Fall for Landscaping!

Are you starting to think about doing a little more than just the usual gardening? A little more than weeding and deadheading and cleaning? Are you yearning to hold a shovel in your hand? There’s a reason hard work is calling you: it’s almost fall!

The summer season in Canada (July and August) are difficult times for earth moving and planting (a.k.a. “landscaping”) due to the much higher temperatures and general lack of precipitation (2025 in southern Alberta notwithstanding). During this season, opening the soil to air and heat has several complications: soil requires extensive water use to maintain hydration, constant vigilance to ensure that extra water goes where it is needed (during one of the busiest travel seasons known to Canada), and germination rates of many varieties of seeds decline with higher temperatures. Not to mention how difficult it is to physically labour in summer temperatures. I often tell folks that landscaping in July and August is much like landscaping in January and February: It is mostly a waste of time, money, and effort. As far as water use goes, it is extremely wasteful and should be avoided.

The shoulder seasons of spring and fall, however, are the optimal times to get digging, planting, transplanting, and seeding. Here are the basics:

Digging

If you can dig it, you’re landscaping. In some areas and depending on the regional weather, that means starting as early as February and going as late as December. In the fall, as the northern daylight fades and nighttime temperatures decrease, your landscape is in less danger of losing moisture when you start digging and exposing soil. You should avoid digging soil that is very saturated (as it will cause compaction and endless headaches trying to get it off the shovel) but otherwise, dig away! If you can get a shovel under a sod layer, you can remove it. I really recommend opening up areas you want to plant the following spring in September through November, as it gives you a jump on the NEXT shoulder season. Mark out new beds and create them in the fall! 

Planting

I get many questions about planting purchased trees, shrubs, and perennials in the fall. Yes, you can plant in the fall. In fact, late August and early September is the big sale season for garden centers: most of them want to clear their lots and houses before the cold temperatures set in. You can get GREAT deals this time of year. You need to water trees and shrubs 1 gallon of water per foot of height per week until they go dormant (the same as in the spring and summer) but they should come out of the winter just fine. In fact, if you’re not sure where you want to put them, you can tuck them IN THEIR POTS into an annual bed or a hole in your lawn so their root ball is in the ground and insulated against our frequent chinook temperatures. I like to throw a pile of wood mulch over all my root balls (especially those that are in south locations) to further the insulation, but that’s another article. Water-in well. 

Transplanting

Are some of your perennial plants spreading too far? The fall is a great time to separate and plant in a new location (or give away to deserving friends and neighbours). The basic rule for transplanting: DON’T do it if the plant is flowering (it will almost certainly kill the new plant and hurt the existing plant). Use a sharp, clean shovel and slice swiftly through the root ball, lifting out the new plant. Place in a hole that is as deep as the root ball (so the base of the plant is even with the ground) and backfill with existing soil (don’t add nitrogen to fall plantings as you don’t want top growth this time of year), pressing down firmly to set the new plant. You may also move small trees and shrubs that aren’t performing in their current locations. Again, don’t forget to water-in the transplant. Even if plants aren’t growing, the moisture will help to insulate the root ball when the ground freezes.

Seeding

As soon as temperatures are consistently below 5 degrees Celsius at night, I often throw self-sowing annuals as well as flowering perennials (that require cold stratification): cornflowers, poppies, lupins; herbs like creeping thyme and hardy oregano; edibles like spinach and lettuce. The fall is also a fabulous time to overseed weak spots in your lawn with clover or fescue varieties, as you don’t have to worry about keeping the seed moist: simply rake out a spot, sprinkle a bit of native grass seed/clover, toss a bit of dirt over the seed and leave it. Seeding in the fall is the ultimate in low-fuss gardening. 

You have a bit of planning time yet, as Lethbridge temperatures (day and night) are still quite warm. We are nearing our traditional first-frost date which is generally the second week of September, however, so get stretching for some serious fall digging!