Plant Hypochondria, Maladies without long-term consequences
You may think that you have an incurable disease in your well-tended garden, but don’t become preoccupied, as most are not life-limiting. We often assume the worst, and wonder if browning leaves are a sign of a permanent problem.
When it comes to our own health, we tend to manufacture all sorts of ailments when we can’t explain a particular symptom, until a doctor puts our mind at rest. There are many conditions that a plant may get, but it might just be a cosmetic concern.
As we hunker down for a four month break from outdoor gardening, otherwise known as winter, we can rest assured that nature has a way of taking care of itself.
In recent years, an alarming number of gardeners have noticed black ink stains on the leaves of their maples. Chances are they’re varieties that have originated from Norway. As unattractive as it is, this malady is harmless. The spores of maple blotch are airborne, so whether you compost your leaves, or not, it doesn’t make a difference. To avoid the problem, we recommend that you plant Sugar Maples. These are native trees that, like the Paper Birch, are not susceptible.
The mighty Oak
If there is a giant survivor of the native forest, it would surely be the oak. The white, pin, red and burr oak trees are incredibly strong and live for a very long time. They are a source of pride to many a homeowner, and a source of frustration to many perfectionists. Oak trees attract all kinds of insects, and more-than-afew diseases. Aphids, mites, miners, mould, mildew and cankers – you name it, and chances are the oak will attract it. However, oaks generally pull through, quite nicely, no matter the contagious pathogen that they are exposed to.
There are certain apple trees (including crab apple) that attract black spot and apple scab on their leaves like it’s nobody’s business. Gardening professionals (like us) will tell you to spray them in the spring with the all-natural Green Earth dormant spray, in order to help minimize this problem. The truth is, some varieties of apples, and crab apples, are naturally susceptible to these common diseases. And, if the weather conditions in late spring and early summer are just right (cool and wet), there isn’t a darn thing that you can do to prevent the problem.
We have approximately 15 crab apple trees that line our property along the road. Most years, they are leafless by late July. And, just as reliably, we can expect to see a profusion of blossoms each spring, followed by shiny new leaves. It’s a cycle that thrills, and depresses, us each year.
Other plants that suffer from assorted maladies, which don’t have continual effects, include mildew on roses, rust on hollyhocks, slugs on hostas and, for that matter, clover in the lawn. Some people remove clover from their lawn, and others sow it so that they don’t have to cut it so often. The hope is that these two people don’t move in next door to each other.
If you have disease-ridden varieties in your garden, chances are that they’re otherwise healthy – just not healthy looking. When planting, consult with your local retailer or garden designer, and try to choose disease-resistant varieties.
Mark Cullen is a Member of the Order of Canada, and provides gardening advice to more than two million Canadians each week. Ben Cullen’s specialty is food gardening. markcullen.com; Facebook @MarkCullenGardening and Pinterest @MarkCullenGardening.