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| Know what to grow (December 2005) |
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Whether it’s hot or cold, or wet or dry, buy plants that thrive in your climate
By Dale McDonald
This garden is no ordinary garden. No sir. It may be lush and almost impossibly beautiful, but these plants are under intense scrutiny. On judgement day some will make the cut, and some won’t. Jim Klett, a professor in the department of Horticulture and Landscape Architecture at Colorado State University, is the mastermind behind this garden, which has been called one of the most important gardens in America. Its purpose is to help you know what to grow.
“The idea is to evaluate the performance of these annual flowers in the unique and challenging climate we have here in Ft. Collins,” Klett says. “Our growing conditions are characterized by high altitude, intense solar radiation, drying winds, severe hailstorms, large fluctuations between day and night temperatures, and a season-long need for irrigation, yet it’s still warm. Consumers can see for themselves which varieties do best. We recommend the better ones to the growers. We want to help them produce the best flowers for the public to grow in their gardens.”
Judgement Day
August 1st is when judges score all 1,200 varieties. They look for overall growth habits, the number of flowers, and the amount of flowers. They consider disease and insect problems, and how they hold up over the entire growing season. They are rated on a scale from 1 to 10, along with comments like “good uniform growth” or “lack of flowers” or “early signs of yellowing.” For the visually inclined, trial winners (most have photos) are posted on the Internet at www.flowertrials.colostate.edu.
The old adage, "It’s better to be safe than sorry," certainly applies to operating snowthrowers during the winter months. Heavy snows can be dangerous for snowthrower operators if they don’t follow safety advice. "Never attempt to clear a plugged snowthrower while the snow thrower’s engine is running," cautions Peggy Douglas, with the Outdoor Power Equipment Institute. "And never put your hands inside the chute. Generally just below a plug, there are sharp, fast-moving parts."
For the scientifically inclined, the Department of Horticulture and Landscape Architecture publishes a booklet about the trials called Colorado State University Annual Flower Trial Garden. This booklet explains every aspect of cultivation, from how much and what kind of fertilizer was applied, to the soil’s pH, percent organic matter, and amount of zinc. It includes planting dates, dates of severe weather, and how far apart the flowers were planted. For most growers, there’s more information than can be absorbed, so Klett says begin plant selection with the big picture in mind, then get specific.
“When planning a garden the first thing to do is determine an overall objective,” he says. “Then consider the environmental conditions you are going to live with. Sun or shade? Dry, or will you irrigate? Is the soil heavy, or has it been amended? All those things play into the type of plants you can put in the garden. If it’s under a shade tree, you are stuck with shade plants. If the soil is really poor, you may want to use a collection of container plants.”
Make it last
“Ideally, you want a garden that will last through the season. For the early season, put in things like pansies, snap dragons, and dianthus. For summer, you want masses of colors from petunias, geraniums, and verbenas. During late summer and fall, you want the osteospermums, china pinks, and pansies again because they are frost tolerant. There are so many good-performing varieties now that there are many options.”
Klett says choosing All-America Selections is another good way to start. In the 2005 trial garden, the All-America Selections
demonstration garden included 91 varieties.
“An All-America winner is a superior plant that has been judged in trials across the country,” he explains. “We are one of about 30 different trial grounds for them, and I am one of the judges. If it’s a new variety, we compare it to standard varieties already in the trade. It gets scored from 1 to 5 with 5 being the best. What is so good about the designation is that these plants might get a 5 here, and a 1 in Florida. But it takes a high average score to be named an All-America, which means they tend to do well in more locations. That’s good criteria to start with.”
When determining plant selections, it’s important to understand how annual flowers are “typed.” According to Erv Evans, consumer horticulturist at North Carolina State University, general types include hardy annuals, half-hardy annuals, and tender annuals.
Hardy means they are the most cold-tolerant. They can handle a light frost and some freezing weather without being killed. Hardy varieties include calendula, cornflower, foxglove, larkspur, pansy, sweet alyssum, stocks, viola, and many dianthus cultivars. Because they are cold-hardy, they are not heat-tolerant and will die in areas with hot summers.
Half-hardy annuals will tolerate some periods of cold, damp weather but will be damaged by frost. They can be seeded outdoors in early spring and do not need warm soil temperatures in order to germinate. Half-hardy annuals include baby’s breath, bells of Ireland, blue sage, candytuft, celome, forget-me-nots, love-in-a-mist, snow-on-the-mountain, strawflower, and torenia. Most decline in midsummer heat but will re-bloom by fall.
Tender annuals are native to warm areas, are sensitive to cold-soil temperatures, and are easily damaged by frost. When soil temperatures are below 60 degrees, seeds will not germinate very well. Tender annuals include ageratum, balsam, begonia, celosia, coleus, globe amaranth, impatiens, marigold, morning glory, nasturtium, nicotiana, scarlet sage, verbena, vinca, and zinnia.
Considering broad temperature ranges, cool-season annuals such as geraniums, petunias, and snap dragons grow best when daytime temperatures are in the 70s and 80s. Most flower production occurs in spring and fall, and the plants decline during hot summer temperatures. Warm-season annuals such as blue daze, four-o’clocks, and pentas like daytime temperatures in the 80s and 90s, with nighttime temperatures staying in the relatively warm 60s and 70s range.
One trend that is gaining in popularity in warm growing areas is planting warm-season bedding plants such as marigolds and zinnias in August. Traditionally considered summer bloomers following spring planting, they do extremely well moving into fall. A bonus for late-planted zinnias is less trouble with diseases, primarily leaf spot.
Container gardens
“That’s an area that is just exploding,” says Jim Klett. “Everyone can use containers, whether they live in a condominium, townhouse, or apartment. All you need is a balcony, and you can grow flowers or vegetables. Another trend is putting vegetables into flower gardens. Different peppers and eggplants, for example, add texture to traditional flower gardens.
“Gardening is the number one pastime in America, and flowers are continually improving and changing. The array of colors and what’s happening with sun versus shade is just incredible. I never thought I’d see a New Guinea impatiens that would grow in full sun. I’m also amazed by the number of plants that can be reproduced with cuttings. That gives so much diversity, not having to go through seed production. Every year the number of varieties and the diversity surprises me.”
And the winners are ...
Here are some of the big winners at the 2005 Colorado State University Annual Flower Trial Garden. Complete results, with comments, are listed at www.flowertrials.colostate.edu.
Best of Show
Petunia (Mini-spreading) - ‘Supertunia Vista Bubblegum’ from Proven Winners
Best New Variety
Celosia plumosa ‘Fresh Look Orange’ from Benary
Novelty Class
Pepper ‘Black Pearl’ from Pan American
Best Begonia (Wax)
‘Inferno Red’ from Sakata Seed America
Best Geranium (Zonal)
‘Rocky Mountain Salmon Rose’ from Fischer USA
Best Impatiens (New Guinea)
‘Sonic Hot Rose on Gold’ from Fischer USA
Best Petunia (Spreading)
‘Sunray’ from Danziger
Best Verbena
‘Aztec Red Velvet’ from Ball FloraPlant
Best Geranium (Ivy)
‘Glacier White’ from Selecta First Class
Best Impatiens (Mini)
‘Firefly Salmon II’ from Fischer USA
Best Phlox
‘Intensia Lavender Glow’ from Proven Winners
Best Zinnia
‘Profusion Fire’ from Sakata Seed America
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