Fall is my favourite time of the year. As the temperatures begin to cool down and the days become shorter, plants prepare themselves for dormancy.  There is also more moisture in the ground during this season, providing us with ideal conditions for many gardening tasks.

Cutting back perennials

If you want to reduce your gardening tasks in the spring, much of the work can be done in the fall:

As the temperatures drop and daylight decreases, it signals the plants to go into dormancy.  This is when you see leaves shrivel up and drop.  The plants aren’t dead, just conserving energy to survive the cold winter months.

When to cut back your perennials

In the fall, plants will begin entering dormancy when the day lengths decrease and the temperatures drop.  These factors send a signal to the plant to send all the energy into the root system, which in turn will help it survive the winter months. Ideally, wait until the plant has started to die back on its own before cutting it back.

NOTE: if the plant is diseased, cut it back and dispose of the waste.  Do not place it in your compost bin as it will not heat up enough to kill off the pathogens.

Not all plants enter dormancy at the same so it’s possible to stagger the garden cleanup throughout the fall months.

What perennials to cut back

If the perennial has a woody stem, such as Lavender, Russian sage or Butterfly Bush, treat it like a shrub and do not cut it back completely to the ground. but trim it back to 6-8”.

Avoid cutting Echinacea to the ground in the fall.  This will help with winter survival and also provide a source of food for the birds.

Do not cut back borderline hardy perennials all the way to the ground (Zone 5).  This will allow the plant to trap more snow for winter protection.  It will also be a reminder where they are located next spring, as they are late to emerge from the ground.

If the stem is fleshy, it can be cut down to the ground.

Leave as many plants as possible to provide winter interest.  Ornamental Grasses, Sedums, Allium, Echinacea, Rudbeckia provide a fantastic display throughout the winter months.

What to do with the waste

If the plant is not diseased, the yard waste material can be composted. If the plant is diseased, the material can be brought to the city dump and get processed there, or disposed of.

Plant division

Fall is a great time to transplant and/or divide plants.  The plants are entering dormancy and will be less stressed as all the energy will be going into root production, not leaf and flower production.

I usually avoid moving or dividing borderline hardy (Zone 5) plants in the fall.  Instead, I add protection to the root zone with mulch or chopped leaves.  Transplanting or dividing these plants can happen early spring.

Dry plants are stressed plants.  Transplanting is a stress to a plant as well.  This is why it’s important to water the plant you wish to transplant well and allow it to absorb as much moisture as possible before digging it up.   Also make sure the new area is well watered.  After transplanting, continue watering the plants to maintain consistent moisture in the surrounding soil.  Be careful not to create a waterlogged environment as this can lead to root rot.

Always amend the soil with compost anytime you transplant – plants need food for best performance, and you will be improving the soil structure at the same time.

In the Spring, borderline hardy perennials are much slower to emerge than the hardier species.  Perennial Hibiscus and Miscanthus, for instance, do not show any signs of life until at least the beginning of June.

Feed your gardens

Fall is a great time to top-dress your gardens with organic matter.  You can add 1-2" of compost to the top layer of the soil and let the worms do the work of blending it in.  This will create a soil with better structure, better air circulation, water percolation, and nutrient availability.

Watering and wrapping your evergreens for winter

Evergreens continue transpiring (losing moisture through their needles) throughout the winter months.  Once the ground is frozen, it will be impossible for the evergreen to take up more moisture from the ground to replenish lost moisture from its needles.  This process causes winter burn. 

Make sure to water your evergreens well until the ground freezes.  Irrigation systems sometimes get turned off earlier than required by evergreens.  Do not let them dry out before the ground freezes.

If it’s a newly planted evergreen or one that has suffered from winter burn in the past, create an open box using stakes and white polar fleece.

Click HERE to watch a video on wrapping your evergreen with Winter protection.

Preparing your deciduous trees for winter

Fast growing deciduous trees as well as borderline hardy trees should have their trunks wrapped with either burlap or a white plastic coil in order to prevent sunscald.  The process of sunscald occurs when the sap starts flowing on a warm winter day, and the temperatures drop drastically overnight, causing the cells to burst.  Sunscald is predominantly found on the south-west side of tree trunks.

Plant protection from critters

Spray plants with Plantskydd or Bobbex to protect your plants from rodent damage.  This can be done once in late fall, then again if the residue is washed off later in winter.

Bulbs

Plan your future Spring garden by adding flowering bulbs such as tulips, daffodils, muscari, crocus, and fritillaria.  Place them around plants that are late to emerge in the Spring.  The foliage of the emerging perennials will hide the dying foliage of the bulbs.  Hostas, Hydrangeas, Hibiscus and Echinacea are prime locations to add early spring blooms.

·        A great way to deter squirrels from eating your tulips and other tasty bulbs is to apply Acti-Sol All-purpose Hen manure.  Sprinkle some in the hole as well as at the surface and not only have you stopped the squirrels from digging up your bulbs, you've also added fertilizer to the surrounding area.

Fall is also the best time to plant garlic for a bountiful harvest next Summer. Topdress the area with compost before planting, blend it in then plant the individual cloves.  Add a 6-8" layer of straw to protect the bulbs over the winter and help prevent weeds next season.

Dreaming Season Begins

Once you have completed your fall garden cleanup, make a note of areas that you feel lack winter interest.  Remember that a garden’s beauty should be year-round and not only limited to when the plants are growing.  There is nothing more beautiful than evergreens, shrubs with interesting stems, and perennials that stand up to snow throughout the winter months.

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