Wednesday, September 5, 2018

Wednesday Vignette: What's going on here?

I recently noticed some odd flowers on the Pelargonium peltatum (ivy geranium) that's growing up the arbor above the gate that leads from my cutting garden to my dry garden.  A handful of flowers were smaller and lighter in color than the rest.  My first thought was that maybe the flower buds had been scorched by the intense sun that accompanied the extreme heatwave in July.  I deadhead the shrub regularly so the unusual flowers were soon gone and I didn't think about them again until I noticed yesterday that they'd reappeared.

The photo on the left shows the flower's usual appearance and the one on the right shows the anomalous blooms

This is a fuller view of the plant, which I brought with me in a pot when we moved here 7+ years ago.  Only a few of the smaller, lighter blooms are showing at present.

I know that plant viruses are responsible for much of the variegation we see in foliage and I remembered that a virus was responsible for color breaks in tulips.  I conducted a cursory search and discovered that such breaks have also been observed in Pelargoniums.  This is what a 1989 study by The University of Illinois Extension said:

This rare disease is caused by the Pelargonium flower break virus (PFBV). Although serologically distinct from other viruses that infect geranium, PFBV is difficult to detect because it occurs in low concentrations in the plant and is symptomless in most cultivars. Susceptible geranium cultivars show a breaking of flower color which appears as light colored streaks in the petals. Plant growth is retarded and flowers are smaller with rugosed petals. The virus has only been isolated from P. zonale and attempts to infect P. peltatum have failed. The virus is transmitted by infected cuttings, grafting, and sap.


While the 1989 study cited no evidence of PFBV in ivy geraniums, a 2012 article in a scientific journal listed Pelargonium peltatum as another host for the virus.  How my plant was infected isn't clear to me.  I'm going to cut back the plant as usual this fall and wait to see what happens.  The references I scanned indicate there's no known treatment for this virus.

Coincidentally, I noticed that one of the dahlias in my cutting garden, 'Punkin Spice', also produced flowers in two distinctively different colors on the same plant this week.  The colors of dahlia blooms can change dramatically as they mature but these two blooms opened at almost exactly the same time.

The maturity of the bloom isn't a factor in the color differences shown here

This photo shows the 2 flowers on the same plant, although growing on different stems


Looking into this anomaly yielded the conclusion that variations among dahlia buds on the same plant are quite common and in fact have been exploited in developing new varieties.  I've no intention to get into breeding dahlias at this point, however.

This overview of floral anomalies is my Wednesday Vignette.  Visit Anna at Flutter & Hum to see what images she and other contributors have found of interest to share this week.


All material © 2012-2018 by Kris Peterson for Late to the Garden Party

24 comments:

  1. The flower weirdness in your Pelargonium is interesting, but I'm also still trying to get my head around the fact that it grows in the ground there, like a shrub.

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    1. Pelargonium peltatum in particular does very well here, although that particular plant surprised me when it elected to climb up the arbor and mingle with the Pandorea jasminoides.

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  2. I'm impressed that you did so much research. And I am awed at the size of that Geranium and that you've had it so long (and moved it as well).

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    1. I guess spending so much of my life living with a scientist has rubbed off on me, Linda. If you don't know the reason for something, conduct research. If you don't have data to draw a conclusion, gather it. If you need to make a point, put together a graph. I've been on the receiving end of a LOT of graphs...

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  3. Which of the Dahlia blooms is as advertised and which is the sport? They're both attractive.

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    1. That's a good question, Nell. Actually, neither of those 2 flowers represents what I'd heretofore considered the norm for this particular dahlia. Most have opened as a warm true pumpkin color with the yellow and red tones emerging more clearly as the flowers mature. I don't remember anything like this degree of variability in the bloom colors occurring last year.

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  4. You learn something new every day, don't you??? I shall file this away for future reference! Gorgeous dahlias, in both cases!

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  5. It is always interesting to get differences on the same plant. I hope your ivy geranium isn't doomed!
    I collect a handful of scarlet runner beans every fall to plant again in spring. This year one plant has bloomed with a white lower lobe instead of the all orange. As you said, I guess this is how new varieties come into being. I'm going to set aside a few of these seeds to see if they come true again next year.

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    1. Genetic variations seem to account for the differences in dahlia colors and, as best as I can tell, they're not generally harmful to the health of the plant but it sure sounds as though the Pelargonium virus is a different matter. While I'd hate to lose that Pelargonium after its ambitious effort to climb the arbor, at least it's easily replaced if need be.

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  6. Fascinating stuff. Thanks for sharing the info with us. The variations in color are pleasant, but I hope your plants will be OK.

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    1. I'm sure the dahlias will be fine, Beth. The jury's still out on the impact of PFBV on the Pelargonium. I've got 3 Pelargoniums planted along that fence, all with flowers in the same color, and I've seen the first signs that the virus may have spread to the next plant in the line-up.

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  7. The word virus is concerning, but is it actually harmful? Do you dislike the “new” flowers?

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    1. I don't dislike the new flowers but I don't especially care for the mix of the 2 colors. The 1989 study suggests that the virus can retard plant growth as well as causing the production of smaller and differently colored flowers, which is of some concern. Neither is a major issue at the moment, though.

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  8. My goodness. I have never seen an Ivy Geranium this large. It is so pretty. The virus part is a lovely color. Interesting how this happens, in other plants too.

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    1. I'm wondering if I inadvertently caused the "infection" (e.g. by using tainted pruners, which I'm lazy about cleaning).

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  9. If the virus isn't harmful to the health of the plant, I'd enjoy the color variations. Such a big pelargonium!

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    1. That Pelargonium surprised me when it climbed like that, Peter. It didn't happen until it'd been in the ground a few years and then it shot up when I wasn't looking.

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  10. Pretty! Hopefully the virus isn't harmfull... And I had to laugh about your comment about being on the receiving end of a lot of graphs - do you mean that's not normal? :)

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    1. I'm sure you'd be VERY comfortable in our household, Renee! I used to get pie charts showing my expenses by category - thankfully, that's stopped.

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  11. I tried getting a Pelargonium to grow up one of my arches. Fail! Yours doing that is so cool.

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    1. I can't say I coerced it, HB. It did it on its own when I wasn't looking. However, that happened a good many years after I plopped it into the ground so maybe it just takes time - and something handy to climb on. This one wove itself into a previously established vine.

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  12. I love what the virus has done to your flowers. The pelargonium is a gorgeous color. It will be interesting to see if this anomaly remains, assuming that both your pelargonium and your dahlia flower again next year.

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    1. I wouldn't mind it if all the flowers took on the colors prompted by the virus, Jenny, but thus far it's just a few here and there. I'm loving the variations in the dahlia colors.

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