By Lois Chaplin
Gardeners appreciate growing plants in containers because pots are pretty, and they put the garden practically at our fingertips. In spring, it’s easy to fill pots with plants from a multitude of choices. But what about winter when the cold says, “not so fast”? Keep these tips in mind when preparing a bright spot in the garden for winter.
A container naturally makes many plants more vulnerable to cold because soil and roots freeze more quickly above ground. However, thick concrete and double-walled containers are slower to freeze than thin plastic.
Move prized tender plants such as a hibiscus or citrus indoors. A greenhouse is ideal, but any indoor space with a bright south-facing window works. The idea is to keep the plant alive; it won’t thrive. Expect some leaf drop during the winter, but the plant will recover in spring. Keep the soil only slightly moist. The surface should feel dry between watering.
Always water plants the day before a freeze is predicted. Well-hydrated plants endure the cold better than ones stressed for water.
Wrapping the trunk of a citrus tree (or any potted fruit tree) with tree wrap or strips of heavy brown paper will help protect the graft and keep bark from splitting in extended freezing weather.
When a deep or long-lasting freeze is predicted, gardeners can temporarily group potted plants together and even cover the group with a large frost blanket. Moving them under an overhang or into a corner for radiant heat and wind protection also helps. Putting patio containers on a rolling base makes moving easy, not just in winter but anytime for rearranging and cleanup. For heavy, stationary plants, pile pine straw around and on top of pots to create dead air space that provides insulation. This is only necessary for marginal (aquatic) plants and extreme weather.
A sudden, deep freeze following a period of warm weather is the most damaging to plants because the plants have not hardened off. When the weather plunges 50 degrees overnight, this is especially hard on herbs, vegetables and flowering annuals.
Some popular container plants aren’t usually bothered by cold. Those include hardy evergreen landscape plants such as small conifers, juncus, and evergreen sedges and grasses. These plants can be in containers year-round but don’t offer much seasonality. Punch them up with seasonal color such as pansies.
Keeping pretty pots around for the winter isn’t hard. It just takes selective planting and occasional extra effort on the days winter really bears down.