Regional Gardening Reports :: National Gardening Association

In the Garden:
Pacific Northwest
September, 2004
Regional Report

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Daylilies are the stars of my summer garden with their mildly fragrant, sunburst-hued flowers.

Planning For All Seasons

My perennial garden has three high points; the early bulb display, the fleeting but lovely period in late spring when the peonies, iris, and rhododendrons bloom, and the flamboyant months of July and August when the daylilies strut their stuff.

The garden changes gears as fall approaches, and I'm never quite ready to relinquish the lively and energetic summer display my flower beds provide. One sure way to keep the garden interesting is to replace summer-blooming annuals with those that bloom best in cooler weather.

Favorite Cool-Season Flowers
Pansies (Viola wittrockiana, V. tricolor hortensis) bloom in a wide variety of colors from fall through winter. If planted in rich, well-draining soil, they will overwinter and provide excellent spring color just when the first bulbs are starting to emerge.

Pansies should be planted in early fall or at least one month before the first hard frost to allow enough time for the roots to become established. Pansies usually grow to 8 inches in height with flowers of 2 to 4 inches, depending on the strain. Smaller-flowered varieties seem to tolerate cold temperatures best, but all will thrive in cool fall temperatures.

Violas (Viola cornuta, V. tricolor) have smaller flowers and grow taller than pansies. They are more heat tolerant than pansies and can be enjoyed well into spring and summer if you trim them back after their first bloom or when they become leggy.

Also known as pot marigolds, calendulas (Calendula officinalis) bloom in bright orange and yellow from late fall into winter. Reaching heights of 1 to 2 feet with flowers up to 3 inches across, they provide bright color in full sun until temperatures drop below 25 degrees F.

In protected areas they will continue to bloom into spring if spent blossoms are removed. The taller-stemmed varieties make excellent cut flowers and can even be dried. The petals are edible and can be added to salads or sprinkled onto soups.

Dianthus are known commonly as pinks because the edges of the flowers seem to have been trimmed by pinking shears. There are over 300 species of dianthus, most of which are low growing (6 to 8 inches), although some reach heights of up to 3 feet. These plants enjoy full sun and produce white, pink, red, yellow, and even violet flowers with a spicy fragrance.

Sweet William (Dianthus barbatus) is the cottage garden standard, reaching 10 to 20 inches with dense clusters of half-inch flowers. Chinese pinks (d. chinensis) are more compact plants and have larger flowers.

Snapdragons (Antirrhinum majus) planted in early fall will reach bud stage before night temperatures fall below 50 degrees F. They will continue to bloom through winter and into spring. Feed and water regularly to produce the most blooms, but avoid overhead watering as they are prone to rust. There are numerous cultivars. Tall varieties (2-1/2 to 3 feet) include 'Rocket' and 'Topper'; intermediate varieties (12 to 20 inches) include 'Liberty' and 'Sprite'; and dwarf varieties (6 to 8 inches) include 'Magic Carpet' and 'Floral Carpet'.

Non-Flowering, Cool-Season Favorites
The highly ruffled foliage and striking color combinations found in ornamental cabbage and kale make them focal points wherever they are planted. Leaves of pink, rose, lavender, purple, or cream are edged with green or blue-green ruffles. Both kale and cabbage have a similar appearance, but kale has looser and more highly ruffled leaves. The first frost intensifies the colors, and all varieties are edible.

Ornamental grasses come in shades of blue, red, and green, and they range in height from less than 12 inches to more than 10 feet. They're nearly insect and disease free, and they tolerate a wide range of soil and temperature conditions. To top it off, they need little care to look great.

Cool-season types grow in the cool, moist weather of spring (or winter in our mild-winter climate). They flower from late winter to early summer, and then grow very slowly, if at all, in summer. Their growth resumes once fall arrives. These grasses offer early-spring appeal and in many cases their foliage is evergreen over the winter season.

Blue oat grass (Helictotrichon sempervirens) and Northern sea oats (Chasmanthium latifolium) are two of my favorite cool-season grasses. Blue oat grass is a ground cover-type plant with a mounded shape, reaching 2 to 3 feet tall and wide at maturity. Grow this plant in full sun and well-draining soil and you'll be able to enjoy the signature blue hues of its foliage to the fullest.

Northern sea oats grows 24 to 36 inches high in loose clumps of green foliage. Its name derives from its seedpods, which look like oats. This deer-resistant, ornamental grass is cold hardy, but even after its leaves have dried and died, this grass provides visual interest to the winter landscape.

Lemon grass (Cymbopogon citrates) is a clump-former, with a pleasing, rounded, graceful habit. It never flowers in our region; I grow it for the deliciously lemon-scented leaves it produces almost all year-round.

As you can see, there is no reason for the garden to become a dead zone when the temperatures cool. Experiment with these late-season bloomers and see how much more you'll enjoy your garden during autumn and into the winter months.

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