Fall is prime time to plant perennials, bulbs, trees and shrubs

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Every fall my mom would grab her gardening tools and wheelbarrow and head out into her perennial garden, casting a discerning eye over what areas were bare and could use a jolt of colour, or pinpointing plants that needed to be separated and moved so they could grow to their full potential.

She knew – as most avid gardeners do – that fall is a great time to plant bulbs, perennials, shrubs and new trees. As the summer heat melts away we’re left with lovely cool days, chilly nights and less humidity – ideal conditions for plants (and gardeners, too).

If spring is an exciting time to get outside and plant, especially after our long, cold winters, fall is the perfect time to make additions, remove underperformers or diseased plants, and lay the foundation for a healthy, vibrant garden in six months’ time.

“Autumn is the time when I look at my garden and figure out what sections need a little bit of help,” says Carson Arthur, an outdoor design and lifestyle expert who owns Carson’s Garden and Market in Prince Edward County, Ont. “Plants put in the ground in the fall have a head start on spring-planted ones – and it’s an advantage they carry through the whole growing season because they’ve had time to establish healthy roots.”

As an added bonus, fall is often bargain time at garden centres that are trying to sell the last of their inventory before winter. “It’s the ideal time to shop for spring-blooming bulbs, perennials, trees and shrubs, all of which can be planted now until your area gets hit with a hard frost,” says Arthur.

Sean James, a master gardener in Milton, Ont., says fall planting is all about nurturing your garden so it can put its best face forward as soon as the snow melts. Popular spring-blooming bulbs that will provide vibrant colour post winter include crocuses, iris, hyacinths, tulips (he adores parrot tulips and the wide variety of variegated species now available), and daffodils (tete-a-tete miniature daffodils, which have up to three blooms a stem, are a perky foil to the larger ones). If you are partial to native plants, now is also the ideal time to plant trilliums, not ones taken from the wild but grown from tissue culture, as well as Dutchman’s breeches, whose flowers look like pantaloons hanging upside down.

Once you have your bulbs in hand, James recommends planting them as soon as possible. The longer they’re out of the ground, the higher the chances are they will dry out. He buys bulbs as soon as he finds them in case they sell out. Eye-catchers such as the showy tulips (fringe and parrot) and rare varieties of bulbus iris (such as Katharine Hodgkin) go quickly, he says. “The earlier you have them in ground, the sooner they come up in the spring.”

James uses a layering technique to plant bulbs, with the heaviest bulbs on the bottom and the lighter ones on top. For instance, he will plant daffodils and tulips at about 25 centimetres deep, and then crocuses at approximately 10 centimetres deep. It’s a nifty trick that also ensures that the early bloomers are closest to the surface.

Arthur adheres to a different philosophy when it comes to bulb planting. He recommends waiting to plant your bulbs until the first frost. “Think of a bulb like a battery. It has a certain amount of energy in it. If you plant too soon, the growth that occurs, takes that energy away from the bulb and it has less oomph for next year. Fall gardening is about practising patience to ensure you get the most out of your plants,” says Arthur, who wrote the best-selling book Garden Designs for Outdoor Living.

His rule of thumb for bulb planting: If a bulb is two inches tall, plant it double the height of the bulb – so four inches deep. To keep squirrels from digging up your bulbs, he recommends putting a light coating of leaves to cover the soil disturbance, then bone meal on top. Squirrels detest the scent.

While visiting the garden centre, take stock of what plants are in bloom, such as fall-flowering hydrangea and grasses, Arthur recommends. “A good rule of thumb is if it is blooming in the garden centre now, odds are it will bloom at exactly the same time next year in your garden. Hydrangea and grasses are a beautiful way to add texture, colour and movement to your garden as fall progresses.”

A wonderful plant for bird lovers is Viburnum, a popular flowering landscape shrub that can be planted now. It produces berries that come in a variety of colours including neon pink, lemon yellow, robin egg blue and deep purple-black, all of which attract birds into your garden during winter.

Fall is also the best time to divide and separate plants that have become overgrown and need more space. “Most plants don’t like to be moved but they do like to be divided – so hostas, black-eyed Susans, rhubarb, echinacea and peonies can all be transplanted this time of year,” Arthur says. He warns, however, that peonies can be finicky. “If anything is going to sulk it’s a peony.” (Note: They should be planted at the same depth as before. If you plant them higher or lower, then they take longer to bloom or produce flowers.)

James, whose company Sean James Consulting and Design specializes in sustainable landscaping, advises that the absolute best gift we can give our garden this time of year is mulch. “Don’t bag up and dispose of your leaves, mulch them with your mower, and put them right back on the gardens,” he says. “They help keep all the micronutrients in the soil and ensures their release to the plants, which makes them healthier and more disease resistant.” A good organic compost or manure can be substituted for mulched leaves.

He also tries to push people away from fertilizing in the fall. “Your plants are going to sleep and need their rest. The last thing we want to do is wake them up.”