Fall Planting

Dianne and Gary Westlake


We usually forget that fall is a great time to change, move or add to your perennial beds. If you plant now, there is plenty of growing time left for the plants to settle in and get ready for winter. You can continue to plant up to six weeks before the last expected hard freeze. A touch of frost won't hurt the roots and there will also be fewer insect and disease problems. We have successfully planted well into November in some years. Plants that have outgrown their space can be divided and used to fill in bare spots or shared with a friend.

We tend to be very excited about working in our gardens in the spring doing most of our planting and a huge number of other garden tasks. Leaving all of this work until spring often results in the overtaxing of both the body and mind. Gardening should enjoyable not a marathon.

In fact, for some perennials, fall is the best time to transplant. Peonies for example spend the summer with small feeder roots feeding the storage root. If you disturb the plant too early, you will set it back by damaging these small roots. Once fall comes around, feeder roots die back to the storage part and it is safer to move them then. If you wish to add a peony or two to your garden this is the time. We are blessed with a peony grower, Blossom Hill Delphiniums and Peonies, nearby where great variety of peonies are available.

In the fall the soil is warm which will encourage the roots to grow, whereas in the spring the soil is still cool and will have to warm up before growth of the roots can begin. Air temperatures are cooler causing less stress on the plants and on the gardener.

Rainfall tends to be more reliable and the soil will be moist in the fall. This year it will be a welcomed relief if the rains ever come!

Fall is a great time to plant trees and shrubs. In the past, the soil that was excavated was amended with manure or compost prior to back filling the hole but the latest research suggest that roots tend to stay in the amended soil and do not venture into the harder native soil. So it is better not to do much amending of the soil in the planting hole, which ultimately results in a larger more vigorous root system.

Dig a good-sized hole that is two or three times as wide as the root ball and approximately the same depth. Simply break up the soil and remove rocks. In most cases it is best to gently remove some of the potting soil and tease out some of the roots to get them started. Add a dusting of bonemeal in the hole to encourage root growth and use the native soil to refill the hole. Do not use any other fertilizer that will stimulate top growth.

Because newly disturbed soil has a tendency to settle, position the plant at or slightly above the surrounding soil level. This will help to avoid the potential development of root rot or disease. Better to plant a tree or shrub slightly higher and allow the area to drain than to allow it to sit in a depression and collect excess water. This is particularly important in clay soils.

Tamp the soil gently around the roots to ensure good contact. No stomping with all your weight! Water well to provide moisture and to get rid of air pockets that can contribute to root damage. If support is needed for your new tree, make sure that it is not tied too tight or it will constrict growth of the trunk. Also make sure that it is removed as soon as it is no longer needed so that the tree can grow strong on its own.

Mulch heavily with organic matter such as compost, shredded leaves or straw to retain moisture and keep soil temperatures moderate. Form a saucer shape the size of the planting hole but do not allow the mulch to come in contact with the bark. Add a protective barrier around the trunk for the first winter to protect it from rodents. If the weather is dry, water regularly until the ground freezes. Using a large pail with a tiny hole on one side an inch above the bottom is a good strategy. On alternate days, fill the pail and allow the water to drip onto the root area.

The other good thing about fall planting is the availability of great deals on plants at the garden centres. The nurseries do not want to have to hold the plants through the winter so they often offer them at discount prices to clear the stock. Of course you should be careful to choose healthy plants. A sick plant at any price is no bargain!

The Peterborough Horticultural Society is holding a Fall Plant Sale for the first time in a number of years. Here you will find locally grown plants at great prices. The sale will be held of Saturday, September 15 from 9:30 to 11:30 in the parking lot of St. Alban's Anglican Church located at 567 Monaghan Road. Master Gardeners will also be available to answer any questions you might have so come out and pick up some gems from our gardens.

Now is a great time to do some of your planting. It spreads out some of those physical tasks.