By Urban Harvest
Gardeners across the city are looking forward to the cooler fall temperatures and eager to get summer's tired annuals out of the garden.
The cool season color parade of pansies, snapdragons and alyssum, to name a few, has reached nurseries across town. Prepare for the arrival in your garden with a little groundwork.
Get your beds ready by feeding your soil so it will feed your annuals from the moment you plant. Fork in organic matter in the form of compost or shredded hardwood mulch along with a good organic fertilizer and bed amendments.
While not all soils are the same and some may require specific nutrients, a basic bed prep recipe for 100 square feet planting bed includes 1.25 cubic yards of compost (save a fifth to top dress with), one pound of Humate, two pounds of Microlife, one pound of Eco-Min and one pound of Sulfur-Miniprill.
Calculate the square footage of bed area you intend to plant to determine the quantity of organic matter and bed amendments you will need as well as the quantity of plants. Most winter annuals don't spread like many summer annuals, so plan on spacing them closer. On average, plant four-inch pots on nine-inch centers to have your beds bursting with color. Divide the square footage of planting bed by .56 to establish the number of plants you need.
Once you reach the nursery, plan your purchase. Most pansies, violas and alyssums stay about the same height, but annuals such as snapdragons and delphiniums can vary greatly in height. Snapdragons from the Solstice and Sonnet Series reach 14 to 18 inches, while the Rocket Series can reach 36 inches. Connecticut Yankee Delphiniums stay around 18 to 24 inches, but Magic Fountain and Pacific Giants will exceed the 36-inch mark.
Try something new. While the pansies with the face, i.e. Majestic Giants, are a long-time favorite, some of the new varieties are offered in solid colors. In a mixed border, using a solid color of any particular plant will result in a better color definition in the overall planting. The Atlas Series of pansies offer a large solid colored flower in individual colors of blue, purple, rose, white, and yellow.
Flowers of various shades of a single color, such as Lilac Shades, Lavender Shades, Pink Shades or Peach Shades, work well too, as long as there are not a lot of mixed colors in other annuals you use (such as a mix of snapdragon colors). When selecting colors for an annual display, I like staying on one side of the color wheel (warm: red, orange, and yellow or cool: green, blue, or purple) for most of my choices and picking one or two plants from the opposite side for contrast.
Shade can be a problem for the winter color garden. Most winter annuals prefer lots of sun. If you get dappled sun the following annuals might work for you: universal light blue pansy, ornamental cabbage or kale, cyclamen and primula.
You should stake the taller growing annuals so they can stand up to the spring storms that blow through. Winter annuals should take a light freeze without covering. Cyclamen are the least hardy of winter annuals. Plant them in the ground in their containers. If the temperature drops below 25 degrees, pull them up and take them inside for protection.
Be sure to finish by top dressing the planting with the compost you saved from bed preparation. A two-inch layer of mulch will act as overnight insulation and mitigate potential cold damage to shallow rooted annuals. Start a compost pile with grass clippings and the leaves that are soon to fall and you will have your own source of compost by next spring. You will want to apply it then to hold in moisture during the summer's heat.
Urban Harvest produces this column. Learn about gardening classes, community and school gardens, farmers’ markets and more at www.urbanharvest.org. The article was written by Suzy Fischer, who is a registered landscape architect and principal of Fischer Schalles, a landscape design/build firm.