of citrus when they sniff it. 

Purple Queen

Purple Queen is literally the crowned queen of purple varieties, which is confirmed not only by its name, but also by its vibrant purple palette and intense aroma, which mixes pine and petrol notes. This pure indica was created as a combination of Hindu Kush and Purple Afghan genetics - Hindu Kush gave it its hardiness, while Purple Afghan added its beautiful purple colour and pleasant aroma.

Purple Queen is one of the modern varieties that have gained popularity thanks to breeding programmes in the Netherlands and Spain, where cannabis culture has strong roots.

Blueberry

Blueberry, a legendary indica-dominant strain, earned first place in the Best Indica category at the 2000 High Times Cannabis Cup. Its story dates back to the 1970s, when Canadian grower DJ Short experimented with genetics from three continents:

• Afghani: Afghan indica, forms the main basis of the variety
•  Thai: Thai sativa, strongly influences genetics
•  Purple Thai: Mexican variety from the Oaxaca region, smaller genetic proportion

The resulting jewel was later entrusted by the grower to the Dutch Passion seed bank, which introduced it to the European market in the late 1990s. This genetics later became the basis for many modern varieties such as Blue Dream and Blueberry Headband.

Blueberry flowers are blue-purple in colour and have a distinct sweet scent, reminiscent of fresh blueberries.

Car Blackberry Kush

Among the autoflowering varieties, the Auto Blackberry Kush, which was developed in the Netherlands by Dutch Passion and combines Blueberry and Dark Kush genes, deserves special attention.

This indica-dominant hybrid variety has a unique aroma that combines the sweet, fruity notes characteristic of the Blueberry genetics with the smooth, earthy base inherited from the Kush line.

Moreover, the Blackberry Kush car turns into a real visual treat when harvested - its leaves and flowers play with every shade from deep purple to almost black. And that's not all, this plant grows pretty vigorously, and it also forms lots of side branches.

Purple Kush

Purple Kush, bred in Oakland, California, is a pure indica that perfectly combines the best of its parent varieties: the Hindu Kush and Purple Afghani.

Hindu Kush is native to the rugged mountains on the border of Afghanistan and Pakistan and is known for its resilience to harsh conditions. Purple Afghani, on the other hand, brings unique purple notes and a pleasant, sweet aroma to the mix.

Purple Kush smells of earthy woods and fresh earth, complemented by sweet notes of grapes and berries. Its appearance is equally striking - rich green foliage contrasts with deep purple flowers that resemble a bush covered in fruit.

Purplematic CBD

Purplematic CBD is a carefully bred strain that was created by crossing Kush Rose Auto CBD and Afghan Rose Auto CBD. This combination makes it one of the autoflowering genetics with an extremely high CBD content of up to 17%.

The THC content remains extremely low at less than 0,5 %. This stable hybrid has a predominantly indica genetic make-up (90 %), supplemented by sativa and ruderalis in a proportion of approximately 5 %.

Purplematic CBD stands out for its rich and complex aromatic profile, which is due to the diverse representation of terpenes present in the plant.

The main terpenes include:

• Limonene - citrus freshness
•  Myrcene - herbal notes with a hint of clove
• Terpinolene - floral and fruity undertones
• Caryophyllene - peppery and woody aroma
• Pinen - a touch of pine

This variety also immediately catches the eye with its appearance, especially the unusually large pistils, which contrast strongly with the rich purple flowers.

Conclusion

The unique purple colouring of some cannabis varieties is due to anthocyanins - natural dyes that perform not only an aesthetic but also a protective function in plants. In addition to genetics, the environment plays an important role, especially temperature, soil pH and light intensity, which can increase the production of anthocyanins and promote the distinctive colour tones. The most interesting purple cannabis varieties include Purple Haze, Purple Queen, Blueberry, Auto Blackberry Kush, Purple Kush and Purplematic CBD.

Autor: Pavla Skřivánková 

Photo: AI

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