The Undervalued Link Between Colour and Scent

My nose tells me that there must be a genetic link between flower colour and flower scent, but it’s not something written about at all in the garden literature.  Maybe I’d find something in the literature pertaining to breeding for the florist industry, but I don’t know where to look.

As a brand new gardener, aged 17, I made a really dodgy rose garden at my Mum’s place.  I did everything wrong, as you do when you’re starting out.  It’s more than just fortunate that all the mistakes don’t really get in the way of your pleasure.  One of the great things about gardening is that it’s as much fun and just as rewarding when you start out as it is, years later, when you start to know what you’re doing.

This is not my dodgy rose garden.  This is the rather more successful one on Isola Bella, Italy.  The red and pink alternation is, however, dodgy, though there's no faulting the gardeners skill in growing them, tying them in, etc.  If you could actually walk this path (it was roped off), you'd likely experience an alternation of perfumes along with the colours...
This is not my dodgy rose garden. This is the rather more successful one on Isola Bella, Italy. The red and pink alternation is, however, dodgy, though there’s no faulting the gardeners skill in growing them, tying them in, etc. If you could actually walk this path (it was roped off), you’d likely experience an alternation of perfumes along with the colours…

That aside, one of the mistakes I made in this circle of a dozen roses, was to choose a dozen different roses.  One of the nice consequences of the mistake was that I quickly came to suspect, and later confirmed (though again only via an accumulation of personal experience), that rose scents are very strongly attached to their colour.  By 19 or 20, I reckoned that, under a blind test, I could guess the colour of any rose by its scent alone.

The pink ones are the most ‘rosey’ – that rose scent like that of rose oil, or rose water, that translates to the flavor of Turkish Delight.  The scent of red roses is altogether deeper, in perfect correspondence with the relative darkness of the blooms.  And the perfumes of autumn-toned roses (my favourite in this group of plants, for which I can’t, even at best, conjure more than mild affection) are sweeter than all the rest, totally distinct, and immediately recognizable.

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Leap, then, to polyanthus.  None of these carry a scent except the yellow tones.  For this reason alone I’ll choose them over all other colours, which feel one-dimensional in comparison.  It is surely no coincidence that the yellows are closest to the wild – and scented – primroses (Primula vulgaris), and perhaps to the cowslip (Primula veris), also scented, though I’m not sure whether the latter contributed to the parentage of polyanthus.

I recently wrote on my Facebook page about the stunning scent of Cyclamen purpurascens (top image – which I argued was possibly the most sophisticated of all flower scents.  You can access the argument by clicking here, and then scroll down to March 12), and then bought a bog-standard miniature pink florist’s cyclamen the other day (below) and was stunned at the perfume.  I assume that this is, like the polyanthus, because it’s genetically closer to the scented species Cyclamen persicum from which it is derived, than the other colours such as white and deep red, which have no scent at all.

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And thence to petunias.  You can sneer at them, but there’s no denying the appeal of their evening scent, while you’re watering.  I confess I severely underestimated them until I read Christopher Lloyd mention their close genetic relationship with the deliciously perfumed, and altogether more refined Nicotiana.  This had never occurred to me before, and had the effect of immediately reducing my prejudice.  They went up in my estimation due to the family association (I should add that I’m not proud of the obvious snobbery, but neither will I deny it), and I’ve been loving them (with only a few remaining reservations) ever since.  In perhaps no other commonly grown flower is the association of potency of colour and scent better illustrated.  When it comes to petunias, the deeper the colour, the richer the perfume.  The deep purples are the best of all, and totally intoxicating – almost dizzying – after sunset.

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Discussion

  1. How good is it that, as a passionate amateur, we occasionally read deeper contemplations on what often are passing thoughts in our busy heads? Thanks so much for your blog! There’s been so many times I’ve wondered if there was a connection between the blue/lavender colour of roses and that unique perfume that many of them have – particularly Blue Moon. I really can’t bring myself to put it in my garden – just wouldn’t work here at all; but there’s been so many times when I’ve walked past a bush of a similar colour and recognised the scent. Every spring I’m torn with the choice of white or purple petunias in the big pots by the back door; white looks so much better, but the purple incense floats through the place in the evenings.

    1. Let me tell you, passionate amateurs have all the best thoughts passing through their heads. The disillusionment regarding my naive conviction that the professionals must have still deeper, richer, better thoughts nearly drove me out of gardening 30 years back…

      And I face the same dilemma re: white or purple petunias. It’s a bit sad really, given that we should be troubling over much, much more interesting plants for pots. But such are the offerings of the garden centres, and I’m yet to master the overwintering of cuttings of the tender stuff I’d like to grow in pots, but can’t access when I want them in late spring.

  2. I expect the scents made more sense to insects and other pollinators before we humans started tinkering with flower shapes and colours.
    Now the poor purple petunia can’t even remember its matching moth and has to lure the less snobbish gardeners to hardware stores with promises of exotic evenings by the hills hoist.

    1. I reckon I’ve got about a week of those memorable evenings by the Hills hoist, before frost poops this Indian-summer party.

  3. Hello Michael,
    I’m a dodgy rose grower of the first order and to me the sweetest are the reds, purples and pinks while the orange/yellow blends often have that fruity or bitter green ‘tea’ scent that kind of smells like tomato leaf to me.

    There’s also a huge variation between certain individual roses in the same colour group depending on the type of rose. E.g. a pink early tea might smell similar to an apricot early tea, or pink hybrid musk might smell similar to an apricot hybrid musk etc. But the pink early tea and pink hybrid musk smell different to each other.

    I never realised that petunias were fragrant until I worked in a large chain garden centre. I spent many hours sniffing the product. To me many of the purple/ blue/ pink/red ones are scented but the yellow ones never were. And as for the cyclamen, it didn’t seem to be related to the colour. We would get large multi-coloured batches where they were all scented, except for the odd one, sometimes purple, pink or red. Other times we would get multi-coloured batches that weren’t scented at all. I could never really make a correlation with the colour.

    1. That’s priceless info, from someone who’s been doing some serious sniffing. Thanks for that.
      How about the polyanthus? Can you confirm that it’s only (or most reliably) the yellow ones that are scented?

  4. I do recall the yellow polyanthus being scented and I don’t remember the other coloured polyanthus being scented, but I can’t confirm it definitively because, compared to many other plants, I spent little time sniffing them. I’ll have to go back to the garden centre to satisfy my curiosity.

  5. Interestingly I have found white cyclamen highly scented but not every day sometimes you get a beautiful amazing scent, other days no scent from the same plant anyone else found this?

    1. Yes, Jillian. I’ve found the same. The perfume is very temperature dependent. I guess that isn’t at all surprising since many of them would be volatiles that are much more active with higher temps, but I haven’t found the perfume on the cyclamen to be predictable on that score

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