By Leslie Cox
Special to the Record
An update from last column: I am pleased to report our Fothergilla gardenii shrub is now showing its fall colours.
John is once again happily photographing the changes in our garden. Thank goodness. There is nothing worse than an unhappy Duke of Compost, let me tell you.
But I cannot blame John for his earlier minor rantings about the shrub. Having to resign oneself to the end of summer and another gardening season is so much easier to endure when the plants are festooned in vibrantly rich colours. Especially when photography is your second passion.
I concur. Autumn is only bearable for its harvest and colour. Grey days and cooling temperatures do nothing for my state of mind or my bones. But walking Sadie through neighbourhoods abundantly planted with assorted maple tree and shrub species is always a joy, no matter the weather.
Forest walks are fun for the leaves from Acer macrophyllum. Their common name, big leaf maple, becomes abundantly clear when you place your foot in the middle of a leaf lying on the path. Can鈥檛 really tell their impressive size when they are 36 metres above your head. (That translates to about 120 feet, if you need the conversion from metric.)
And who can ignore the leaf colours displayed on the native dogwoods right now? The Cornus stolonifera, (red-osier dogwood), shrubs are transforming to a rich russet colour, making them stand out nicely against the neighbouring plants and trees still dressed in green and yellow.
Speaking of yellows, my Acer saccharinum (silverleaf maple) tree is finally reverting to its autumn yellow colour. It is the first of my big trees in the front garden to show life in the spring and the last one to turn colour and shed its leaves in the fall.
Of course, that big wind and rainstorm we had accelerated the timing of the leaf drop a little and now that those maple leaves are littering the lawn and driveway, I can see the extent of the maple bladdergall on them.
With a tree that is upwards of 15 metres (50 feet) tall, the bladdergalls are not too visible, especially since they develop on the upper side鈥� or sunny side of the leaves. However, they do not impact too much on the leaves鈥� photosynthesis process so the health of the tree is not in danger. But the galls are definitely unsightly.
These mushroom-shaped galls are formed by extremely tiny mites 鈥� less than 2 mm, or 0.07 inch in size 鈥� known as Vasates quadripedes. They emerge in spring from their overwintering places in the bark and other crevices on the tree to feed on the swelling leaf buds.
As each adult mite feeds on the developing leaf tissue, they produce certain growth-regulating chemicals which, in turn, interact with certain plant hormones in the leaves to stimulate abnormal cell growth. Hence, an ugly gall develops, which grows large enough to totally encase each ravenous mite where they continue feeding on the inner tissue of the gall 鈥� totally safe and secure from any chance predators and from pesticides.
Eggs are laid inside the gall, the young hatch and feed on the gall tissue and when they reach full adult size, they leave the gall through the underside of the leaf and search for newly developing leaves to start the cycle again. But when the tree has stopped producing new growth, the mites start searching for a suitable overwintering place on the tree trunk.
Unfortunately, the only way to curtail the population of this mite is by handpicking infested leaves. A little difficult given the height of this tree. Thankfully, as with most insect pests, weather and life cycles play a part in somewhat controlling the numbers of this mite.
Leslie Cox co-owns Growing Concern Cottage Garden in Black Creek. Her website is duchessofdirt.ca
