Scented petunias

Judith Adam

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Purple Wave petunia. Photo by Brendan Adam-Zwelling
Purple Wave petunia. Photo by Brendan Adam-Zwelling
Purple Wave petunia. Photo by Brendan Adam-Zwelling

Someone has been fooling around with the petunia genes and it could be a good thing. Petunias in my garden last summer were puffing out a heady scent after dusk from their long tube throats, the kind of deep nectar repository hummingbirds look for. I spend quite a bit of time thinking of ways to entice my little hummer to stay longer in the garden, so I’m interested in knowing more about this. Petunias (Petunia x hybrida) are in the Solanaceae family, and related to tobacco and ornamental nicotine (Nicotiana hybrids and species), another flower with a long tube throat and similar scent.

From my completely disorganized survey of petunia scent (which involves sniffing each cultivar as I pass along the nursery aisle), it seems not all petunias are perfumed. This is a highly inaccurate method, because flowers express their perfumes at particular times (often morning or evening) and in certain climate circumstances (high humidity, cool air temperature), and usually smell like nothing at all in mid-day hours at the garden centre. However, it can be said that some petunias are more perfumed than others.

There are many flower sizes, colours, bi-colours and forms of petunias (spreading hedgiflora, grandiflora, multiflora, milliflora, frilled, double). All are bred from two Argentinian species: P. axillaris, with large, highly scented, night-blooming white flowers; and P. integrifolia, with small, almost scentless violet blossoms. These two species have provided ample genetic material for hybridizers to develop a broad colour palette and diverse plant forms. In particular, the breeding work done on spreading petunias (like the Wave, Easy Wave, Tidal Wave, Shock Wave, Avalanche and Ramblin’ Series) allows us to select plants for groundcover in beds, or to cascade down the sides of baskets and containers. And then there are the mounding petunias, in every colour from palest pink to almost true black, with stars, striping, bi-colour veining and multi-colour throats of every kind.

In this plethora of petunias, no catalogue description mentions scent. Most breeding work has focused on colour development and I can say it’s gone way overboard on that, having been startled by some of the garish new cultivars like candy-pink and green ‘Lime Bicolor’. The innovation of self-cleaning plants like Proven Winners’ Supertunia (no more wet tissue paper-type spent blooms) has been useful.

Scent has remained illusive and unpredictable, but there are some worthwhile plants available. The original P. axillaris species can still be grown from seed (anniesannuals.com), and the Tumbelina Mixed Perfume Collection of double flowers has been developed in Britain.

I’ve grown Madness Plum Crazy petunia and it was indeed scented, and perhaps other cultivars with mauve petals bearing purple veining will also have perfume. I know for certain that the yellow and white grandiflora ‘Prism Sunshine’ petunia is deliciously scented at night; and as well, several double petunias (especially mauve-purple cultivars) also are perfumed. Purple Wave also seemed somewhat scented in my garden last summer. Those Argentinian species are floating around in these hybrid plants and the scent genes from P. axillaris seem prominent in white (or white bi-colour), veined mauve single and double purple flowers.

This is not just speculation from a hummer-hopeful gardener. Scientists at the University of Amsterdam have isolated the volatile benzenoid chemicals that synthesize perfume in species petunia petals. It’s known that white P. axillaris emits strong scent after dusk to attract night-flying hawk moths; violet P. integrifolia produces a less intense daytime scent to attract pollinator bees in sunlight. Isolating the scent genes makes it easier to breed new perfumed petunias.

Take no notice if you should see me this spring, sniffing my way down the petunia aisles. I’ll be engaged in serious research!

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9 thoughts on “Scented petunias”

  1. Since I am in the mid-west northern U.S. it is hard to find scented petunias. I’ve found that the solid blue petunia has a pleasant sent. I’ve made it a point this year (2022) to have a pot of them on my deck and a flower tower of the same kind.in front of the house.

    Reply
    • Hi! I did that last year! The scent intoxicating
      The hanging baskets I bought were
      Tritunia Blue Petunias
      Trying to find seeds nearly impossible. Hoping to find hanging baskets this year since we’ve moved .

      Reply
  2. I just walked into the dining room at 7pm (daylight saving) and got hit with a very strong fragrance. Looking around the only thing it could have been was the purple petunia I had in a pot in the window. I didn’t realise petunias had fragrance and was pleasantly surprised. I got this one from Mitre10 garden section (nsw, Australia). I’d been in and out of the room on previous occasions during the day (and other days) but never noticed the fragrance before. Its marvellous!

    Reply
  3. Thank you! I need the more controlled forms of today’s hybrids but petunias loose half their charm without scent. Just ask the bees and hummingbirds! Since I’m buying plants I shall just have to do the nose test down the isles. Wish this was not the case but at least I know the present state of affairs.

    Reply
  4. Thank you for posting this article. I am really interested in growing only the scented types. I have grown the old fashioned heirlooms since one summer, I discoverd this beautiful scent in the evening!
    This year, I am groing Big Daddy Blue and it is more fragrant than the old fashioned petunias heirloom. Keep on sniffing and sharing, I would like to find more since the scent is something I can’t live without in my summer garden now!

    Reply
    • I find that the solid blue petunias have a wonderful scent. I’ve tried growing by seed-the ones called Scentsation, but no success so I’ve settled for getting them at the green house.

      Reply

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