Big mystery. Their height and flower size would seem to rule out them being Profusions or Zaharas. However, them not having mildew doesn't necessarily mean they are mildew resistant. It could be that the plot tender gave them a big dose of systemic fungicide, which would make them mildew proof for awhile, until it "wore off" or the tender gave them another dose. Best thing to do would be talk to the plot tender and find out what his secret is.

I do use a systemic fungicide to extend the life of a few of my "breeder quality" zinnias. The stuff is fairly expensive, so it would be impractical to use it on a large scale.

ZM

For some reason, Magellan zinnias comes to mind. Not that I have grown them; have just been studying catalogs lately.

Hi Alex,

Magellan zinnias are a dwarf variety, only 12 to 14 inches high. These "mystery zinnias" are 2 to 3 feet tall. So they are not Magellans. OK, eating crow. See the messages below. Grin. I am going to learn to pay more attention to you.

The Powdery Mildew that infects zinnias is caused by a fungus that is specific to zinnias of the species Z. violacea (elegans). So, it is highly unlikely (read impossible) that any zinnia of that species can be genetically immune to Zinnia Powdery Mildew. But "unlikely" doesn't rule out the possibility altogether.

I wondered if tetraploid zinnias might be immune, due to their doubled chromosome number, so I grew some Burpee tetraploid zinnias and the heirloom tetraploid, State Fair. Both of those tetraploid strains exhibited vulnerability to Zinnia Powdery Mildew equal to the diploid zinnias I was growing beside them.

The zinnias in the pictures look just like Z. elegans (violacea), so I think it highly unlikely that they have a genetic immunity to Zinnia Powdery Mildew.

Mantis_oh mentioned that the PM-free zinnias were growing in a community garden. It is possible that the previous user or the present user of that plot deliberately or accidentally put something in the soil that those zinnias have absorbed that conferred their apparent PM immunity.

Or, it simply may be that there are no zinnias growing in the immediate neighborhood of that community garden, so that those zinnias simply haven't been contacted by a spore or spores from the Zinnia Powdery Mildew fungus. I believe that fungus can only grow on zinnias, so zinnias can "catch" the disease only from spores from other zinnias. The spores can be airborne.

I have wondered from time to time if zinnias could take up Selenium from soils that contain Selenium, and if they did, whether that Selenium would confer immunity to diseases. I am not about to add Selenium to any soil, because once you do, you simply can't get it out. And you would run the risk that anything grown on that soil would be poisonous. However, people have been known to treat the potting soil that African Violets are growing in with a Selenium-containing agent to combat some African Violet problem. People don't eat African Violets, so making their plants toxic is allowable. A trace amount of Selenium is actually good for you, and I have seen Selenium pills for sale in a health food store. But Selenium can be toxic to humans and to animals. The so-called "Loco Weed" in Texas accumulates Selenium from the soil and cows that eat the weed "go loco".

But we still don't know why those zinnias don't have PM. I just highly doubt that it is their genetics.

ZM
(not associated with any product or vendor mentioned or linked)

This post was edited by zenman on Thu, Oct 16, 14 at 15:21

I wonder if these are the Sun hybrids. Some of the flowers are quite large--more like 4 inches and up. You are right Zenman that there are not other zinnias around; it is basically a vegetable garden. Also there is a lot of space between plants. Still, it is amazing how floriferous and disease-free these plants are. Stokes, by the way, calls Red Sun a mildew-resistant cultivar. I have never grown the Sun series, so I am not familiar with it.

Another possibility is that they are Zahara zinnias that have grown especially large. Some plants are almost 3 feet tall, whereas others are about 18 inches.

Another po

This post was edited by mantis__oh on Wed, Oct 15, 14 at 17:14

The Zaharas are a little higher then Profusions, and they have slightly larger flowers as well. The Zahara height is listed as 12 to 18 inches. There is a so-called "knee high" variety of Profusion that is a couple of inches taller than the standard Profusions. But neither Profusion nor Zahara approach the height and flower size of your pictured zinnias.

They could be Sun hybrids. From time to time various zinnia strains are listed as "disease resistant" without really defining the term. I don't know of any Zinnia violacea (elegans) strains that don't get various zinnia diseases, including powdery mildew.

ZM

I ordered and started only Magellan's this year because they were advertised to only reach 14 inches. What I ended up with is beautiful plants 3 feet tall and look very similar, if not identical to, those pictured above.

Hi geosankie ,

Very interesting. Did yours seem to be mildew resistant as well?

Oh, and also. Just out of curiosity, if you don't mind saying, who did you order your Magellans from?

ZM

This post was edited by zenman on Thu, Oct 16, 14 at 13:01

Got the seeds from Swallowtail and never had any fungus problems right up until 2 days ago when the frost finally got them.. happy with the plants but was hoping they were a little shorter. I didn't measure them but they are at least 30".
Bed is 18 feet long by 4 feet wide and became solid Magellan's.(supposedly)..no disease whatsoever.

