Wednesday Weed – Petunia

Petunias on East Finchley High Street

Dear Readers, petunias are popping up in the hanging baskets and pots of East Finchley. I must confess that I have never been a big fan of the plants, but the great thing about the Wednesday Weed is that it’s made me question everything that I’ve ever known. After all, what is a petunia, and how has it become so popular? What is it related to? Do any insects like it?

Well, petunias come originally from South America – there are about 20 separate species. The plants are members of the Solanaceae or nightshade family, which includes tobacco, tomato and potato, and their name ‘petunia’ comes from the word ‘petun’, meaning ‘tobacco’, in the local Tupi-Guarani language. The Maya and the Inca believe that the plant has the ability to ward off underworld monsters, and there is a belief that petunias bring happiness to a house. They are certainly the most generous of plants, pouring forth their blooms for months at a time. No wonder they are many people’s first choice for a hanging basket.

Photo One by By ElenaSchifirnet - Own work, CC BY-SA 3.0,

Floral Arrangement in Columbus, Ohio (Photo One)

The ‘domesticated’ petunia is a hybrid between two species, Petunia axillaris (the white moon petunia) and Petunia integerifolia (violet petunia). The white moon petunia has a sweet smell which has been inherited by some forms of the cultivated petunia, while the violet petunia is said to be used as a hallucinogen in Ecuador, giving a sensation of flying.

Photo Two by By Magnus Manske - Own work, CC BY-SA 3.0,

White moon petunia (Petunia axillaris) (Photo Two)

Petunia integorifolia from Edward’s Botanical Register 1833 (Public Domain)

The cultivated petunia is known as Petunia x atkinsonii. Incidentally, this is an example of a nothospecies – a new word to me, so I had to investigate. A nothospecies is a hybrid between two plants in the same genus, as here. If a plant is a hybrid between two plants of different genuses, it’s known as a nothogenus. Who knew? Certainly not me, who has enough trouble finding two matching socks at the moment.

Anyhoo, back to the petunia. It seems to tolerate drying out better than some other plants, which makes it ideal for the exposed environment of a hanging basket. It isn’t overfond of conditions that are too damp or shady – it is said to need at least five hours of full sunshine every day. It pairs beautifully with pelargoniums (which need similar conditions) and there is definitely a petunia for every colour scheme. There are the ones which are divided into segments:

..the ones where the edge of the petal is a different colour from the middle…

the ones with defined veins in the petals…

Grandiflora petunia ‘Blue Daddy’ (Public Domain)

and my favourite, the ones that look like starry skies….

Photo Three by By EliasTheHorse - I took it on a flower's shop., CC BY-SA 4.0,

‘Starry Night’ petunia (Photo Three)

One definite disadvantage of the petunia from my point of view is that, pretty as it is, it doesn’t seem to attract many insects. All the species bar one are pollinated by insects, and rumour has it that petunias are sometimes visited by hummingbird hawk moths, as evidenced by several photos.

Photo Four by David Short from Windsor, UK [CC BY 2.0 (]

Hummingbird hawkmoth popping in for some petunia nectar (Photo Four)

Being a plant of hanging baskets, the seeds of petunia are often scattered far and wide, and the seedlings can sometimes be seen popping up in the cracks in the pavement during the following spring. The paving stones by the side of pubs are a particularly good spot – some pubs pride themselves on their floral displays, and there are several in London that really exceed expectations. Perhaps the finest is the Churchill Arms in Kensington, which spends £25,000 a year on its floral display, and very fine it is too.

Photo Five from

The Churchill Arms in Kensington (Photo Five)

Allegedly, petunia flowers are edible, though no one seems to get very excited about them. I was a little disappointed to see that the ‘Petunia Bowl’ salad that I found online was an homage to The Hitchhiker’s Guide to the Galaxy (in which two thermonuclear missiles turn into a whale and a bowl of petunias) and actually contains no petunias, though as there is some thought that the petals might be poisonous it’s probably just as well.

Now, here’s a fascinating thing. A couple of caterpillar larvae do eat the flowers of petunias, and both are serious pests of agricultural crops. One, the corn earworm (Helicoverpa zea) is the second most serious insect pest in the USA, munching its way through corn, tomatoes, cotton and a dozen other plants. Not only does it decimate plants but, most unusually for a moth, the caterpillar will also eat other insects.

Photo Six by By cyanocorax -, CC BY-SA 2.0,

Corn Earworm (Helicoverpa zea) larva (Photo Six)

The  other species that feeds on petunia is the cabbage looper caterpillar (Trichoplusia ni) which, as its name suggests, normally prefers brassicas, red cabbage in particular. As this is a vegetable that I find it hard to get excited about, I am prepared to give this little chap rather more garden-room. Plus, it does that ‘inch worm’ walk that I found so appealing when I was a child.

Photo Seven by By Alton N. Sparks, Jr., University of Georgia, United States - This image is Image Number 1327034 at Forestry Images, a source for forest health, natural resources and silviculture images operated by The Bugwood Network at the University of Georgia and the USDA Forest Service., CC BY 3.0,

Cabbage looper ‘looping’ (Trichoplusia ni) (Photo Seven

Now, in a study by the scientists at United States Department of Agriculture in Peoria, Illinois, it has been found  that when the caterpillars of both species were fed on bi-coloured petunias like the one below, they much preferred the white sections to the coloured ones. When given no choice but to eat the blue bits, they put on much less weight, and a much higher proportion of the larvae died. The hypothesis is that this is due to the natural anthocyanins in the blue petals, which act as a natural insecticide. Such pigments are energetically expensive for a plant to produce, but of course these plants have been bred rather than emerged through natural selection. The question is whether these pigments could have a wider application, and how much effect they would have if they could be bred into food crops. Fascinatiing stuff.

