by Bruce Gillett, MD
“More exquisite than any other is the autumn rose”
Theodore Agrippa d’Aubigne (1552-1630)
Autumn is a great time to enjoy the Rose Garden at Smith-Gilbert Gardens as well as your roses at home. You planted, pruned, sprayed, fertilized, watered, and deadheaded. Now you deserve to meander in your rose garden enjoying the cooler mornings. During this season rose flower color is more intense and flower form lasts longer. After the morning sunshine has warmed the oils of fragrance, make the time to smell the roses and watch the hummingbirds flit from blossom to blossom.
Autumn is the time to assess how the roses performed. Which plants thrived, which were stunted, which bloomed poorly, and which were ravaged by disease and insects? Location… location… location is often the answer to some of the questions. Did your roses receive six hours of sunlight? If not, consider planting more shade tolerant roses such as Hybrid Musk cultivars; or plant your roses in containers and place them in a sunny area.
Does your rose garden soil have the right composition – 1/3 clay, 1/3 coarse sand and 1/3 organic material? Does the soil drain properly? Check soil water drainage with a coffee can. Cut out the bottom, push the can one inch deep into the soil and fill the can with water; it should completely drain within one hour. Did your roses receive four gallons of water each week if there was not at least one inch of rain during the week? Were your roses protected with three inch layer of mulch? Autumn is a good time to obtain a soil test to determine the level of macro and micro nutrients, but most importantly to check the pH. A pH of 6.5 is ideal for roses. Roses are not able to utilize nutrients if the soil is too acidic or too alkaline. Normal decomposition of organic material and sulfate found in most nitrogen based fertilizers acidify the soil. Use dolomitic lime to raise the pH.
Did you spray fungicides every two weeks and mix a contact fungicide with a systemic fungicide? Did you use two or three systemic fungicides, each with a different mode of action, to prevent fungal resistance? Did you practice good sanitation technique by removing fungal infected leaves from the plant and the ground?
Fertilize for the last time at the beginning of September with organic fertilizers. Add three cups of alfalfa meal; it contains triacontanol, a growth stimulator. Fertilize with a liquid concentrate at the end of September to boost those fall blooms. Continue to spray fungicides through October. In November spray Lime-Sulfur and in December spray dormant oil.
The roses in the Rose Garden at Smith-Gilbert Gardens get much tender loving care from Cobb Master Gardeners. We and the staff of Smith-Gilbert Gardens hope you will come and enjoy the beauty and fragrance in the Rose Garden.