Book on roses by Douglas Green, Ontario nursery
Gean from PNW recommended this book by Douglas Green, "Tender Roses for Tough Climate". I'm done reading it, and I'm sharing some neat ideas from Mr. Green, who operates a retail nursery in eastern Ontario with more than 2,000 species of plants, including many rose varieties.
He's big on planting grafted roses 6 feet deep for winter-protection. He reported success with manure tea, since he stated, "soilless mixes for pots DO NOT have the micro-nutrients needed ... such as iron, zinc, magnesium, calcium, and copper... water with either a compost tea or a fish food fertilizer on a weekly basis."
He added, "One of our current experiments indicates that a combination of long-term fertilizer pellets applied at half the recommended rates, combined with a compost tea, fish food or soluble nitrogen, also applied at half the recommended rate, produces roses of exceptional vigor and beauty."
Here's his recipe for container mix: "In a wheelbarrow combine 3 cubic feet of peat moss, 1 cubic foot of perlite, 3 teaspoons of superphosphate, 3 tablespoons of lime, and 4 tablespoons of 10-10-10 fertilizer. Mix the lime thoroughly into the peat moss.. By itself, peat moss is too acidic for roses, lime buffers the acid and raises the pH.... mix in well in advance to provide time for lime to "sweeten" the soil... adding sharp sand (coarse sand) at 10% improves drainage."
Tapla, a professor of horticulture, has a recipe of 5-1-1 (five part fine mulch, 1 perlite, and 1 peatmoss) for potting mix. That's the same recipe that Ball, the largest nursery here uses for potting soil, and they also add lime as Mr. Green suggested.
Mr. Green has a useful chart to define what is sun, and what is shade:
1) Shady: 6 am to 10 am - cool sun
2) Full sun: 10 am to 2 pm
3) Full sun: 6 am to 2 pm
4) Warm sun: 2 pm to 6pm - this is partial shade, suitable for roses such as gallicas.
5) Shady: 4 pm to 6 pm - cool sun
Field Roebuck's book "Complete Roses..." has several recipes for potting mix, which includes garden soil for its beneficial soil bacteria and nutrients. Field, a Texan, didn't like peat moss - he included a recipe without peat moss for potting soil.
I visited Ball's nursery here, and was impressed with the abundance of flowering resulting from their potting soil mix, with ingredients (fine mulch, perlite, peat moss, lime) - which is the same as Tapla's recipe in the Fig's Forum.
My question is: Since alkalinity suppresses fungi growth, would putting some lime on the surface of a potting soil decrease fungal diseases such as black spots and rust? Lime sulfur is used in the old days for both rust and mildew - it was discontinued due to safety reasons (very caustic).
Michaelg posted excellent info. on how calcium spray prevents botrytis. My question is: Balling has been reported in potted rose, would adding gypsum to potting mix provide calcium to help with botrytis?