Hi geosankie ,

Thanks for the info. I will be ordering some zinnia seeds from Swallowtail. Actually, I was going to order some different zinnia seeds from them anyway, but now I will be adding some Magellans to the order.

ZM

I think they might be Zaharas, possibly Double Cherry. The blossoms are between 2 and 3 inches across and they are bred to be resistant to many diseases. I grow them and I don't use any kind of systemic fungicide and have not had problems at all. Your photos also look amazingly like mine and I went back to find out where I purchased mine from. Hope this helps

Here is a link that might be useful: Zahara Double Cherry

Hi grandmamaloy,

The Double Cherry Zaharas are described as having blooms 2.5 inches in diameter and plants 12 to 18 inches high.

The Original Poster (mantis__oh) described the pictured zinnias as around 3-inches in diameter (a possible description for Zahara blooms) but 2 to 3 feet tall -- twice the height of the Zaharas. Of course, their height also doesn't match the Magellans, which geosankie reported as reaching 3 feet tall.

But you are right that Zaharas have better disease resistance than Magellans, so that would tend to favor your suggestion. However, I personally don't know of any 3-foot disease resistant zinnias.

ZM
(not associated with any product or vendor mentioned or linked)

This post was edited by zenman on Fri, Nov 14, 14 at 17:35

Note that the plants varied a lot in height. A few were near three feet, but some were only about 20 inches. The soil was probably especially rich. Note too that there was a wide range of colors, though some colors, particularly yellow, were shorter than others. All were at least semi-double; some more double than others.

This post was edited by mantis__oh on Wed, Nov 19, 14 at 21:02

Hello , does anyone have any idea which of swallowtail gardens seeds are diploids/tetraploids ? I asked them and they said they think that the Sungod cactus zinnias and super cactus lilac emperor zinnias are tetraploids, and they don’t know about any of the other zinnia seeds . I really want to breed zinnias at home , but I want to avoid unintentional Tripolid crosses . i Would greatly appreciate if anyone can give me an idea of which seeds are diploids and which are tetraploids. Thanks

Hello HU,

" ...does anyone have any idea which of swallowtail gardens seeds are diploids/tetraploids ? I asked them and they said they think that the Sungod cactus zinnias and super cactus lilac emperor zinnias are tetraploids, and they don’t know about any of the other zinnia seeds. "

Excellent question. Zinnia seed retailers don't say which varieties are tetraploid, for one reason or another. They seem to think that gardeners either don't care, or if they said, it might even cost them sales of some tetraploid zinnia seeds. The only seed company that I know of that tells you which zinnias are tetraploid is GeoSeed, and they are one of my "go to" companies for zinnia seed (they also carry zinnia species, including Zinnia peruviana and Zinnia tenuifolia.)

So, at least a partial answer to your question is that, according to GeoSeed, the Super Cactus Giant Mix are seven bright colors of tetraploid zinnias. Apparently "super" is a code-word for tetraploid. From that I infer or deduce that Swallowtail's new for 2020 Super Cactus Sungod yellow zinnia is tetraploid, as they told you. Although the word "super" is not always applicable, I also suspect that Senora, Giant Cactus Pinca Mix, Pinca, Inca, and Super Cactus Lilac Emperor are all tetraploid.

" I really want to breed zinnias at home , but I want to avoid unintentional Tripolid crosses . i Would greatly appreciate if anyone can give me an idea of which seeds are diploids and which are tetraploids. "

You would be most welcome over at the "It can be fun to breed your own zinnias" message strings.

ZM

This is Hu- Thanks Zen man 🙏. It was very helpful information. I’ve decided that making triploids on purpose might be fun , and am going to try testing any uncertain varieties. I will be testing ”unknown “ varieties by crossing them with a known diploid or tetraploids and seeing which plants are infertile 😊!

Hello Sarah (aka HU),

Making triploid zinnias on purpose can produce some amazing results. Triploid zinnia plants can grow to amazing plant sizes. This triploid was an "accident" of mine, that occurred when I was experimenting with tetraploid zinnias to see if they were resistant to Powdery Mildew. (They were not any more resistant than normal diploid zinnias--the tetraploids also got PM.) I guess a bee did the cross-pollination that produced the triploid seed. (You can click on the photo for a bigger view.)

That is a single zinnia plant and it eventually grew to more than twice that size (with about a hundred blooms open) when a killing freeze got it. You can see a "caged" normal diploid plant in the upper right-hand corner of that photo. That triploid plant did not get Powdery Mildew, although it may not have been exposed to PM. So I guess the Jury is still out on Triploid Zinnias and Powdery Mildew. But triploid zinnias can develop amazing plants.