Bicoloured petunias, similar to the ones fed to the caterpillars.

And here’s a poem. I’ve had to read it once or twice to get under its skin, but it’s worth it. I regret that I hadn’t come across Bob Hicok before – he was born in 1960 in Michigan, and had worked for years in the automotive industry before he discovered his gift for poetry. He is most famous in the US for his poem series about the shootings at Virginia Tech. Someone commented that “Hicok’s meditations… do not allow us to turn away from the act of violence, neither from the person who committed the act, nor from the ironies of survival.” See what you think.

The semantics of flowers on Memorial Day

Historians will tell you my uncle
wouldn’t have called it World War II
or the Great War plus One or Tombstone
over My Head. All of this language
came later. He and his buddies
knew it as get my ass outta here
or fucking trench foot and of course
sex please now. Petunias are an apology
for ignorance, my confidence
that saying high-density bombing
or chunks of brain in cold coffee
even suggests the athleticism
of his flinch or how casually
he picked the pieces out.
Geraniums symbolize the secrets
life kept from him, the wonder
of variable-speed drill and how
the sky would have changed had he lived
to shout it’s a girl. My hands
enter dirt easily, a premonition.
I sit back on my uncle’s stomach
exactly like I never did, he was
a picture to me, was my father
looking across a field at wheat
laying down to wind. For a while,
Tyrants’ War and War of World Freedom
and Anti-Nazi War skirmished
for linguistic domination. If
my uncle called it anything
but too many holes in too many bodies
no flower can say. I plant marigolds
because they came cheap and who knows
what the earth’s in the mood to eat.

Photo Credits

Photo One by By ElenaSchifirnet – Own work, CC BY-SA 3.0,

Photo Two by By Magnus Manske – Own work, CC BY-SA 3.0,

Photo Three by By EliasTheHorse – I took it on a flower’s shop., CC BY-SA 4.0,

Photo Four by David Short from Windsor, UK [CC BY 2.0 (]

Photo Five from

Photo Six by By cyanocorax –, CC BY-SA 2.0,

Photo Seven by By Alton N. Sparks, Jr., University of Georgia, United States – This image is Image Number 1327034 at Forestry Images, a source for forest health, natural resources and silviculture images operated by The Bugwood Network at the University of Georgia and the USDA Forest Service., CC BY 3.0,

13 thoughts on “Wednesday Weed – Petunia

  1. Alyson

    I rarely plant petunias nowadays as if there is a wet summer they seem to dissolve in the rain. Not so fond of the stripy hybrids but love many of the ones you have shared with us here.

    1. Bug Woman

      In my experience, they either dry up or melt, but the pubs seem to have it about right! My dad really loved the ‘starry night’ ones.

  2. Toffeeapple

    I have not had them for many years but when I see them I always have to breathe in the scent from the deep blue ones. Are those the only ones with perfume?

  3. Sarah Ann Bronkhorst

    Thank you for yet another clever, wry poem from a poet new to me, too. Fits well with ‘Catch 22’ on TV.

  4. Alittlebitoutoffocus

    You’re obviously talking my language here – on two fronts, the petunias and pubs in Kensington… Every year since we’ve had the chalet we’ve bought petunias, though they do need a lot of maintenance, dead-heading them. So latterly, our hanging baskets and balcony boxes have had a mix of plants. And, yes, we often see the Humming-bird Hawkmoths flitting about. They are amazing to watch. (I’m sure I’ve posted some pics in the past, but couldn’t tell you when). As for the pubs, I used to frequent the Windsor Castle and Elephant and Castle, while at Uni. Though I dare say I did pop in to the Churchill sometime. Happy days, though I had no interest in flowers (or butterflies for that matter) back then! I hope your ankle is better and you enjoyed Austria.

    1. Bug Woman

      Thanks, Mike! Yes, finding out about the hawkmoths has raised the humble petunia in my estimation – I used to think that they were completely useless for pollinators, so I’m glad that I was wrong. And I do love me a good pub hanging basket….

  5. tonytomeo

    I would guess that, like nasturtium, trailing rosemary and ivy geranium, the common petunia became popular in window boxes because the aromatic foliage was though to repel mosquitoes.
    I remember that red, white and blue petunias were very popular in the summer of 1976, and that the big palms on Bedford Drive in Beverly Hills (in the Los Angeles region) had big circular beds of uniform colors around them. Each big bed was one of the three colors, alternating red – white – blue. It was rad.

    1. Bug Woman

      Hah! We used to have beds with white alyssum, blue lobelia and red bedding salvia in the shape of the Union Jack. I suspect that outside the cities that’s still the desired format, though some councils are getting with the ‘planting for pollinators’ stuff, and plant bedding that at least has some value to wildlife.

      1. tonytomeo

        Yup, we used that same combination for ‘color bowls’ around the Fourth of July back in the 1990s, although not for big beds. It was rad!

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