Roses and their spots of bother | The Canberra Times

Modern gardeners take it for granted that any rose they plant will grow fast, healthily, and bloom in glorious abundance through at least six months of the year. Until last century’s boom in breeding relatively black spot and mildew resistant roses, like the Aussie Lorraine Lee, cottage garden rose bushes were mostly left to ramble up a wall or over a fence, exuberant growers like Parson’s Monthly or Dorothy Perkins, loved for their annual mass of blooms with a few other flowers scattered throughout the year, with their leaf blemishes and winter bare branches carefully ignored, like the wart on Aunt Eugenia’s nose, so familiar you no longer noticed it.

Bush roses were for carefully cultivated gardens, and you didn’t cultivate them unless you were prepared to be most careful indeed, or pay an experienced gardener to do it for you. Garden catalogues of the time advised growing well spaced rose bushes between gravel paths, or with bare soil below them, to reduce humidity and increase the amount of good dry heat reflected up onto the undersides of the leaves. Even now, ‘front fence’ roses grown by a bare footpath, with a bitumen road a few metres off, usually bloom far better than ones in the midst of cottage gardens, given the same amount of food and water. Those roundabouts filled with ‘landscape roses’ are not a miracle of survivability – well, okay, they are, a bit – but roses LIKE the world to be barren around them, and the glare and blare of cars matters not at all, except possibly to reflect off a bit more sunlight.

The more ‘modern’ the rose, the more likely it is to be healthily floriferous surrounded by anything from hollyhocks or kangaroo paw. Sadly few roses, even the most trouble free, can remain black spot free in a year like this, with a summer of rain showers, hot days, cold days, damp days and extremely wet days, and lush growth everywhere.

There are innumerable recipes for stopping black spot spreading on your roses. All of them require work, which is not something most people want to do in a mid-summer heat wave. The easiest recipe is ‘do nothing’. As long as the rose is well established (i.e. has been in the ground and growing steadily for at least three years) black spot probably won’t kill it, just give it the equivalent of a mild case of teenage acne. But if you have a just-planted rose you absolutely adore, it can lose nearly all its leaves and bloom to black spot, and may even die back.

This is when you need to spray. In my early gardening days, before I realised that wallabies will inevitably eat every rose I grow here unless it will comfortably grow over two metres high and out of range of their questing paws, I used a spray I’d invented: 1 teaspoon bicarbonate of soda mixed into 1 cup of milk and 3 cups water, sprayed every three days for a fortnight, both under and on top of leaves. This invention was based on the assumption that the alkalinity would be inhospitable to black spot spores, and that the light oil covering from the milk would inhibit their germination, but not be thick enough for sunlight to burn the rose leaves. A few years after that the Rose Society of the USA recommended mixing three teaspoons bicarbonate of soda with 2.5 tbs PestOil (a commercial oil-based spray) then mix into 4.5 litres of water. Spray every four days for two weeks then once a week. The Hume Council guarded their rose collection with a mix of 2 litres of full-cream milk,1/2 litre of dishwashing liquid and 1/4 cup of vegetable oil, sprayed every 10 days on top of the leaves and under them.

I’m not sure of the wisdom of spraying so much oil and especially washing up liquid on roses, or rather, having it drip onto the soil below them. The microorganisms in soil – not to mention the larger creatures like earthworms and various larvae – did not evolve to co-exist with regular doses of dishwashing liquid. Even regular deposits of milk can kill the grass and I don’t know what else underneath it. If a plant needs regular spraying, you are growing the wrong plant, or, just possibly, worrying too much about small blemishes, like a bride with a wayward hair in her eyebrows.

The best defence against black spot is to cover the soil below with a lucerne mulch to stop soil-born spores splashing up; to spray weekly with a seaweed fertiliser, partly because it might (emphatically only ‘might’) make the leaves more black spot resistant, but will definitely be good for the overall growth of the bush. Scatter a little fertiliser every fortnight on top of the mulch till autumn, and water the mulch, not the leaves, when you water in the fertiliser. Prune roses back in mid-summer( i.e. now) too. New growth is more black spot resistant, and pruning and feeding stimulates new growth. New growth will also hopefully lead to a flush of flowers so brilliant you won’t notice a few shadows on the leaves. Then in winter strip off all dead roses and faded leaves, spray with Bordeaux spray, and mulch again.

There are also commercial sprays, but as I’ve never used them I can’t comment on their virtues or possible side effects, if any. If possible, just learn to love a not-quite-perfect rose bush. As a last resort, of course you can just leave the problem for the possums or wallabies to sort out. They’ll get rid of all the black spot on your roses. You won’t even have to pick the flowers, either.

• Still waiting for the first ripe cob of corn.
• Deciding to definitely weed the areas where I want to plant next month’s autumn peas, winter carrots, broccoli, broccolini and red cabbage … just as soon as we have a few cool days to cool off not just the air but the soil my face will be hovering over.
• Glorying in a hundred or so blue and white agapanthus blooms, all of them newish non-invasive species that don’t spread seedlings, but which have multiplied enough to begin thinning the clumps this winter into a few ‘impossible to grow anything else’ patches.
• Delighting almost as much in the miniature agapanthus which have grown no more than 20cm high, and are throwing out spray after spray of blooms. I didn’t quite believe a fairy-like aggie could exist, but they do. I may even break my ‘no more flowers’ policy and buy some more this winter.
• Buying various species of local native grass seeds, which may not be of interest to the home gardener, but as we have large bare patches now that became colonised with weeds after the last bushfire summer, it will be fascinating to see which native grasses grow best in various seasons, and how the fauna respond to the new flora, too.
• Beginning to long for winter’s harvests, which aren’t as sudden, prolific and urgent to pick as summer’s. Bring on the kiwi fruit, the winter pears, the Lady Williams apples…

This is an idea rather than a recipe, and can be modified indefinitely. The aim to have a cake you can slice, with the maximum of colour and no fat whatsoever.

A cake tin or large bowl, lined with plastic or silicone wrap, or with nothing at all if you have a little confidence.

Enough fresh fruit to fill the tin when pressed lightly, say, chopped watermelon, rockmelon, blueberries, raspberries (both can be frozen) chopped plums, chopped peaches, whole strawberries, or not squishy segments of mango. All fruit needs to be firm enough for a knife to slice it easily when the ‘cake’ is cut. Avoid pineapple – it’s hard to cut and raw pineapple may prevent the jelly setting. You can have a single fruit, or layers of fruit, which looks the most spectacular, or a fruit salad, with chopped mint too if you wish.

At least two cups of jelly, slightly more than you will need to fill the crevices, set with gelatine or a vegan alternative according to directions on the packet. Use about a quarter more setting agent than advised.

For adults, perhaps a cup-and-a-half of champagne or rose mixed with a half a cup of sweetened-to-taste hot water to mix with the setting agent. Port with a little cinnamon added to the hot water mix is luxurious. Add more or less sugar depending on the sweetness of the fruit.

For kids, try a cup-and-a-half of blueberry juice for a very red jelly, mixed with half a cup of water and setting agent, or a packaged jelly of the kind you prefer.

Fill the tin or bowl with fruit then pour in the jelly mix. Make sure it comes right to the top of the brim. Leave overnight in the fridge to set.

Turn it out. If the tin or bowl is unlined turn it upside down with a plate at the ready to catch the jelly, then pour very hot water over for a few seconds, place the plate underneath as soon as you stop pouring water, then let the jelly detach itself onto the plate.

Decorate with more fresh berries, or whipped mascarpone and grated dark chocolate of you want to gild the lily.