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Tag: frost

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30 Nov 2009
0 Comments By The Plantscapes Team Plant Care, Uncategorized , , ,

Frozen Ground

CARING for YOUR WINTER GARDEN PART 2

A Frozen Landscape
A Frozen Landscape

It is not necessarily the ice and snow of winter that kills plants.

In fact, snow and ice can act as insulators, protecting plants from wind and sudden temperature drops. More dangerous than the visible signs of winter is something we rarely notice: soggy, poorly drained soil that repeatedly freezes and thaws.

Plants that sit in wet soil can suffer root damage when the ground freezes. Water in the soil turns to ice crystals, injuring and even killing vital root tissue. Hardy plants can recover from dead top growth. Most require nothing more than a hard pruning. But no plant can recover from severe root damage.

How can you prevent the typically soggy Northwest winter from taking a toll on your garden?

It is surprisingly easy. All you need is well drained soil and a layer of mulch.

WELL DRAINED SOIL

How do you turn heavy, Seattle clay into well-drained soil?

  1. Aerate the soil every spring and fall
  2. Add plenty of organic matter

Plants grown in soil rich in organic matter will be healthier, require less water, and usually suffer less insect damage. So what is “organic matter“? Any living thing that you add to your garden is organic matter. As it decomposes, it enriches the soil. Compost, mulch, organic fertizers, minerals, grass clippings, shredded leaves, bark… till it in!

Of course, you won’t turn clay into loam in one season, which is why regular aeration is also important. Aerate and lime your turf areas to improve soil structure. A good organic fertilizer applied in the fall will encourage root growth, rather than top growth. Deep, healthy roots will break up heavy soil.

Never walk on your planting beds, unless you are on a path.

Apply at least a one inch layer of mulch to your flower beds in the fall. Be careful not to press the mulch right up to the stems or to let crater-like pockets form around your plants when the mulch mounds up. You don’t want to trap your plants inside a bowl of freezing water!

Taken together, these steps will pull water down deep into the subsoil where it will not freeze.

This also prevents the phenomena known as “heaving.” As ice forms in the top layer of soil, it expands. This pushes the soil up. If there is a lot of ice, the roots of your plants may be pushed towards – or even above – the surface of the soil. Once again, root damage will kill your garden faster than just the cold.

So remember: the key to winter survival for your garden is a thick layer of organic mulch. Garden bark or compost will protect the soil in the winter and can be turned under in the spring, adding vital organic matter to your garden.

This post was Part 2 of a series.
Part 1: Caring For Your Winter Garden
Part 3: Protect Your Pots

Photo by w.marsh Released under Creative Commons License

28 Nov 2009
0 Comments By The Plantscapes Team Plant Care, Uncategorized , , ,

Caring for Your Winter Garden

Frost covers a Rhododendron
Frost covers a Rhododendron

Winter gardens are common in the Pacific Northwest. Our winters can be so mild that plants seem to grow all year long.

But this is deceptive. Even when we don’t see the heavy and frequent snows of last year, winter poses risks for the garden. In fact, a covering of snow can provide insulation for plants and protect them from freezing.

Frost and sodden ground are the most common plant killers in our region.

The greatest danger to plant survival is a sudden freeze after a warm period. A plant that has not gone dormant has no defenses against winter kill.

We are going to look at ways to protect your outdoor plants and containers from the cold in a series of posts. Today, we’ll talk about frost.

FROST – PRETTY BUT DEADLY

Around Seattle, our first frost usually occurs in early November and our last frost happens in late March. (These dates are only approximate, and there are microclimates all around Puget Sound with different date ranges.) Young, tender plants, growing plants, and new buds are most suceptible to the cold – so you won’t be suprised to learn that the worst frost damage happens to plants in the fall and spring. During the depths of winter, plants are dormant and better able to weather the cold temperatures.

Our almost constant cloud cover throughout the fall and winter helps to moderate temperature swings between day and night and protects our plants. Surprisingly, it is the beautiful clear days, with sunny, blue skies that bring frosty nights.

 There is no way to avoid frost. Even if we could prevent sunny days in winter, we wouldn’t want to! But we can minimize the damage.

  • Frost damages plants by drawing moisture from the leaves to form the ice crystals. Dehydrated plants suffer the most severe injury, so don’t let plants go completely dry during sunny weather.
  • Bare, dry ground loses heat much more quickly than ground covered with mulch. Although our frosts rarely freeze more than the top inch or two of soil, protect your plants’ roots with a good covering of mulch.
  • Do nothing to encourage new growth. Don’t fertilize. Don’t prune plants in the late fall – wait until late spring, when the last killing frost is past.
  • Don’t over-protect your plants. Plants need to be “hardened off” to survive the winter. As temperatures drop and daylength shortens, your plants will slowly go dormant. Don’t interfere with this cycle for cold hardy plants.
  • Container-grown tender perennials can often be over-wintered by placing them in an unheated garage. Remember – you aren’t trying to keep them blooming year round; you just want to protect tender plants from winter kill. Allow them to go dormant, but don’t let the soil dry out completely.

Despite your planning and best efforts, some plants will inevitably suffer frost damage. Sometimes foliage will die back completely. The plant may appear dead, only to push up new growth from the roots in the spring. That is why it is so important to protect the roots from freezing – the topic we will look at next.

This post was Part 1 of a series.
Part 2: Frozen ground
Part 3: Protect Your Pots

Photo by KaCey97007 Released under Creative Commons License