This time of year, flower gardens start looking tired and ready for bed. Before snow blankets their neighborhoods, gardeners have some tucking in to do.
Jill Johnson of St. Paul, Minn., must decide the appropriate moment before the ground freezes to sacrifice a 4-foot by 6-foot bed of annuals. She needs the space to bury her climbing rose, which she has successfully overwintered for seven years. Typically, she says, she waits for the first light frost, then takes her spade out the next week.
Other gardeners have less-typical autumn tasks: David Edlund of St. Paul will rent an air compressor to blow water out of his drip-irrigation tubing.
But everyone has to rake leaves and tidy up their gardens and almost everyone has to mulch.
The trick to mulching is to wait for a killing frost, says Tom Huiras, who owns a Roseville, Minn., greenhouse. Afterward, dead annuals pull out completely; perennials he cuts to about 6 inches tall, because the stems hold mulch against winter winds.
He does not spread hay and straw over perennial beds until the ground freezes hard. “You’re covering to keep the stuff from thawing out,” Huiras says. “In winter, most of our perennials will take being frozen, but thawing and refreezing kills them.
“Say you get 10 days of sunny weather in January and we don’t have any snow cover,” he says. “More often than not, the plants will start to try to grow. They start sucking water from the roots, get their cell systems all filled with water. Then, it comes along and gets cold and shatters those cells.”
While waiting for a good hard frost, gardeners can take the opportunity to assess the garden and, if possible, improve it for next year.
Although she likes summerlong blooms, Johnson finds massive spring plantings of annuals onerous. Perennials require planning to stagger flowering, she says, but “you get beautiful bloom times, and your garden is always changing.”
Along with the perennial Russian sage she recently brought home, Johnson will plant tulip bulbs. “I try to outsmart the squirrels who follow behind me and dig them up and eat them,” she says. “I cover the tulip bulbs with chicken wire, weigh that down with bricks and cover it with annual vines until the ground freezes.”
“A garden is three or four gardens throughout the season,” says David Edlund, who cultivates a luxuriant example on a small St. Paul lot. “It’s easy to misjudge a blooming period and you’ll have a hole, or the colors won’t be as you wanted them.”
Early fall planting suits perennials, trees and bulbs. Roy Robison of Landscape Alternatives recommends planting perennials while the soil remains warm. He says: “Wildflowers in particular are gearing down for the season, so they concentrate on root growth.”
Also divide perennials now, Edlund says. “Not only do you increase your supply,” he says, “but you make a lot of friends.”
Some years, he would have started dividing earlier, he says. “I let the fall tell me when to divide,” Edlund says.
Fall and spring are the best time to plant trees, says David Harich Jr., manager of Lilydale Garden Center. “Temperatures might freeze sometime in October,” he says, “but the ground doesn’t really freeze up until well into November. Trees have some time to take hold.”
Aside from a couple of exceptions, such as birch, young trees also should be wrapped. Maples and crabapples, for instance, still new enough to sport smooth skins, should be wrapped from the ground to the first branches.
“Wrapping will protect against freezing and thawing, which causes cracks over the winter,” Harich says, “and it also protects against bunnies.” Once snow covers other forage, rabbits will gnaw thin tree bark, he says; if they eat even a 1/4-inch ring around a tree, they can kill it. (Remember to take off the wrap in the spring.)
Cool-weather vegetables — broccoli, cauliflower, brussels sprouts and lettuce — will be the reward for an August planting, says Lynn Steiner, editor of the Minnesota Horticulturist magazine who nurtures a large vegetable garden in Washington County.
“All four of those vegetables will take a light frost, and the brussels sprouts will be fine down to 28 degrees or so,” she says. “Brussels sprouts actually benefit from a little frost; most people think they taste a little sweeter.”
Steiner hopes to harvest vegetables through October. “I really won’t start putting the garden to bed until mid- to late October,” she says.
Because the cold makes trees go dormant, pruning trees and shrubs also makes sense in the fall. In addition, once leaves have fallen from deciduous trees, gardeners can see their structures much better, says Mike Zins of the Minnesota Landscape Arboretum. A person with an apple tree, for instance, might want to open it up to encourage production.
Take off dead branches, cut limbs hanging too low over sidewalks and prune one of two rubbing branches, he suggests. But before starting, look above, below and all around for power lines, Zins says.
No matter how often the public is reminded, he says, “it’s surprising how many people end up 10 toes up because of power lines.”
MULCHING AND MORE:
– To prevent snow mold, keep mowing the lawn until it stops growing.
– Those who fertilize their lawns should apply one last dose in mid-October.
– Analyze garden for flaws and try to fix them.
– Check out your local garden center; many have fall sales.
– Plant perennials; divide established perennials.
– Plant bulbs for spring flowers; dig up bulbs of such flowers as dahlias to store inside.
– Plant trees; mulch with 6 inches of wood chips; if little rain, water weekly.
– Don’t fertilize established trees; it’s like giving sugar to a child right before bedtime.
– Wrap most young, smooth-barked trees from soil to first branches.
– Prune trees and bushes.
– Use the Minnesota tip method to bury roses that are not winter-hardy.
– Wait till after killing frosts to pull up annuals, cut perennials to 6 inches, weed beds.
– Once the ground freezes, usually in November, cover tender perennials with hay, straw or other mulch.
