Making Miniature Cuttings
About three years ago I had my first experience in making cuttings the primitive way under a clear plastic tent. A local wholesale rose grower told me in the fall that they would like to introduce my first miniature rose 'Rubies'n'Pearls' the following year; however their mist propagation is shut down from October to February and all I had was four plants of it. My growing lights in my basement are not in use until Jan/Feb when my new seedlings are coming up. I then placed those 4 plants of 'Rubies'n'Pearls' under my lights at the end of October. By the end of November I took my first cuttings.
I use 11"x 14"x 5" Rubbermaid dishpans into which 20 small 2 1/4 pots fit nicely. I used bamboo skewer sticks to hold up the clear plastic cover and lowered my fluorescent to 2-3 " above the cover. I made my own soil mix of perlite and peatmoss. Sometimes I would leave the cover on for several days before checking and misting the leaves. When I opened it, I found that many leaves had fallen off and some of the skewer sticks had started to get mouldy. About 60 % of the cuttings would root for me, therefore I thought I was doing OK since the first roots on these were growing out of the drainage holes after 21-24 days. Even with the 40 % loss rate, I still managed to have 55 plants by March/April. From Nov. 1994 to Feb. 1995 I tried the same thing over again (but changed some of my methods) with my latest introduction, the mini 'Golden Beryl'.
I now work with a local retail miniature nursery. His mist propagation is also shut down from Oct. to February. Three Canadian and one US mini growers liked 'Golden Beryl' very much and wanted plants for their own propagation and 1995 introduction. We only had about 6 plants of this rose and were only able to get 12-15 new cuttings in September. However I needed more plants for the other nurseries and I wanted a few dozen plants for myself. By mid-October I took 4, four week old cuttings, plus one mature plant into the basement under the lights. About Nov. 20th, I was able to take 15 cuttings from the mature plant and another 15 from the 2 month old cuttings. By the end of Dec., I managed to get another 40 cuttings: 10 from the mature plant (which was then taken outside to go dormant) and 1-2 from each of the 'second cut' 6 week old cuttings. During January, 1995, all 70 cuttings were growing so well, that by early February I increased my new cuttings to 150. The local mini grower now had his mist propagation system up and going again so I transferred these cuttings to him since I needed to give my time and bench space to my bumper crop of 4000+ new seedlings!. If I had kept going on, I probably could have doubled the number of cuttings by April.
My biggest surprise was that I did not lose a single cutting of those
150, and lost about 3 leaves. They were also rooting much faster, coming
through the drain holes in only 12-15 days. I should point out that I
have learned a lot from Brad Jalbert, the owner of "Select Roses" nursery,
the local mini grower with whom I am contracting to propagate my roses.
He is always getting 99-100 % rooted, unless the outside temperature is
close to 80º F., but then he stops making new cuttings.
1. I am now using a special, ready made, commercial planting mix which comes in bales like peat moss. I believe this mix has made the difference in getting 100 % rooted cuttings. It is called " Sunshine Mix Aggregate Plus #4 ". It's major components are Canadian Sphagnum Peat Moss, Perlite, Dolomite Limestone (pH adjuster) and a wetting agent. In Canada it is made by "Fisons Horticulture Inc." and in the US by "Sun Gro Horticulture Inc." [Web site: www.SunGro.com]. My damp-off losses are way, way down to only 2-3 %, some varieties 0 %, since I now use only this mix for all my seed germination and for potting up my seedlings.
2. Since the temperature in my basement is only 60º- 65º F., I felt that some bottom heat may help foster better, faster rooting. For each dish pan, I made a wooden stand 6" high with 2" open on bottom of front only. I mounted a 15 watt light bulb 2" below the bottom of each dish pan. If temperature inside the propagating tent went higher than 74º-75º F. I changed over to a 7 1/2 watt light bulb as ideal temperature is 70º-74º F. max.
3. I have placed thin boards as spacers so the bottom of the pots are raised about 1" above the bottom of the dish pan. I keep the hollow space below filled with about 1/2" water which is constantly evaporating and dripping down again from the clear plastic cover. It was not evaporating that much without the bottom heat.
4. I am now using plastic sticks to hold up the clear plastic cover instead of wood skewers, which got mouldy.
5. Three more tips from the local mini grower:
Update-May 8 th, 1995,
My results: Every cutting rooted! Some took only 12 days, and others took 21-24 days until the new roots came through the drainage holes. All are growing in bigger pots now with some already having basal breaks. With 30 grow lights on 16 hours a day, my basement temperature comes close to 80º F.; therefore, by mid April, I turned the bottom heat (now a 7 1/2 watt bulb) off completely. My 100 % success rate with untried varieties of minis proves again that my method of rooting cuttings can be used almost at any time of the year, except I think, when the temperature goes well above 80º F.
by George Mander
(first published in the Rose Hybridizer's Association newsletter in summer 1995)