Putting your Garden to Bed for Winter

It’s that time of year… the world is cooling off, leaves are falling or fallen, and thoughts turn to indoor pursuits. Before we can tuck our gardening brains in for a long winter’s nap, however, there are things that must be done.

Preparing a garden for our long, cold Maine winters takes some work, but taking a few extra precautions before the real cold weather starts is well worth it. Pruners, long-bladed shears, and your favorite rake are really all you need to get a garden all cleaned up at the end of the season. Removing old, dead, wet leaf debris and dead stems is essential for preventing disease and pest problems the following year. A cool, moist environment is just what some fungi and bacteria need to thrive, and various borers and other undesirable insects can take refuge in the rotting leaves, and be ready to attack your garden in the spring.

Trimming back perennials and summer-flowering shrubs not only neatens the garden itself, but helps shape your plants for the next growing season. Most perennials can be cut to within an inch or so of the ground; hosta, astilbe, iris, and coneflower are some examples. The exceptions to this are some of the ‘woody perennials’, such as butterfly bush, lavender, and Russian sage. I typically leave these plants whole till spring, and see how far the winter kill has traveled down the stems. Alternatively, cut back these plants to 6-8 inches from the ground and mulch well. Ornamental grasses and other plants with winter interest can also be left till spring. Summer-blooming shrubs like spirea, potentilla, and summersweet can be given a good trim, removing the old flower heads and shaping them. Spring-flowering shrubs should not be pruned at all in the fall, as most have set their flower buds already, and trimming them would remove next spring’s blossoms.

Mulch in the winter is used for much the same purpose as it is in the summer. Mulching is done not necessarily to keep plants ‘warm’ or keep them from freezing, but to keep them frozen and regulate the soil temperature when the weather starts warming up in the spring. The warm days and cold nights that happen in late fall and early spring can encourage plant to break dormancy and start to grow during the day, which then freezes at night. Mulch will keep a plant cold and dormant until the weather warms. Appropriate mulches include bark mulch, straw or hay, cut evergreen boughs, and pine needles. Dry leaves can be used, but care should be taken with these, as they do tend to compact and restrict airflow.

Wrapping your shrubs or spraying them with an anti-transpirant will help plants survive a cold, windy winter, especially evergreens. Burlap is good for wrapping shrubs, as it allows some air to flow through, but will block the majority of cold winter winds. It also protects against deer browsing and sunburn. For newly planted saplings, tree wrap around the trunk will protect new thin bark from sunburn. Anti-transpirants prevent evaporation of moisture from foliage, and are especially useful on rhododendrons and other broadleaf evergreens.

All these steps can help ensure your garden stays beautiful and healthy year after year, even through the harshest of winters. The promise of a bright spring will help us get through the long winter months!