Regional Gardening: Cold Zones

People living in more northern climates are faced with their own unique challenges just as we in the South are. [See: Gardening Problems in the South.] The summers tend to be shorter and the winters longer. In addition, both are usually both cooler than the summers and the winters in the South. This means that certain plants that thrive in the South cannot even be grown in the North or can only be grown as annuals instead of as perennials. Gardening also requires that Northerners use slightly different methods than we do in the South. [For information on gardening in warmer climates, see: Regional Gardening: Hot Zones.]

Cool summers
The summers tend to be cooler the further north you travel. Northern gardeners, therefore, need to allow the ground to warm up before applying their spring mulch. This also means that the growing season is probably a bit shorter than in the South with spring-blooming flowers frequently blooming right along with those that bloom in the summer. Ironically enough, even though the actual growing season may be shorter, flowers may bloom longer in regions with cooler summers. (The blooms are not being baked by the hot sun we have in the South.)

Early frosts
Often frost may come early to more northern climates. Fall plants should be chosen that bloom earlier in the fall. Plants that might be particularly sensitive to a surprise early frost should be planted in protected areas; e.g., on a hillside or slope or along a south-facing wall.

Cold, frigid winters
The winters are definitely colder in the North, which means that northern gardens really should pay attention to the USDA Plant Hardiness Zone map. If a plant is only hardy to Zone 5, for example, you probably will not want to try to grow it in Zone 3. (Most gardeners, however, do push the limits place by this map. See my article on the Japanese Aralia. Prepare yourself for a dead plant, though. You can also pat yourself on the back if a plant does survive outside its comfort zone. I would recommend, though, that you not spend a lot of money on a plant that might not survive in your particular zone.)

Plants should be situated in the northern garden in such a way as to protect them from cold, drying winter winds. Northern gardeners should also stop fertilizing their plants in the late summer as the plants are preparing to go dormant. In addition, plants should be well-mulched after the ground has frozen. Winter temperatures tend to fluctuate, with freezing and thawing and then freezing again being common. Mulch is actually applied in the fall/winter to help keep the ground cold and at a more constant temperature during the winter, which helps to prevent heaving caused by the changing temperatures. Leaves and pine boughs can also be added on top of the mulch for added protection.

Snow
Snow helps to insulate the ground during the winter and provides added protection for your plants during the colder months. In addition, snow provides much-needed moisture, which your plants will appreciate when spring finally does arrive and plants begin to send forth new growth.

Late frosts
It is not uncommon for northern regions to experience late frosts in the spring. Even in my Zone 6 region of the south, we realize that frosts can take our plants as late as May. (A rule of thumb in my area is to not plant anything until after Mother's Day.) Frosts might come even later in the spring the further north you live. This means that you should not remove mulch too soon in the spring and not be too eager to plant new things. Familiarize yourself with the weather patterns in your region and talk to experienced gardeners about a good planting time.

Every region has its own unique conditions. Learning about these conditions and the best ways in which to deal with them will help you to be a more successful gardener.

References:
Hodgson, Larry. Perennials for Every Purpose. Emmaus, PA: Rodale Organic Gardening Books, 2000, p. 18.