Many long years ago I used to hybridize zinnias as a hobby, starting as a kid on our home farm. Then for many years I either didn't have enough gardening space or free time away from my job to indulge the hobby. I am now retired and for the first time in a long time I have some gardening space and free time, so I think I will at least dabble in amateur plant breeding again.
However I tend to make crosses between crosses with the result that when something really nice does appear that the saved zinnia seeds are highly variable because of complex hybrid lineage. It would be a big help if I could take a number of cuttings from such a good zinnia specimen and cuttings from those cuttings, to greatly increase the number of seeds that I could save from such a lucky find.
I have had some limited success with zinnia cuttings so that I know it can be done, but I need to improve the technique in order to make it practical for me. In particular, I need to find a way to speed up the process by starting with much smaller pieces of the plant and I think I need a better root stimulating compound than RootoneŽ.
I also tried some grafting experiments with much less success. Some gave some indication of "taking", but eventually withered and died.
I guess propogating zinnias from small cuttings would come under the category of soft tissue cuttings. I'm not quite ready to try tissue culture yet, although that idea is in the back of my head.
There was a widely posted Chinese micro cutting method based on proprietary root stimulating compounds. However, acquiring that method required entering into a contract with the Chinese company and putting up a considerable amount of cash, so that approach is out for me. You may have seen it posted somewhere. Many forums removed the post as blatant advertising and took it down. It was not well translated and rambled on and on, so it was rather difficult to follow. The intended market was for rather large plant propogating companies. But an affordable version of such a micro-cutting method for the home gardener would be very attractive to me.
Anybody have any relevant information for small-cutting propogation of zinnias? Or a technique for small soft-tissue grafts?
For maximum number of zinnia cuttings, I recommend that you do not pinch your plants. Give plenty of nitrogen to produce long, lanky plants. Bright light is still recommended to avoid excessive intermodal length. Cut a stem of zinnas of leaving only a few leaves on the plant. Cut the stem into sections with minimum 2-3 buds. Strip leaves from bottom buds and leave some leaves on the cutting. Root in well draining soil. A tall zinnia plant can produce 6-8 cuttings. Each will be able to produce another 1-2 stems of cuttings in a season.
I would not think grafing works because of the highly freshy nature of a zinnia.
Thanks, Ken, for your response. The thing about not pinching kind of surprised me, but getting lanky plants with tall stems and more cutting material makes sense.
One of my problems is that many of my zinnias are selected for compact bushy plants, very different from the Benary's Giant series. The tall Benary's Giants would lend themselves to producing long, lanky stems. For zinnias in the Magellan, Peter Pan, Dasher, and Parasol series, the stems are naturally shorter and the plants take a lower more branched form. I'll experiment with them to find what works best because I probably can't get a long cutting material section from them.
Its been my experience with cuttings, that the ones that root the best and fastest with soft tissue cuttings are the tips. In which case you would want to pinch back. I would try both ways. Zinnias are so easy to germinate (cover with black plastic while germinating) I just did some and they popped in 2 days, so pot a bunch up and start to experiment. I have never done cuttings with zinnias myself. I have also done experiments with using rooting hormones and not using them in same liner and found there was no difference in time rooted or amt of roots produced-but these were soft cuttings. Let us know what works.
Thanks for sharing your experience with cuttings. I will take your advice to experiment with the tips as well as with sections of stems. I am a big believer in experiments. I have had some limited success in the past with both RootoneŽ and TransplantoneŽ, but so far I haven't really developed a dependable asexual reproduction scheme for zinnias.
I have heard that "willow water" is also capable of stimulating root growth on some cuttings. We don't have any willows on this property, but I may try experimenting with the chemical active ingredient of willow water. However, there is some question as to what the active ingredient in willow water actually is. Some have given it the name rhizocaline, http://www.ars.org/About_Roses/propagating-cuttings.htm which has never been isolated or identified (that makes it seem marginally mythical). However, based on that article, I may try to obtain some commercial Hormodin II.
I was just reading about rooting hormones-liquid ones that you would water into a plant that was already growing, and I came across an experiment done with various rooting hormones -both powder and liquid. The best,by far, was a powder called " RhizoponAA #3 (.8%). The 3% was ok, but the difference in strength was telling. They were rooting rose cuttings -took 5 wks, which is a long time-hence the #3 (forhardest to root). I usually have my soft cuttings done in 2-3 wks. The powder also came in different strengths -#1 and #2-for easier to root cuttings.
So the next experiment would be to do soft cuttings in all 3 strengths and see what rooted the best lol!
You guys are light years ahead of me on rooting cuttings, but just a reminder: sometimes failed cuttings are the result of soil-born disease. Years ago I had a small, commercial business in miniature roses, and found that rooting was almost perfect with truly sterile soil. Later, with contaminents creepings into my soilless mix, I needed to do a anti-fungal soak or lost everything! Good luck!
Peter...we don't have failed cuttings !!! lol just kidding. Yes, you can always get a fungus if you don't watch yourself. I use a soiless mix that is sterlized-all commercial soiless mixes are supposed to be. The trick is to not get an old shipment.