Washington State University Extension

Garden Tips

Archive for May 2012


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Let’s be honest when it comes to design some people are naturals. They have an innate eye for color and balance and don’t need to think twice about basic design principles. The same goes for some gardeners who can make the most wonderfully appealing container gardens without blinking. For the rest of us the design process isn’t quite as easy, but there are some simple guidelines that can assist our creativity.

The design lingo in the garden trade is the use of ‘thrillers, spillers, and fillers’ when creating a container garden. ‘Thrillers’ are the taller, vertical element of the design. For years the dracaena ‘spike’ plant was one of the few pot thrillers available. Gardeners now have many more options to add drama to their containers. Proven Winners suggests using annual ornamental grasses, colorful coleus, gaura, or angelonia as thrillers. If a container will only be viewed from one side, thrillers are placed at the back of the container and if viewed from more than one side, they’re placed in the center.

Next you need to find ‘fillers’ that will complement the thriller you’ve selected. Fillers are more compact and rounded plants used to fill in the middle space of the container. They ‘fill up’ the open space and typically have colorful flowers or foliage. With this in mind they’re placed half way between the thriller and the edge of the pot. Depending on the size of the container, often more than one type of filler is used. Some popular fillers include calibrachoa, creeping zinnia, ageratum, salvia, zinnia, nemesia, Marguerite daisies, African daisies, diascia, and non-trailing petunias.

Finally, ‘spillers’ are placed near the edge of the container. These spill or trail over the edge of the pot, softening the edge and making the container garden look more natural and less contrived. Popular fillers include bacopa, trailing petunias, and sweet potato vines. Note that some plants can fulfill dual roles such trailing petunias can be fillers and spillers at the same time.

Using the three elements of thrillers, fillers, and spillers give you the basic structure of your design, but the plants’ scale, colors, textures, and forms need to pleasingly complement or contrast each other.

Here are some color tips from experts at Texas A&M University that might help when selecting flowers:

When it comes to color, the most dramatic combinations are complementary colors, those that are opposite each other on the color wheel, such as orange and blue; red and green; and violet and yellow. The more vibrant the colors, the more striking the display.

Container gardens composed of all one color tend to be more relaxing and soothing. Slightly more dramatic are containers using analogous colors, those that are next to each other on the color wheel, such as yellow, yellow-orange, and orange. If all this is confusing, try going polychromatic and mixing many colors. This usually seems to work too.

Need a color wheel to help you out? Purchase one at a local craft store and take it with you when shopping for your thrillers, fillers, and spillers.

Published: 4/27/2012 10:02 AM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

I like to keep track of what’s ‘in’ and what’s ‘out’ when it comes to garden trends. Each year garden style setters and marketers reveal the newest garden trends. One of the 2012 trends noted by Better Homes and Garden is the use of dwarf shrubs in today’s smaller gardens and landscapes. This has been made possible by plant breeders who have selected and bred more diminutive versions of yesteryear’s large shrubs.

The passe shrubs were too big for today’s smaller homes and yards. The new ‘mini-me’ shrubs are much smaller and typically have a lot more to offer… longer bloom, prettier flowers, interesting leaf color or texture, compact growth, fall color, or fruit. Here’s just a few that I find exciting.

Thirty years ago many area landscapes were planted with ‘dwarf’ mugo pines. Unfortunately, dwarf is a relative term. If a plant species grows to a height of 15 to 20 feet in height like a mugo pine (Pinus mugo), a dwarf mugo pine (Pinus mugo var mugo) that grows 7 to 8 feet tall qualifies as a dwarf. However, most gardeners were probably thinking a ‘dwarf’ would be much smaller.

Today there are select cultivars of mugo pine that better fit a gardener’s idea of dwarf. The Mops mugo pine grows to a height of 3 feet tall and wide and even smaller are Slowmound and Teeny that both reach a height and width of only 1 to 2 feet.

Forsythia is one of those shrubs that never went out of style because of its bright yellow early spring flowers, but it really was too big for most landscapes, making it a candidate for ugly hedge-type pruning. Today, smaller forsythia are much easier to use in landscapes and don’t require much pruning. In my front landscape I have Gold Tide, a smaller forsythia that reaches a height of 3 feet and a width of 4 feet. Last month it was covered with cheery yellow flowers. What a treat! Even smaller is Show Off™ Sugar Baby, a petite forsythia that reaches a height of only 18 to 30 inches and is covered with flowers in the spring.

