Garden Detective: finishing fall chores

Sara Norkelun, 22, plant sneezeweed, a perennial that

Sara Norkelun, 22, plant sneezeweed, a perennial that grows to about 4 feet. (Sept. 1, 2012) (Credit: Randee Daddona)

Jessica Damiano

Jessica Damiano, Newsday columnist Jessica Damiano

Jessica Damiano is a master gardener and journalist with more

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Annuals are fading, late-summer perennials are on autopilot and leaves soon will be changing colors. The garden is going to sleep, so there's nothing left to do but kick back with some cool cider and enjoy the view, right?

Not so fast.

There's a lot of work to be done now to keep plants and soil healthy and ensure that, come spring, you won't be buried in cleanup work or under a pile of crowded, overgrown perennials. Stay on top of your autumn chores and you might even get to enjoy that drink come April.

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I'll start by letting you off the hook with a couple of don'ts: You don't have to fertilize and you don't have to prune, so scratch those off your list. Pruning is for February and March, with an exception for spring-bloomers -- wait to cut them until just after the show has ended. And fertilizing anything now (including grass) will stimulate growth that won't have time to harden up before frost, leading to winter injury and a loss of energy that shouldn't be spent on growth right now.

What's more, much of that expensive fertilizer won't get absorbed by plants anyway, and instead will leach into groundwater, where it will pollute the water table.

Here's what does need to be done, broken up into three manageable groupings of just five chores each. Tackle one at a time and you'll really enjoy the beauty of your autumn garden.

CLEAR AND MAINTAIN

Weeds: Pulling up weeds -- by their roots -- is always important, and autumn is no exception. Neglecting weeds will grant them a free pass to strengthen their presence both in quality (some will even turn into unwanted trees) and quantity (blowing seeds and running roots can lead to a population explosion next spring).

Leaves: As leaves begin to fall, rake them up from the lawn, pavement and beds. The best way to avoid spending an entire autumn weekend doing yard work is to keep on top of leaves. If you clean up every few days, you might even enjoy the chore, as it will allow you to pull on a soft sweatshirt and enjoy some fresh air without feeling overwhelmed or straining your muscles raking for hours.

Perennials: Most plants can be cut nearly to the ground, to about 3 inches, in autumn after they've died back. Doing so earlier would deprive them of precious time needed to store up energy for next year. When plants do die back, you'll need to decide whether to cut them away now or before new growth begins in spring. With few exceptions, this is simply a matter of personal preference, although there are benefits to allowing them to stand until spring, as they provide above-ground insulation that helps protect roots during harsh weather.

Some plants, like Echinacea (purple coneflower), have seed heads that can feed birds over the winter, when other food sources are scarce. Those heads also catch the falling snow, adding an ornamental element even in the dead of winter. Others, like butterfly bush, bishop's hat, fern, lavender, Lenten rose, chrysanthemum and ornamental grasses should always be left in place until spring. In fact, cutting a butterfly bush nearly to the ground, which should be done each year, could prove fatal to the plant if undertaken in autumn.

Still, there are plants that should be cut back in fall. Any that have been affected by mildew or disease over the past season should be removed and the surrounding area cleared of debris, with all plant matter discarded in the trash. Low-lying plants with large leaves, like hosta, should be cleared away, too, before frost turns leaves yellow and mushy, making cleanup more difficult. Those leaves also would provide shelter and a nice breeding ground for unwanted insects and rodents over the winter.

Annuals: All summer annuals should be removed and discarded. Consider replacing them with pansies, which will lend color until frost and bloom again in spring. Pansies are annuals, too, but their life cycle runs from fall through spring, not spring through fall. It's the summer heat that kills them off; unlike other annuals, they survive winter very nicely.

Crops: Harvest the remainder of fruits and vegetables, and clean up any that have fallen. Avoid leaving any on the ground, where they'll rot and attract rodents. Some, like tomatoes, will even plant themselves and root where you don't expect them. Cut down spent plants, pulling up roots when possible, and compost if plants have been healthy. Diseased plant matter should be thrown out. Incorporate compost or well-rotted manure into vegetable beds now, tilling it in 4 to 6 inches deep so the soil will be ready for planting come spring.

PREPARE AND PROTECT

Soil: Have your soil's pH level tested, and amend it if indicated by the results. It takes three to six months for lime to work into the soil deeply enough to benefit roots. Treating soil now will ensure soil levels are corrected by planting time.

Mulch: Two to three inches of shredded bark mulch will go a long way toward protecting roots from heaving out of the soil (or too close to the surface) during the freeze-thaw cycles of winter. But wait until first frost before mulching or you'll risk trapping warmth in the soil, which may delay the roots' dormancy and make them susceptible to winter injury, stressing and possibly killing the plant.

Water: Although trees and shrubs appear to have stopped growing, continue to water until the ground freezes. Roots are still growing underground and are busy storing up food and energy for next year. Broadleaf evergreens, like rhododendrons, will become susceptible to winter burn without sufficient water during fall, as roots will pull the water they need from leaves faster than it can be replaced, resulting in scorched foliage.

