John_fender said:Have you tried to root cuttings of a plant you particularly liked and wanted to cross more with ? Just wondering if its possible to take zinnia cuttings
Hi John,
I don't know of any gardening book that tells how to root zinnia cuttings, but there might be one. There are a lot of gardening books that I haven't read. Many times I have felt the need to take cuttings of a choice zinnia, so that I could have several plants, and use them to get a much greater supply of seeds from it than I could from a single plant. So I embarked on a trial and error process to take cuttings from zinnias.
You can put a branch from a coleus in a glass of water and it will strike roots in the water in a few days. Unfortunately, a zinnia is not a coleus and zinnia roots simply drown and die when submerged in water for an extended period of time.
So I put zinnia cuttings in a sterile growing mix (Premier Pro-Mix BX) and I applied a rooting hormone to the cuttings. Even though the mix was moist, the cuttings wilted and died in a couple of days.
So I repeated that with the addition of a humidity dome to keep the cuttings from drying out. In a few days the cuttings simply rotted. That was not a huge surprise, because bacterial rot has always eventually destroyed my zinnia cut flowers in a vase of water.
So I needed something to kill the bacteria without killing the zinnia cutting. After doing a lot of Internet searching, I found Physan 20. Many greenhouses use Physan 20 to keep things clean and healthy. Some hospitals use it in their mop water. It is a very versatile product, because it is an algaecide, fungicide, bactericide, and virucide. That's a lot of 'cides. I bought a bottle from Amazon.
https://www.amazon.com/dp/B000I2UTAQ/
I needed to find a dose of Physan 20 that would kill the rot-causing bacteria, but not kill the cuttings with a phytotoxic effect. I settled on 1 Tablespoon of Physan 20 per gallon. A little more or a little less would also work. But 4 Tablespoons of Physan 20 per gallon was noticeably phytotoxic. So I made up a stock solution in a gallon jug with a Tablespoon of Physan 20 per gallon, and added a small amount of soluble nutrients. That, with a humidity dome, Pro-Mix medium, and fluorescent lighting provided a successful rooting environment for my zinnia cuttings (which were treated with a bit of rooting hormone). My cuttings consisted of a small branch with the bud removed. They went in pots under humidity domes under fluorescent lighting.
In a little over a week the cuttings had struck roots and could be removed from under the humidity domes and put on a shelf under fluorescent lights.
So you could say that the "secret" to growing zinnias from cuttings is Physan 20. Incidentally, I have carried that a step farther, and taken cuttings from the plants that were grown from cuttings. Those produced plants that originated from a seed planted the previous year. That raised the question in my mind if zinnias might not be potentially immortal via repeated cuttings. Many fancy coleus varieties (and other ornamentals as well) are cultured from year to year asexually, either from cuttings or in some cases by tissue culture.
So, yes, you can grow zinnias from cuttings very successfully, with the help of Physan 20.
ZM (not associated with any product or vendor mentioned or linked)
