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Busting gardening myths

ONE of my favourite topics to write about involves busting garden myths and there are plenty of myths out there that need clarification. The first summer gardening myth to bust states: "Do not prune trees in the summer or you may weaken them.

ONE of my favourite topics to write about involves busting garden myths and there are plenty of myths out there that need clarification.

The first summer gardening myth to bust states: "Do not prune trees in the summer or you may weaken them." Gardeners who advise not to prune trees in the summer are what I like to call wrong.

Summer is one of the two peak seasons to prune trees in the garden. Summer pruning is called suppression pruning and it is used to control size by removing a percentage of the tree's leaf surface area so the tree cannot expand its growth.

Summer pruned trees should not be pruned in the dormant season because they can get vascular or stem diseases if pruned in the wet cold winter weather. And summer pruning prevents the regrowth of those vigorously straight water-sprouts (incorrectly called suckers).

The specific trees that I recommend pruning in the summer are: Japanese maples, birch, oak, Chinese dogwood, North American and European maples, ash, elm, magnolia and many other deciduous hardwood trees. Fir, pine and cedar may also be pruned during summer but be careful not to expose shaded leaves to full in-

tensity sunlight or the foliage will suffer sunburn. Summer pruning of trees should involve the removal of less than 25 per cent of the total volume of branching on the tree. Removing a larger percentage may harm the tree's sap flow and storage capacity.

Another silly myth states: "Every perennial should be deadheaded to induce more bloom and maintain cleanliness." It is important to understand that many perennials are specifically grown for their seed heads or ornate flower structure. As an example, bear's breeches (Acanthus species) are known to have a very ornate flower structure that lasts well into winter to provide winter interest. And deadheading acanthus does not promote more flowering; it only eliminates the flower's structural interest for the rest of the year. Some perennials such as poppies may send up the odd additional flower after deadheading but the second flush is minor and deadheading poppies, specifically the Welsh poppy (Mecanopsis cambrica) is done to prevent re-seeding. Many perennials are intentionally not deadheaded to promote self-seeding. A case in point is the common foxglove (Digitalis species), mullein (Verbascum species) and the Himalayan blue poppy (Mecanopsis betonicifolia). If those biennials or short-lived perennials are deadheaded you will not get regrowth from the plant's crown or from self-sown seedlings. So you have to let the flower stalks stand to allow the seed to ripen and then collect or scatter the seed onto the ground so it will germinate the following spring. While it is true that many hardy geraniums benefit from deadheading after their first flower flush, not all hardy geraniums will respond by reflowering. So you have to know your plants before you cut them back or deadhead arbitrarily.

Another summer gardening myth states: "Cut the lawn shorter during the summer to promote constantly lush growth and a uniform presentation." Now, personally, I do not care if everyone scalps their lawn down to golf-green height. It only helps to attain my goal of world-wide turf eradication, but I digress. In all fairness to those lawn lovers out there, do not cut your lawn short during the summer. Short cutting predisposes the lawn to brownouts, turf thinning and weed growth. In fact, during the heat of summer in June, July and August, all lawns should be grown longer by raising the height of the wheels on the mower to attain a mowing height of two and a half to three inches in height. Longer grass means deeper root systems, less watering, fewer weeds and no browned-out dead patches.

And the resulting lush green presentation will be the envy of the neighbours as your longer grass withstands the drought better than their short-cropped and lean-looking grass.

Another uninformed myth states: "Always pick up all fallen leaves to prevent the spread of fungal and bacterial diseases." It is true that some leaves can carry spores that may reinfect the parent plant.

However, not all leaves carry disease and in fact, fallen leaves help contribute to healthy worm, beetle and other soil organism populations. If we are not including presentation issues as related to picking up fallen leaves and we are only talking about picking up leaves related to cultural hygiene (disease control) then it is important not to drive yourself insane running around picking up every fallen leaf or paying someone to do the same just to prevent disease infestation. Be sure the plant has a disease before you worry. A good example would be roses, dogwoods, cherries and a few other plants whose leaves can reinfect the parent plant.

As always, a little information grows a long way.

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