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Archive for July 2011

OFF WITH THEIR HEADS-DEADHEADING IN THE GARDEN

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

With the recent warm weather there’s hope on the horizon that we will get tomatoes from our gardens this year. My inclination is to just sit out on the patio in the evening, listening to the birds and bees as they finish up foraging for the day. However, there are some chores that are nagging at me even as I relax. I hear a voice calling, “Off with their heads!”

The practice of removing spent flowers or “deadheading” sounds threatening. However, deadheading flowers can lead to a longer period of bloom or even rebloom later in the season for some plants like roses. Rather than spending energy on producing seeds, deadheaded plants can use that energy for flower production and growth.

When visiting my plants in the evening I use my pruning snips to clip off the faded flowers of any perennials or annuals. Not only will deadheading result in more flowers, it gives the garden a neater, well-kept appearance.

Deadheading is especially important for roses. For years, the tried-and-true practice of deadheading roses has involved the removal of a spent rose bloom by cutting the stem at the first five-leaflet leaf, making the cut at a 45 degree angle about one-quarter inch above the leaf. This has been practiced for years, but not everyone feels the five-leaflet cut is critical.

A few years ago I decided that I just didn’t have the time or inclination to deadhead the blooms on my multitude of roses using the five-leaflet cut. I found that a light-duty hedge trimmer worked well for deadheading roses. The re-bloom was better than ever. I think it’s because I was able to get the task done quickly after bloom, encouraging the second bloom to come along. Currently, some rose experts recommend ” nipping off the dead flower just at the neck.” This keeps as much foliage as possible and appears to encourage basal breaks and stronger, faster regrowth.

Many perennial flowers benefit from deadheading including daylily, coreopsis, garden phlox, shasta daisy, coneflowers, salvia, penstemon, rudbeckia, and delphinium, and yarrow. However, some gardeners like to leave some flowers, such as coneflowers and rudbeckia, to provide seeds for birds.

Certain annual flowers, such as zinnia, nasturtium, marigold, dahlia, geranium, and snapdragon, will also perform better when spent flowers are removed. This is usually as simple as using your fingers tips to pinch off blooms as soon as they’ve faded.

Some of the newer varieties of annuals are touted as being “self-cleaning” and don’t require the tedious task of deadheading. The flowers of self-cleaning plants are sterile and tend to drop or blow off the plants once they fade.

Plant breeders figured out that sterile plants, ones that don’t produce seed, don’ t need deadheading to keep them blooming. Seeds tell a plant that it doesn’t need to keep producing more flowers to insure it’s existence. Plants with sterile flowers bloom for longer because there aren’t seeds to signal the plant to stop blooming. Because sterile plants don’t produce seed, more energy goes into flower production. Some hedge and groundcover roses are also self-cleaning.

Cutting off the heads of your flowers may sound violent, but it’s a simple garden practice that translates to more flowers to enjoy when sitting on your patio in the evening.

Published: 7/9/2011 9:35 AM

PERSISTENCE KEY TO CONTROLLING BERMUDA GRASS IN LANDSCAPE

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

I recently heard a group of gardeners talking about the problem of controlling Bermudagrass in landscape beds. Calling it a problem is an understatement. Control of Bermudagrass is a colossal challenge and can’t be achieved easily. Before we talk about control, let’s talk a little about this pernicious grassy invader.

Bermudagrass didn’t come from Bermuda. This low growing, blue-green perennial grass was introduced to this country from southeast Africa in 1751 and has been used both as a forage grass for livestock and as a lawn grass in the warmer regions of the country where cool-season grasses are difficult to grow. In fact, there are cultivated varieties of Bermudagrass that don’t produce seed developed for use in these regions.

In this area, few people purposely plant Bermudagrass lawns, but end up with lawns and landscape beds invaded by this aggressive warm-season grass. Bermudagrass can propagate itself from plentiful seed that develops in late summer. Seeds stay viable in the soil for at least two years.

Bermudagrass also spreads by both tough, wiry rhizomes (root like stems in the soil) and stolons (trailing aboveground stems that can root at base of every leaf or node). Pulling or simple cultivation are not effective ways to control Bermudagrass because pieces of rhizomes or stolons left behind can grow into new plants. However, a persistent program of cultivation and withholding water over an entire season can end in success… if there are no desirable plants in the bed that will suffer from a lack of water and regular cultivation.

Many gardeners use glyphosate (such as Roundup or other brand names) in their attempts to control Bermudagrass. To be effective, glyphosate should be applied when the grass is actively growing in mid-summer. Two to four applications timed three to four weeks apart may be needed for satisfactory control of any regrowth. Perseverance is essential.

The problem with using glyphosate in landscape beds near established trees, shrubs, and perennial is that it’s “non-selective.” If glyphosate is applied to green leaves, stems, or even thin young bark it can enter these desirable plants and cause damage. I have had several plants brought into me this year that were exposed to glyphosate last summer or fall and were showing signs of herbicide injury this spring. Symptoms include stunted, distorted, and narrowed yellowing leaves along with dieback of growth. To avoid this problem, many gardeners will use a shield of cardboard between their desirable plants and the Bermuda grass when applying glyphosate.

Some gardeners have discovered that there are “selective’ herbicides that will kill perennial grasses, including Bermudagrass, but will not harm most non-grasses like trees, shrubs, roses and perennial flowers to which they are applied. The two selective grass herbicides available to home gardeners are sethoxydim ( Monterey Grass Getter) and fluazifop (Ortho Grass B-Gone). They work best in spring when the Bermudagrass runners are 4 to 6 inches long and not drought stressed. Re-treatment will usually be necessary and should be done when the regrowth reaches six inches again throughout the season.

Any of these herbicides are not a one-time “silver bullet” for control of Bermudagrass in landscape beds. Tenacity using both the non-selective glyphosate or the selective grass herbicides will be needed.

Garden Note: Many gardeners now have ornamental grasses in their landscape beds which can be damaged if exposed to these herbicides. Before using any of these products, read and follow the label directions.

Published: 7/2/2011 9:31 AM

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