In perennial flower beds, the answer for winter protection can lie in any of the organic landscaping mulches, (pine bark mulch, cedar bark mulch, wood chips, pinestraw, hay, straw, etc.). These organic landscaping materials provide a layer of insulation over perennial flower beds that helps protect your borderline-hardy plants from cold.
Snow cover also helps insulate perennial flower beds, but Mother Nature is unreliable. And while plastic-sheet mulch and landscape fabrics will keep weeds down, they don't offer much insulation value. Although organic landscaping materials eventually decompose and have to be replaced, their decomposition also has a positive aspect: nutrients are released, functioning as soil amendments.
The Pros and Cons of Cedar Mulch
I happen to use cedar mulch as an example in the discussion below, because many readers ask about it. Cedar mulch, also called "cedar bark mulch," is one of the most popular choices for use in perennial flower beds.
- Pros
- Long-lasting
- Discourages insects
- Cons
- Since it doesn't break down as readily as some materials, it's not as effective at returning nutrients to the soil
- Some of the insects it discourages may be beneficial
As you can see from this consideration of its pros and cons, our estimation of cedar bark mulch's value depends largely on our personal preferences. Cedar mulch is long-lasting, so it is favored by those who don't want to be bothered with frequent replacement. But this quality is a double-edged sword, since that very longevity means cedar mulch won't replenish the soil with nutrients as quickly as will many other organic landscaping materials. One could also be ambivalent toward cedar mulch's insect-repelling quality: some insects, remember, are beneficial!
Cedar Mulch in Perennial Flower Beds
While cedar bark mulch can be the answer for winter protection in perennial flower beds, be aware that there are right and wrong ways to use it. Incorrect usage may end up doing more harm than good. Follow these tips when applying cedar mulch (or other organic landscaping materials) for winter protection:
- When to apply: Apply cedar mulch after there's been 2-3 days of sustained freezing temperatures.
- How much: Apply 4-5 inches of cedar mulch for winter protection.
- When to remove:In early spring, begin gradually pulling back cedar mulch away from your perennials, so as not to suffocate them.
Note that premature application in fall gives rodents a better chance of making a home under your cedar mulch -- something you clearly don't want. Thus the recommendation to wait for the arrival of freezing temperatures in your area.
Note also that cedar mulch used for winter protection is treated differently than if you were using it summer for weed control. For the latter use, apply 2 to 2.5 inches. But for winter protection, double that thickness (you want the extra insulation).
Cedar mulch and other organic landscaping materials not only keep the ground warmer for plants in winter, but also reduce the chances of frost heaves, which can damage roots. So although there's work involved in using them, the effort is worthwhile. Here's how to prepare the area in need of winter protection:
- Remove weeds and spent annuals
- Remove diseased stems and foliage on perennials.
- But, in general, you can leave healthy stems and foliage on perennials.
- Dig up non-hardy bulbs for storage.
For most perennials, leaving the stems and foliage intact over winter -- assuming they're healthy -- is fine. In fact, doing so can add a little insulation value. In some cases, there's even an aesthetic reason to follow this practice: ornamental grasses, for instance, are often at their showiest in winter.
But perennials plagued with disease or insects should be cut back in fall to reduce the chances of infestation the following season. For example, bee balm and garden phlox have a tendency to be covered with powdery mildew by fall, in which case it's best just to cut them down to ground level.
Non-hardy bulbs, such as cannas, elephant ears and dahlias, should be dug up. Spread out the bulbs to dry in the sun for a few hours before storing them in a cool, dry place (garage, attic).
On Page 4 we'll conclude with some tips on winter lawn care....
