So is this weather bad for our plants?
Although plants can be sensitive to extremes of weather or disease and physical injury, they operate differently than we do.
Most of our plants will be fine for 3 reasons: The right plant is sited in the right place; because plants go dormant in winter; and because they are wearing insulation.
Site: Grow plants that are well suited for our winters and summers. See the USDA cold hardiness map link for an explanation of Zones. Know what kind of sunlight and shade and soil cultures they prosper in. Most importantly, give them good soil with proper pH.
Dormancy: Most shrubs and perennials go dormant in winter which means they slow their rates of metabolisms and have less water content in their cells. They feed little and transpire much less. Many of them lose their vegetation (trees let go of their leaves) or the vegetation is essentially dead (like cone flowers and sedum stalks and iris leaves).So most of the living part is below ground….
which is well insulated. Even though the top few inches of ground is frozen the temperatures deeper are moderate, protecting the root system. A nice layer of mulch will help most of our plants. (There are exceptions e.g., iris don’t need a lot of mulch but borderline zone plants need extra mulch.)
What about the spring flowers? Some shrubs have set blooms for the coming year. The plant itself is already protecting the inner flower with a tight layer of bud scales. The danger isn’t in this cold weather. The danger is when the temperatures warm, the buds start to open, and start sending fluids to the tips of the plant. The bloom is partly open and then we get a freezing spell after the tender flower is exposed. This is when many folks are attentive to covering azaleas and rhododendron buds with sheets in early spring. The late Easter freeze of 2007 is an extreme incident of this weather cycle.
Pansy (Viola × wittrockiana) is an annual for sun to light shade. They like average to rich soil and can benefit from all purpose fertilizer or a little extra Nitrogen. They tolerate cooler temperatures, so in the Southern region they are often put in flower beds in the Autumn to have color through the winter. Here in Nashville they typically survive the winter, and bloom well into May. They tend to suffer from more heat after that.
I’m focusing on these pansies just because they are the most available model right now in the middle of winter and I have some free time to play with my new camera!
So here’s my journal of Winter Flowers ...
Start by taking a glance at my blog from Dec.26. It SEEMED cold then. And that little flower looked great. Pansies were planted around November 1. They always go in a small spot in front of some perennials and a few in this steel sculpture/planter.
Then came early January with many days and nights of bitter cold.
1/4/10 Really cold for days. Highs in 20s, lows in teens or colder.Yeah they are looking puny.
1/08/2010 at 1:30 in the afternoon, light snow. 18 degrees F. Cloudy.
If I had been outside 24/7 for the last week with only a light jacket I would look a lot worse than this.
1/20/10
Warming up, thunderstorms and high 50s.
These yellow flowering pansies are already forming good looking new blooms.They live in the ground just in front of the planter. The blue/purple pansies in the planter are slow to recover. They are suffering because they are in very tight space and didn't get to spread their roots around and because they have no protection (insulation) from the cold.
(Bonus: http://www.webexhibits.org/causesofcolor/17C.html While surfing around sites about pansies, I ended up at this very cool page which illustrates patterns on flowers that only certain insects can see. More questions on the science of plants and gardening…but that’s for another day.)
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