It may not be necessary to do your testing of ”unknown “ zinnia varieties by crossing them with a known diploid or tetraploids and seeing which plants are infertile. I read somewhere that you can tell by examining parts of the zinnia plants under a microscope. The leaf hairs of tetraploid zinnias are noticeably "fatter" than the leaf hairs of diploids. (I don't know if you can distinguish triploids from their leaf hairs--maybe). Also, the stomata of the leaves (the little breathing holes--I guess you could say "nostrils" of the leaves) are noticeably different between tetras and diploids. (I plan to purchase a microscope that I can take with me into the garden.)

I wouldn't be surprised if you could sell your triploid zinnia plants at a local garden center. You might also experiment with propagating cuttings of your triploid zinnias. Triploid zinnias have a lot of possibilities.

ZM

Hey ZM,big fan of your zinnias.Im totally taken by Burpees Forecasr zinnia and wanted to know will they breed with other zinnia varieties like State fair and California giants.I like the LARGE growing zinnias with daisy like flowers for my butterflies and pollinators

California giants and Scarlet

Hello Christopher,

" I'm totally taken by Burpees Forecast zinnia and wanted to know will they breed with other zinnia varieties like State Fair and California Giants. "

I have never grown Forecast because I am not a fan of single zinnias. So my answer here is somewhat guesswork. Forecast will probably breed with other zinnia varieties. My guess is that Forecast is diploid, so crossing it with State Fair, which is tetraploid, would produce an interesting triploid zinnia which, like all triploids, would be sterile (incapable of setting viable seeds.) Once again, assuming Forecast is diploid, crossing it with California Giants (also diploid) would create some interesting large zinnias. Incidentally, Forecast was on the cover of the Burpee seed catalog a few years ago. I think Forecast may be a Burpee exclusive.

It sounds like you would like to breed larger single zinnias for butterflies, and you are "on the right track" to include Forecast in your breeding. Another zinnia that produces a lot of pollen (which contains the nectar for butterflies) is the award-winning Zinnia Zowie Yellow Flame (that is a clickable link) Zowie's tall central cone produces a lot of nectar for the butterflies. I recommend you include Zowie in your breeding program.

ZM (not associated with any product or vendor mentioned or linked)

Hello again, anyone who is still around.

I am totally annoyed and disappointed that Houzz has replaced the photos in the leading message of this message string with totally unhelpful "codes" as follows:

{{gwi:25696}}

{{gwi:25697}}

{{gwi:25698}}

Really, Houzz?? Is this the best you can do? You have similarly gutted all of my old It Can Be Fun to Breed Your Own Zinnias message strings. Apparently, the worst thing that could happen to us was for Houzz to take over the Garden Web. Maybe "worst" is overstating it, but it was a bad thing to lose all those photos.

I have decided to experiment with triploid zinnias, so I will be giving myself a "late" Christmas present of a microscope early next year. I want to be able to tell which zinnias are tetraploids by examining them microscopically. These were a few of my recent "breeder" zinnias. (All diploids) You can see larger versions of the photos by clicking on them, and you can dismiss the larger version by clicking on the X in their top-right corner.

I will be keeping those photos safe on an external drive.

ZM

^^ I really like that last one, reminds me of a candy cane.

Hi mxk3,

The Whirligig strain of zinnias was produced by hybridizing two different species, so their progeny can be referred to as Zinnia hybrida, and multi-colored blooms are fairly common in that genetic mix, which is most of my "home hybrids".

Crossing mult-colored zinnias is kind of fun.

ZM

Hi guys,

Have you ever noticed how much white space winds up between the photos here? You can see a good example of that in the last message, the one just before this one. I kinda would like to figure out how to make the photos closer together. Maybe I will do some experiments, and maybe I will ask Houzz about that. Apparently Houzz inserts a blank line after each Carriage Return and that is OK for text but not for photo thumbnails.

ZM

Hi guys,

Experimenting with photo location again.

That was a Houzz photo I uploaded. So, the Houzz photos I upload apparently behave the same as my photos inserted using Houzz's Photo icon. I couldn't "trick" this Houzz software to do the "correct" thing.

ZM

Glad to see your still into growing zinnias,Your "it can be fun to grow zinnias"series is AMAZING . Hopefully you have been able to capitalize off of it like posting it on Tik Tok,IG etc.I'm getting back to growing my zinnias this spring to attract the butterflies and hummingbirds.I'm sticking to Forcast,State fair, California Giants and all the large single pedal varieties.

Wow,That plant looks very vigorous and healthy,that's how mine looked,no powdery mildew,no diseases.I have a gazillion seeds saved from 2021 and 2022They are very HYBRIDIZED with State fair, California Giants,Scarlet Flame, Purple Prince,Orange King,Forecast,Canary Yellow and Cherry Queen being there lineages.All the hummingbirds,bees and butterflies did a GREAT job of cross pollinating.This year I'm adding a dwarf variety of Mexican sunflower and American basket flower.