Microclimates: How to push the boundaries of plant hardiness.

Understanding plant zoning is essential for any gardener, novice and experienced alike. During a visit through one of the many abundant big box stores, I noted several species of perennials that are not cold hardy for our Sudbury winters. Due to the eye catching appeal of such a foreign plant, one has the innate desire to take that unique specimen home for a special spot in the garden. What is not so evident to the aspiring green thumb is that the exotic looking perennial will not be returning from the ground next spring. Once winter brings snow and ice - the expensive purchase is never to be seen again.

Generally speaking, when designing a garden in Sudbury and the surrounding areas, I work with plants & trees with a maximum zone 4 : -34 to -29 C . Zone 3B would be an even safer choice. Zoning is an important factor when selecting perennials and trees, but it is not the only thing that needs to be considered. Soil types, wind, Sun and shade are other key factors that one must also take into account.

But how does one maximize their current zone? One answer is to create a microclimate or identify an existing one in your garden. A brick wall in the sun offers an amplified warm spot for any sun loving, heat loving perennial. A fence, hedge, or thick evergreen can provide shelter from the cold winter winds. A tree, pergola, or arbour will cast enough shade to cool your garden and keep the soil from too quickly drying up. Water can be used in countless ways to create cool spots in the garden. Ammending the soil as well as changing the acidity levels can also greatly affect the growing conditions in a localized area.

See the attached image for zone differentiation.

Click on following link fo more information.
http://sis.agr.gc.ca/cansis/nsdb/climate/hardiness/intro.html