Contractors have dug up our front garden (while repairing our leaking basement), including perennials, shrubs, small trees and bulbs, leaving roots and root balls exposed in clumps on our front lawn.
I have meanwhile loosely covered them with plastic bags to prevent the roots drying out. I am concerned they have no protection from the elements and require a soil covering until they can be replanted, which will at best, be in a couple of weeks time. I have been told by the condo landscaping supervisor that the plants are dormant and that there is no need to worry. The Forsythia is in full bud and Irises are shooting, as are other perennials.
Please advise ASAP. We maintain our front garden ourselves.
You are correct to be concerned about your plants.
When plant roots are exposed, one needs to worry about drying, but at this time of year, temperature fluctuations can also cause serious damage. With your roots exposed during the day the roots are warming up, then quickly freezing again overnight. The delicate root structures break down and can be badly damaged or die. Years when we get a good snow covering, helps avoid these large temperature differences as the snow acts as an insulator. Unfortunately for your plants, this year in Toronto there is no snow to offer any protection.
You need to insulate your plant roots to minimize damage from dehydration and temperature fluctuations. Putting soil and mulch over the exposed roots will give them the protection they need until you can attend to them properly in the spring. You should be able to purchase garden soil and mulch now at your local nursery. With this warmer weather you may be able to dig them into the garden beds at least a bit to help with insulation. This is called “Heeling in” a plant. There is a site which gives some information on this process included at the end of this answer. Some of your bulbs could be potted up into containers giving them a temporary home.
When transplanting your plants in the spring you may need to divide the perennials, removing any damaged/dead roots and keeping the healthy plant parts. Amending the garden soil with compost or a well rotted sheep manure will help supply nutrients and give the plants an extra boost when they break dormancy. When transplanting ensure the plants are set in at the same depth they were before the construction – do not bury them deeper than they were. Also, water them well once you have them in their new location. I have included a link to another Master Gardener page which discusses transplanting perennials.