Hi SCG, The Whirligig strain from Park Seed has a high percentage of singles. Those zinnias come in an amazing array of two-color and three-color blooms, and the single flower form shows off those individual color schemes to a good advantage. I prefer double zinnias myself, so I get my Whirligigs from Stokes Seeds, whose grower maintains a Whirligig strain with a high percentage of doubles. But double Whirligigs do lay petal-over-petal, which tends to conceal the remarkable petal colorations that the singles display so well. The single Whirligigs can have some spectacular blooms in an almost endless variety of color combinations. ZM (not associated with any product or vendor mentioned or linked)

Shelley, I have been giving your question some thought and poked around the web a bit but I have come up blank. The only far stretch thought I have is perhaps the lack of color on one plant is due to root disturbance from voles? Or maybe as this perennial is getting somewhat older this is just one of those first signs of old age, sort of like all of the wrinkles that have been showing up on my face. I am curious what others might think. kt

Hi Highlander, " Supposedly it's fairly difficult to get a good looking new dahlia breed from seed. " Yes, dahlia breeding, like rose breeding, and most breeding of asexually propagated ornamentals, proceeds by making crosses between hybrids of hybrids of hybrids, ad nauseum. So the existing specimens that you grow and cross-pollinate are themselves highly heterogeneous. So your dahlia crosses will product highly recombined progeny, and they will be full of surprises, most of them rather disappointing, depending on your standards and goals. " If I were to catch a new freshly opened flower bud from the thread related zinnia, and I were to carefully pollinate it manually using pollen from another flower from the same plant, and then isolate it from further pollination by bees carrying pollen from other plants, will it produce flowers with seeds that produce plants with flowers that look the same as these? " Many will be similar, a few will be noticeably different, and a few will be approximately the same. Zinnia populations (like many things) are a Bell Curve kind of thing, with average quality specimens in the head of the bell and a few really good (desirable) and a few really bad (undesirable) specimens in the tails of the bell. Depending on your standards, it takes 5 to 7 generations of careful selection to produce a reasonably pure strain of a zinnia. You aren't going to "get there" in a single generation. I have found a serendipitous thing about trying to stabilize a target strain of zinnias. The random recombinations of genes that appear in your specimens will produce a few specimens that are reasonably similar to your "target" for the strain, but you can get a few recombinants that are actually improvements to your target, and those will usually cause you to redefine your target and self them. Sometimes you will get more than one new target in that process. That is why I frequently say that zinnias are full of surprises. As an example, in my zinnia breeding a few years ago I set out to develop a stable strain of a tubular petaled mutant. The starting point had a red color: and I wanted the strain to have all zinnia colors and larger blooms, so I crossed the red tubular with many different colors of larger zinnias to produce a generation of F1 hybrids. Alarmingly, those produced a variety of different colors and sizes in the F1 generation, but the tubular petal form was gone. I hoped that the tubular trait was just recessive, so I selfed and re-crossed the F1's to produce my F2's and, sure enough, the tubular trait reappeared in a variety of colors and sizes. But I also got recombinant tubulars with much slimmer tubes, and these suggested a second "target" for my tubular project. Zinnias can be full of surprises. " Are zinnias pollinated by wind or by incidental contact with each other or only by insect or bird pollination? " Zinnia pollen grains are too big and heavy to be considered wind pollinated, but air currents within a zinnia bloom can move pollen grains within a bloom. It is unlikely that wind will do any significant amount of pollination between different blooms. Gravity can also carry loose zinnia pollen down from a pollen floret to stigmas below it. Hummingbirds, butterflies, skippers, and day-flying moths seem to get the zinnia nectar from the florets with minimal disturbance, so they are a minor contributor to pollination. Incidental contact could contribute a minor amount of gravity or micro wind current pollination. Bee disturbance, combined with gravity or micro wind currents are probably the main pollination mechanisms. And, of course, the pollen florets are internally pollinated to produce the selfed floret seeds. A pollen floret contains an internal anther bundle and a stigma that pushes up through it to push the pollen out and that stigma usually gets self-pollinated in the process. " The crazy thing is that I had no yellow flowers at all last year, but I ended up with a lemon yellow single this year, which came from a thick double flower that was velvety red! " Yes, the genetic process of recombination can reveal previously hidden traits. Zinnias are full of surprises. ZM

Since you mention its on a branch.. if its the longest or largest laden with buds of the plant.., it could be all nutrients donot reach it... you may wanna try spray fertilize when not in bloom ? I have had such issues, i snip that branch. some cases the issue is sorted if its localized... buti have also had plants where it happens each year after moving to a larger pot with rich soil aswell... but i try and play around with them rather than throw away:)