Margaret Lauterbach: A break from winter is nearly ready to open

Tired of gray skies, tan grass and stark landscape? Give your eyes a treat and your spirit a lift at Edwards Greenhouse’s “Pop-Up Park,” grand opening Friday, Jan. 22. It’s free, green grass, colorful flowers, benches on which to sit and absorb loveliness.

Children tired of being pent up by cold weather will find a special play area at the Pop-Up Park, too.

Getting to Edwards Greenhouse is a little more complicated now that the roundabout is under construction at 36th and Hill Road. To avoid delays and a detour, go on State Street to the intersection with Collister Drive, turn north and drive to Hill Road (four-way stop), then turn right and travel east to Edwards Street or Tamarack Drive (they both go to the greenhouse) and turn right again. This is the third year Edwards has brightened our bleak winter with a lovely indoor temporary park. Free, don’t forget.

sweet pea blossoms

If you’ve been in the Treasure Valley for over a year, you know our daytime temperatures rise above 85 degrees as early as May or June. That temperature pretty well spells the end of lovely fragrant sweet pea blossoms.

If you have a good site for them in full sun (next to a trellis or fence, for instance), start sweet peas from seed now. They’re definitely a cool weather crop. Start seeds indoors either between layers of damp paper towels or in pots, preferably 4 inches deep after soaking the seeds overnight or nicking the seed opposite the “eye.”

When possible (that is, the ground is not frozen), dig a trench next to your fence or trellis area, at least 6 inches deep, and fill it with finished compost. You’ll be able to set out sweet pea seedlings in February, getting a start on bloom status. Some folks think those plants’ tendrils take vigor from the plant that could be used for blossoms, so they remove the tendrils, preferring to tie up the vines.

You could also buy started sweet pea plants from Edwards Greenhouse, a traditional grower for that Boise icon.

chill nontropical trees

As winter approaches, falling temperatures pull water out of cells, storing it between cells, ensuring that frozen, sharp ice crystals won’t damage cell walls, but that water loss plus sunshine and drying winds expose above-ground tree parts to desiccation (drying out) that can result in permanent damage to the shrub or tree. Buds and twigs may be killed, bark split and other damage making the tree or shrub more vulnerable to cankers, rot and other threatening disease.

Winter survival depends heavily on the health of the plant as winter approaches. If the plant, shrub or tree has been well watered and nourished, and the variety is appropriate for our area, it should survive in good shape. If it is a drought victim or showing signs of nutrient deprivation by shrunken bark on twigs, discolored leaves, etc., it may be damaged by winter freezes. Generally, mature plants tolerate winter temperatures better than immature plants.

Just as we need sleep to recruit our bodies, nontropical trees require hours of chilling — temperatures below 45 degrees — the number of hours of chilling varying with the species of tree. We’re familiar with chilling requirements of fruit trees, but all nontropical trees need chilling hours.

We usually refer to the winter period in vegetation as “dormancy,” but there are two stages to that dormancy — one is complete rest, during which the plant will not awaken and resume growth under any circumstance; the other is ready-to-go if conditions are right, called quiescence. We don’t see the distinction, but it’s vital for plants. The initial rest period is uninterruptible rest. During this time, the plant can tolerate deep freezes that at other times of the year would just kill it.

In fall, for example, a tree may not be damaged at all by temperatures of minus 30 degrees. That same tree, in early spring, may be awakened, ready to grow after a few days of warmer weather, and then a temperature drop to 10 degrees above zero cause serious damage. The tree has been “dehardened” and made more vulnerable.

This is the opposite of our “hardening off” or acclimatizing tender seedlings by gradually exposing them to direct sunlight and wind.

The longer the cold period beyond the minimum, the readier the plant is to quicken and grow. A few days of warmth in February will cause bud swell on many shrubs and trees. That many days’ warmth in March will cause bud swell and break into blossom or leaf.

This story was originally published January 13, 2016 at 3:04 PM with the headline "Margaret Lauterbach: A break from winter is nearly ready to open."