Adding plantings to your landscaping is always an exciting part of your landscaping plan. But, knowing when to add plants to your landscaping in spring is very important. Calgary is famous for unpredictable spring weather. The spring weather can be warm and balmy or freezing and with below zero temperatures. Below zero temperatures can spell disaster for new plantings so be cautious when installing new plants.
The famous May long weekend rule still applies
If you listen to the news and climate change stories you may think the city climate has warmed to the point where we can safely change our planting habits. Believe it or not, there has been very little change in our spring weather over the past several decades. Calgary is still unpredictable and year round temperatures overall has changed very little if at all. This means that the famous long weekend rule still applies. The rule is to only install new shrubs, perennials and annuals after the May long weekend. Large trees may benefit from this rule as well but large caliper trees can be planted before the May long weekend. There is a great risk in planting shrubs, perennials and annuals before May long weekend and that risk is hard frosts. Frost is considered a hard frost when temperatures are below -5 celsius. When temperatures drop this low they can do serious damage to your plantings. Fresh buds on your plantings will freeze to the point where they will not recover. This can stunt or set back the growth of your plantings or even kill the plant altogether. Planting trees and shrubs can be done early but you may need to take cover.
If you do choose to plant early then cover your garden beds!
If you decide when to add plantings to your landscaping in spring by just checking the short term forecast you may be disappointed. It is no secret that the fresh new buds on spring plantings are very vulnerable to hard frosts and cold temperatures. Much more vulnerable in fact that full grown established leaves. If you do choose to install your plantings early then watch the forecast and make sure to cover vulnerable plantings if you see a hard frost coming. You can cover your shrubs, perennials and annuals in many ways including using burlap, blankets, potato sacks, tarps, poly material or landscaping fabric. If you do cover your plantings make sure to have the covering extend right to the soil. This will trap the heat from the soil and help protect your plantings even more. You don’t have to restrict your planting covers to new plantings. If you have some favourite established shrubs and perennials in your front or back yard you can cover them as well. Covering these treasure plantings will give them a head start in spring. If the established plantings do not have new buds or growth then you do not need to worry about covering them.