November is the traditional time for that standby of the ornamental garden, the rose, to be at its best. I would have to say that I’m no expert on roses, but I do appreciate their beautiful flowers when they’ve been grown well. And no better place can be found to appreciate them than at a Rose & Flower Show, which is on again this year (for the 95th year!) on Friday November 18, at the Old Masonic Hall, Warkworth from 12noon to 5pm.
Last year I became determined to conquer my lack of skill with this group of plants. Unfortunately, aside from my floriferous carpet roses that are looking gorgeously healthy in huge pots with an abundance of bloom, the other roses have failed to respond accordingly. I suspect a serious loss of leaves last year to black spot has weakened them for this season. I know I can spray for this, but I hate spraying unless I must, not just because kitting up is a pain, but also because I like to use as few chemicals as possible.
However, as I only have a few roses, I only need a small hand sprayer filled with a mix of neem oil, eco-oil (essentially vegetable oil with an emulsifier like detergent) and eco-fungicide (also known as eco-carb; baking soda is an alternative). As these are essentially harmless products, I don’t need to kit up. Applied monthly, or more frequently in spring or in humid weather, this should keep most pests and diseases to a minimal level. Add some seaweed or fish fertiliser to the mix and the roses should thrive.
In fact, this is a good all-purpose spray for most plants in the garden; you may need to dilute it more than the labels says for plants with sensitive leaves, like tomatoes and soft leaved ornamental plants, like ferns. Of course, a backpack sprayer is the way to go for larger gardens and the additional pressure created is useful to get good coverage on both sides of the leaves and penetration into the inside of shrubs or trees. This is important as these sprays are largely contact sprays, that is they need to land on the pest or disease to smother them or disrupt their feeding.
Aside from black spot on roses and apples, this time of year is also the best to control various other serious pests and diseases, such as powdery mildew, mites, passion vine hoppers, potato psyllid and citrus whitefly. Hit them hard with several saturating sprays spaced a fortnight apart from now until Christmas and the rest of the growing season will be much less pestilent!