Relocate: As a rule, fall-blooming plants should be moved in spring, and spring-blooming plants should be moved now. Dig up and relocate spring bloomers, taking care to replant at the same depth, as different plants require different planting depths. Add organic matter like compost to planting holes for a nutritious boost, firmly tamp down soil to eliminate air pockets around roots, and water well. Identify summer and fall bloomers you'd like to move before they resume growth in spring, and tie a ribbon around each so you'll recognize them while they're still dormant.

Tender bulbs: After the first light frost turns foliage brown, cut plants such as Canna, Colocasia (elephant ears) and caladium down to 6 inches and dig up rhizomes, corms or tubers. Rinse, separate bulblets and allow to air dry completely, then place in peat moss in a box with holes cut for ventilation. If you're dealing with a large quantity, a milk crate works well for storage. Keep in a cool, dark place, such as a crawl space or cellar, where they won't freeze, and check monthly, spritzing with water if you notice shriveling.

PLANT AND DIVIDE

Perennials, trees, shrubs: This is a great time to get steep discounts on perennials, as nurseries are having sales to clear out their inventory, but proceed with caution: Snap plants up as long as they look healthy, and use them to fill in gaps you noticed this year, but avoid the temptation to buy one of everything. Sticking with just a few different varieties in odd numbers will keep the garden from turning into a jumble.

Most trees can be planted in fall, too, except for red maple, hickory, crape myrtle, dogwood, tulip poplar, magnolia, callery pear, oak and silver linden; for best results, hold off until spring for those. At the nursery, look for potted trees whenever you can; those that are balled-and-burlapped (B&B) were dug up from the ground and may have suffered root damage in the process. Dig a hole twice as wide as the root ball and exactly as deep, and mix one-third compost to two-thirds of the soil removed from the hole. Backfill, tamp tightly and water well. Shrubs should get the same treatment.

Bulbs: Start planting bulbs, corms and tubers beginning late this month and continuing until the ground freezes. There really isn't a deadline: As long as the ground is soft enough for you to dig a hole, a bulb can be planted. Choose a spot with good drainage and plenty of sunlight, taking into consideration that shady summer spots may be sunny in spring before trees leaf out.

As a general rule, bulbs should be planted pointy end up, 2 1/2 times deeper than their diameter, so a bulb with a 1-inch diameter, for example, should be planted 2 1/2 inches deep. From a design standpoint, avoid planting in straight rows, opting instead for drifts. It's easiest to plant entire beds all at once because you can dig up the whole area, lay the bulbs in place, and cover it all up fairly quickly. Adding bulbs to existing beds will require one-by-one planting using a dibble, spade or auger.

Edibles: Plant separated, unpeeled organic garlic cloves 2 inches deep in full sun. Position them with their pointed ends facing up, and space 3 to 6 inches apart in rows 12 inches apart. They will remain dormant during winter and send up leaves in early spring, with garlic bulbs ready for harvest in July. Avoid planting conventional garlic purchased at the grocery store because many have been treated to prevent sprouting.

Sow seeds of spinach directly into the ground. They'll start growing in early spring, before your neighbors even plant theirs.

Lawn: Late summer is the ideal time to seed or sod the lawn. The soil is still warm enough for roots to thrive, but getting cooler so tender new growth won't be as susceptible to heat stress as it would have been earlier in the summer. And because weed growth has slowed, there won't be competition for water and nutrients.

When selecting grass seed, look for disease-resistant, drought-tolerant varieties. For light shade conditions a 100 percent fine fescue blend sown at a rate of 4 to 5 pounds per 1,000 square feet is best; for a low-maintenance lawn in a sunny area, consider a 100 percent tall fescue blend sown at a rate of 7 to 10 pounds per 1,000 square feet.

Lightly rototill the soil and incorporate compost before seeding and then immediately give the area a good, deep soaking. After the initial watering, provide a light sprinkle once or twice a day to keep the soil from drying out until grass fills in.

To fill in bare patches, simply seed spots once a week and water lightly every day until new growth fills in. Hold off on mowing until new growth is 3 to 4 inches high.

Never fertilize newly planted grass, but apply an organic slow-release nitrogen fertilizer to existing turf as soon as possible this month. Core aerate the lawn to break up compaction and allow oxygen to reach down to roots.

Divide: If spring- or summer-blooming perennials were crowded or showed signs of decline this year, now is the time to divide them. Most perennials -- coneflowers, black-eyed Susans, daylilies, Dutch irises, catmints, hostas and the like -- can be divided very easily by inserting a spade or long-handled garden fork in sections all around the plant, leaning on and rocking the tool's handle with each segmentation to loosen the rootball. Lift the plant out and, using a flat-edged spade, cut the root system into two or more pieces, depending upon the size of the plant. (For smaller plants, simply tear sections apart with your hand.) Take care to ensure there are at least two or three leaves above each root division, and plant each in its own hole. Continue watering until frost, but don't fertilize.