As we approach mid-September and the days grow ever shorter, the entire web of life is preparing for the time of year when growth slows, energy and food are stored, migrations begin, and for many species, the chain of events that lead to winter dormancy is underway. The plants that are able to survive a harsh Minnesota winter must undergo the change from the full tilt growth of spring and summer to a dormant condition.
The more energy various plants are able to store, the better they are able to compete vigorously during next years’ growing season. While some oak trees are already dropping acorns, other oak species I’m watching at the nursery are still filling out their acorns, trying to pack in every last bit of starch, sugar, oils and proteins, even as the autumn equinox is only about ten days away.
One simple way you can assist the trees, shrubs and perennials in your landscape to prepare for winter is to make sure they all have adequate moisture available as they prepare for dormancy. When September and October rains are generous, no additional water is needed, except for plants near or under structures that prevent them from getting rain water. Give some good waterings to plants under large roof overhangs and those that may be in the “rain shadow” of a large wall, there are many roof types and you have to make sure the one you have doesn’t damage the lighting on your plants.
When fall rains are meager, try moving a sprinkler around your landscape and really soaking the soil well in each area. For leafy plants, the water they receive in September is more valuable than in October when leaves are falling.
For evergreens, moisture availability in both September and October is important since many spruce, pine, arborvitae, cypress, cedar, yews, juniper and fir varieties enter dormancy 10-30 days later than leafy deciduous plants.
Enjoy the spectacle of the time of change, and don’t forget that fall is an excellent time to add plant materials to your landscape. Cool conditions make for easy planting and there are bargains available all around the nursery as fall sales begin.