I covered my hydrangeas with shrub covers in November, as instructed I piled dried leaves over the plants before securing the cover. The covers do provide light and moisture. I am now wondering when is a good time to remove the covers and next steps following that. The shrubs did have buds when I covered them. I am in Lindsay, so the weather is a little cooler than in Toronto.
Hi – Sounds like you are taking good care of your hydrangeas. Hydrangeas are susceptible to our cold winters. A late-spring frost can do particular harm so I would not rush to remove the protection. Keep your shrub covers in place until the late spring when the buds start to swell. According to the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), the average last frost free date for Lindsay is May 17. As this is an average and will very somewhat from season to season, I would suggest you start checking for bud swell around May 10 or earlier if we are having a mild spring.
Once you’ve uncovered your hydrangea, have a look for any damaged stems and prune these out. Hydrangeas thrive in a moisture retentive soil with good organic content so adding some compost around the base of the plant followed by a layer of mulch to retain moisture will help. Note that the time to prune hydrangeas varies by species, so spring may not be the best time to prune for shape or to regenerate the plant. I’ve included a link below to an article on the best time to prune the different hydrangea species. Enjoy your garden.