It's not the first colour you think of when you think about flowers is it?

Black flowers are arresting, eye catching and beautiful. Other flowers just have to make do with 'pretty'!

Look Stunning in Black

Black’s sexy, sassy and everyone looks cool in it, including flowers. 'Black' flowers are not only exclusive they’re elusive.

Look deep into those black petals and you’ll see tones of purples, blues and reds. Just like black printer ink, which is a combination of purple, blue, red and yellow, black flowers contain a combination of coloured pigments.

In fact a truly black flower is harder to find than true love, it doesn’t exist.

Though with over 2750 varieties of dark plants, some do have flowers that come deceptively close to black.

How Do Flowers Look Black?

A flower looks black because pigments in the petals absorb red, green, yellow and blue light. With all the light being absorbed none is reflected back off the petals so they appear black.

Carotenoids are pigments that give red, orange and yellow colouration, while anthocyanins are responsible for blue, red and purple colours. Pigments need sunlight and most black plants being highly pigmented grow best in direct sunlight. But beware there are a few that fade in full sun.

Black in Nature

If you see any hints of colour when you look at a flower or leaf then, it’s not black.

Most flowers are bright colours to attract insects. Even the ones that attract flies are meat-red and smelling of rotten flesh. They’re not rotten - if they were they might be black.

The nearest any flower will get to being black is when cell death occurs.

There are naturally occurring flowers that come very close like Lisianthus nigrescens that grows in southern Mexico and Guatemala. To insects some black flowers won’t look black.

The flowers have markings that can be seen by an insect’s eye or under ultraviolet light. These markings are thought to guide the insect to the nectar.

Apart from the odd ‘lucky’ mutation most of the black flowers we grow were created by years of painstaking artificial selection of darker and darker petals. Because black plants and flowers make such striking ornamental plants if you managed to make one it would prove exceedingly profitable.

Petal colours

A petal’s colour depends on the pigments it contains. There will normally be several different pigments.

These can be separated by chromatography. This is where a solvent moving through a strip of filter paper carries dissolved pigments upwards. Pigments become separated because they move at different rates.

Chromatography depends on dissolving pigments and some are fat-soluble, others water-soluble.

If you want to see the whole range of pigments in a petal you may have to do chromatography using a fat solvent like acetone (nail varnish remover) and a separate one with water.

You don't need a black flower for this, any darker flower will have a combination of pigments.

What you need

• Solvents - Acetone (nail varnish remover – it's strong stuff, always keep it away from your face, particularly eyes and mouth) and water

• Coloured petals

• Coin or pestle and mortar (do not use one from the kitchen petals may contain poisons)

• Plastic cup (check the acetone doesn't dissolve the plastic, use a glass or jam jar if you're worried)

• A Ruler

What to do

1. Cut the filter paper into strips about 2cm by 6cm.

2. Mash the petals with the pestle and mortar. Place a spot of the petal juice onto the filter paper about 2cm from the bottom.

3. Alternatively place the petal onto the bottom the strip of filter paper. Then roll a coin firmly over the petal, about 2cm from the bottom, leaving a line of petal juice across the strip of paper.

4. Pour solvent into the cup/jar to a height of 1cm.

5. Place the bottom of the strip of filter paper into the solvent so the petal juice is above the level of the solvent. Fold the top end of the strip and hook it over the cup rim so the paper does not fall in. As the solvent moves up it will take the petal juice with it separating the pigments.

What’s happening?

The pigments that are soluble in the chosen solvent will move up the filter paper with the solvent. Because different pigments don’t all move at the same rate they become separated. Some pigments are soluble in water others are fat-soluble (dissolve in acetone). What pigments are present in the petals? The table below will help you identify them.