Leaves are turning colour, with beautiful crimsons and glowing yellows taking form along the river valley. Seeds are swirling in the breezy warm air, lining the gutters, and landing in our eavestroughs. It is beautiful fall, and we have been fortunate to have some great weather so far. There is no doubt about it though, the days are getting shorter, the nights cooler, and the outdoor ‘to do’ list, prior to… I won’t say it, seems to be adding up.
Our trees, shrubs and perennials may need a little extra care as the season winds down, and so do our lawns. Here are some tips you may find useful for your yard.
Pruning
As woody plants begin to wind down and slowly enter dormancy, due to the shorter periods of light and downward temperatures, it’s a good idea to hold off on significant pruning of live wood. This is particularly important for trees. The leaves are still doing their job, converting sunlight into useful sugars the tree will store in their roots.
As we move later into the fall, we don’t want to interrupt the transfer of sugars held in the leaves moving down for storage in the root system. Go ahead and remove dead wood and the odd nuisance branch but limit live wood pruning if possible. Elm pruning is still banned in Alberta until October 1, to reduce the risk of Dutch Elm Disease entering these trees.
Planting and transplanting
Fall is a great time to plant trees and shrubs, or move perennials that bloom in spring. There are exceptions, but this tends to be a good time of year for those practices, due to the cooler temperatures. Moving a plant is a stressful process for it, and the high heat of summer does not help matters. It is important to remember though, that plants should have adequate time to root in the new locations.
Woody plants often have a second flush of root growth in the fall, and so if planted in early September, for example, there should be adequate time for trees to overcome planting shock and begin to establish. It is key to water them regularly and fertilize them with a transplant specific fertilizer, which will be relatively high in phosphorus to aid in root establishment.
The same goes for over seeding and sodding lawns. Fall is excellent for both. Schedule your watering accordingly, and there should be adequate time for the seed to germinate, and for new lawns to root in well before the cold of winter.
Fertilizing
Fertilizer programs at this time of year should be less focused on top growth, or vegetative growth, and more tailored to ensure the roots of plants are getting what they need, and the plant is able to endure the colder temperatures to come. Stimulating the wrong type of growth can put plants at risk, as they expend energy developing above ground tissue rather than preparing for dormancy. The key nutrients in a fall fertilizer tend to be phosphorus and potassium, as both play a vital role in root health and plant hardiness, respectively.
Maintenance
There are a few perspectives on what to do with fallen leaves in the yard. Certainly, they can provide a type of mulch for planted beds, and beneficial insects such as lady bird beetles (lady bugs), utilize this litter to over winter in. On the other hand, harmful fungal spores can reside in this material and can enter plants in the spring. Leaves left all winter can contribute to snow molds and other turf issues. It really depends on the application. A good rule of thumb is to clean up leaves around woody shrubs and trees and rake them up or mulch them into the lawn.
Weeding
What makes trees and shrubs vulnerable this time of year holds the same for perennial weeds. Weed pulling or treating the foliage of a weed prior to it going dormant can be very effective. With less sunlight and cooler temperatures plants struggle to recuperate as well from these methods.
Watering
With all the tasks to complete outside ahead of the cold, remember to have your irrigation system blown out too. If you are a new homeowner this can be easy to overlook. In the meantime, lawns require less water as they wind down growing for the season, and so this is a good time to adjust to a fall watering schedule. The warm weather we have been experiencing means that trees and shrubs should still be getting effective, deep watering with longer intervals in between.
Evergreens are susceptible to evaporation all winter, particularly during chinooks, and so watering them well prior to colder temperatures may provide a reserve of moisture in the soil they can utilize through dryer times.
We hope you enjoy all that this colorful season has to offer. Happy gardening, from Parks and Recreation.
Jeff Quinlan is the parks technician for the City of Medicine Hat, which involves technical support for the department through research, insect and disease monitoring (of trees), and public education/engagement through things like the Adopt a Tree program and the annual Litter Blitz. Quinlan is an ISA certified arborist with a Bachelor of Applied Science in Horticulture. Prior to being in Medicine Hat, Quinlan also worked as a Japanese Garden Technician for several years at Nikka Yuko, Japanese Gardens in Lethbridge. His gardening tips will appear in the News throughout the growing season.