The flowering quince is another shrub that joyfully announces spring’s arrival. Most older cultivars are on the large side, reaching heights of 4 to 6 feet, plus they have nasty thorns. I dislike thorny plants and refuse to plant them in my landscape. Proven Winners recently released three flowering quince as part of their Double Take™ Storm series. These twiggy quince grow to three to four feet tall and wide and are both thornless and fruitless. I have one of all three, Orange, Scarlet, and Pink Storm. Their gorgeous intensely colored double flowers resemble a camellia.

One little new shrub I hope to add to my landscape this year is a sweet mockorange called Miniature Snowflake. Mockorange is a very old-fashioned shrub not found in most landscapes today because the older forms are large (12


) with leggy, unkempt growth. Their redeeming feature is the delightfully fragrant white flowers produced in early summer. Miniature Snowflake mockorange is a compact, somewhat rounded shrub that grows 2-3 feet tall and wide. While not remarkable the rest of the season, it produces sweetly scented pretty double white flowers in early summer. I plan to place it near my patio so I can enjoy its fragrance whenever I walk out the door.

Visit your favorite local nurseries to find these and other smaller shrubs that you can easily tuck into your landscape.
Published: 4/20/2012 9:53 AM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

I started as a WSU Extension educator on the first day of April in 1980. One of the first calls I received was from a gardener wanting to kill the earthworms in his lawn. Where I came from in New York state earthworms were considered valuable creatures. I wondered if the call was an ‘April Fools’ joke because I hadn’t yet encountered the mounds of soil that nightcrawlers caused in local lawns, making walking across them difficult.

Many have revered earthworms for their recycling of organic matter and building a better soil. Ancient Egyptians declared earthworms to be sacred because of their contributions to agricultural production. While forbidding Egyptian farmers from touching the ‘sacred’ worms might seem silly, USDA research supports that earthworms were critical to the soil fertility of the Nile Valley of ancient Egypt.

Well known natural historian and the father of the theory of evolution, Charles Darwin is not widely known for his earthworm studies. Darwin recognized the value of the earthworm saying, “Without the work of this humble creature, who knows nothing of the benefits he confers upon mankind, agriculture, as we know it, would be very difficult, if not wholly impossible.” His book, ‘The Formation of Vegetable Mould Through the Action of Worms, With Observations on Their Habits,’ published in 1881, was a better seller than his previous book on the origin of the species.

While respected and valued for their soil building efforts, there is now concern that the many of the earthworms that are recycling organic matter in our agricultural fields, gardens, and compost piles are actually non-native species. In fact, research indicates that the worms creating bumps in lawns, being pulled from the ground by birds, and surfacing on sidewalks during wet weather are predominantly non-native species. WSU and University of Idaho researchers checking out earthworm populations in the Palouse area have found that non-native species of earthworms predominate in both home gardens and agricultural lands.

Why the concern? Scientists are worried about non-native earthworms because they’re so ‘good’ at recycling organic matter, maybe a little too good. In the Great Lakes area of the northeast, these over-achieving non-native worms have invaded hardwood forests that don’t depend on earthworms to recycle organic matter on the forest floor.

The invading worms are removing organic matter that would have decomposed more slowly, releasing nutrients and contributing to the growth of native species. The activities of the non-native earthworms have significantly changed the ecosystem and led to an increase in invasive plant species and a decrease in the diversity of wildlife. Studies indicate that the Lumbricus species, including the robust night crawler, are the most destructive.

Some scientists conjecture that earthworms are contributing to global climate change. Yes, really. Current research is studying whether the worms help sequester carbon in the soil with their recycling activities or if they’re actually releasing it into the atmosphere.

Locally, it’s the bumps in the lawn that are a problem. Unfortunately, there are no chemicals recommended for their control. If you have a nightcrawler problem, you can use a dethatching power rake in early spring to break up the mounds by setting the teeth so that they only go deep enough to break up the mounds without tearing up the grass. Because the worms don’t like dry soil, irrigating less frequently and allowing the top couple of inches to dry out may help discourage their mounding activities. I’ve learned that nightcrawlers in the lawn are no joke.
Published: 4/13/2012 9:49 AM



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