When we have a long, “normal” Canadian winter, it is exciting to work with the first outdoor plants of the season.  This usually happens in April and has in the past comprised of mostly pansies and early perennials.  These are what the horticultural trade calls cold weather plants and they can live and grow in cool, inconsistent temperatures, often below freezing.

Recently we’ve become more aware of choices available in this category, which allows us to now have more creativity in the containers and garden designs we create in Spring.

Cold weather annuals are annual (living only one growing season) plant varieties that perform well, and some even thrive, in cold temps.  These cold temps can occur at either the beginning or end of the season.  An example of such an annual is the pansy.  It is strong, sturdy and full of bloom in the Spring, floppy and non-blooming in the heat of the summer and then, if trimmed of excess growth, strong and lush in the Autumn again when the cool weather blows in again.  Other annuals that do well in cool weather include argyranthemum, alyssum, gazanias, osteopermum, verbena, dianthus, petunias, ivy, bacopa, diascia, and dusty miller.  All cold tolerant annuals can best handle temperatures below zero (to minus two or three) at night when they are well watered in the day. If it is extremely cold, watering off the frost prior to sunrise will eliminate damage to the plant.

Early Perennials (living more than one growing season, bloom and grow from year to year) can be planted in the ground in April, although in the cool ground they may not thrive until the soil is warm later in May or June.  This will also depend on where you live and the sun exposure of the flowerbed.  Some early perennials include: heuchera (coral bells), primroses, columbine, saxifrage, bleeding hearts, iberis, campanula, brunnera, hellebores, ground phlox, dianthus, forsythia and dwarf iris.  Spring flowering bulbs such as tulips, daffodils and the like also fall into this category.

Cold weather annuals and early perennials can be used in combination in your first container combinations of the season.  Lovely combinations can be made with curly willow branches as the height in the centre of a container, hellebores, osteospermum, colourful coral bells and fuzzy dusty miller as the filler plants with alyssum, ivy and pansies spilling over the edges of the pot.  Or consider a simple, petite combo of pansies and ivy with pussy willow branches piercing the middle of the arrangement.

Bleeding Hearts  for early spring gardeningA benefit of using cold weather annuals and early perennials as container plants is that they can be repurposed.  The perennials can be planted in the ground when your Spring arrangements are ready to move on to a Summer look; be sure to remove them gently from the container and water in with a root starter fertilizer to ease the transition.  The annuals can be reused in other arrangements or flower beds or cut back (in the case of pansies, alyssum and diascia that may become overgrown once the heat sets in), planted in partial sun to ride out the summer and brought back into the forefront when the weather cools again in the Autumn.

Don’t get caught up in the excitement of Spring and plant or containerize varieties that are not cold tolerant!  Some stores (not usually your quality local garden centres) will present any or all plants they can as soon as the weather becomes warmer.  In April it is too early, in our area, to have geraniums, begonias, impatiens, potato vines and the like outside in our inconsistent temperatures.  If you get the bug, refer to this guide, or to knowledgeable garden centre staff, for suggestions on cold tolerant plant options.