Wake up your garden! | Ottawa Start

7 • POSTED ON March 01, 2005
Wake up your garden!
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Welcome back to “Start Gardening”, Ottawa Start’s very own green hangout on the web. Albeit somewhat early to run outside to perform miracles in your green oasis, starting today we will gear you up for another exciting gardening season. We’ll begin with some theory, but once spring arrives we will show you how to take proper care of your green space.

Welcome back to "Start Gardening”, Ottawa Start's very own green hangout on the web! (Published every Tuesday from March to December.)

Albeit somewhat early to run outside to perform miracles in your green oasis, starting today we will gear you up for another exciting gardening season. We"ll begin with some theory, but once spring arrives we will show you how to take proper care of your green space!

Plant dormancy

The fact that plants go through a dormant state during the winter is something we take for granted. We all know - and expect – plants to die down in the fall to protect themselves from the harsh winter weather and that – with any luck – they emerge again once spring arrives to warm up the soil. However, as is often the case when Mother Nature is involved, there is more to it than meets the eye…

Dormancy is a complex phenomenon that is present in most forms of life, including seeds, bulbs, tubers, perennials, shrubs and trees. It is generally characterized by a unique physiological and metabolic state that results in a lack of further development and growth. Basically, dormancy is a device by which organisms survive long periods of adverse conditions. By the same principle, certain mammals hibernate to avoid winter with its lack of food.

As always, unraveling the physiological processes that control seed germination, flower production, fruit set and seed production, was a long and painstaking process. Our knowledge of these processes is largely owed to horticulturists who have been studying the topic since the early 1900’s. Understanding plant dormancy and temperature requirements is – of course – of huge importance to those who professionally grow either edible or ornamental plants.

A major discovery was that that many plants require a period of low temperatures before being exposed to warmer temperatures in order to break dormancy or to flower (this process is known as stratification). A simple example of this can be found in plants that we know as “biennials”. When grown from seed, plants such as foxgloves or parsley will form a rosette of leaves at ground level the first season. It isn’t until after their first winter that they will develop elongated stems that eventually bear flowers. The same principle applies to most spring-flowering bulbs. Even though the flower is already formed in a dormant bulb, it needs low temperatures to overcome its dormancy and initiate the lengthening of its flower stem.

Here’s a little trivia for you to help you understand why studying this topic was – and is – so incredibly important. In the 1920’s, Russian scientist Trofim Lysenko subjected winter wheat seeds to extreme low temperatures so that they could be sown as a spring crop rather than as a winter crop. This greatly reduced the amount of wheat seeds lost to hungry birds in the winter, thus improving the size of the crop that could be harvested and preventing mass starvation.

Unfortunately, after this discovery Lysenko became slightly overwhelmed with his own success. Named President of the Soviet Academy of Agricultural Services in 1938, he became a Stalinist deputy for science and began persecuting colleagues who did not agree with his theories. He is believed to have been responsible for the exile, torture and death of many a talented scientist, thereby creating an environment of oppression and backwardness in Soviet science. Anyway, enough trivia for one column, let’s get back to reality.

A topic like the one we are tackling today is tricky to explain without becoming too technical. I could tell you that dormancy can be subdivided into three categories: ecodormancy-arrest, paradormancy-arrest and endodormancy-arrest, but somehow I don’t think that towards the end of the column I would have many readers left if I were to follow that tack. Suffice it to say that all three dormancy categories have one thing in common; somehow growth is prevented in situations where otherwise growth would occur. Although we are still not 100% sure what exactly controls this process, it is now commonly accepted that a blockage of cell growth occurs as a result of an interaction between the signaling pathways controlling dormancy (light, temperatures etc.) and those controlling the cell cycle.

Next time we will look into why certain plants do and certain plants don’t survive the winter, even if they are supposedly hardy.

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About René
René Trim was educated and trained in The Netherlands, before moving to Canada in 2000. After studying the differences in climate and season faced by Ontario gardeners he established Trim Garden Design and Rescue in May 2002. A gardener since the 1980’s, he has a wealth of knowledge and experience, a vast library of reference materials from which to draw answers to various garden situations as well as an enthusiastic and professional staff.