I want to replace 5 low-growing junipers which have been killed by the last 2 harsh winters. We live in south Etobicoke (zone 5?) and the area is full sun and has good soil which I try to amend with compost yearly. I also have some other low-growing evergreens in the same area. I want to keep their height to no more than 2-3 feet high at maturity. Any suggestions for a hardy variety.
You are definitely not alone in the loss of your evergreens. In spite of their promising moniker, there are certain severe conditions, including winter burn on leaves and branches, that have wrecked irreparable damage to our conifers.
Members of the Cypress family, Cupressacae, Junipers grow both as trees and shrubs. This family is cone-bearing and has opposite or whorled needle-like leaves. Your species is perhaps Juniperus communis, Ground Juniper, which mature to about 1.50 m. tall. You mention other low-lying evergreens, which may include Juniperus horizontalis, that has a creeping growth habit to about 30 cm. in height. They both love full sun, can handle light shade and will tolerate average soil.
Your original choice of Junipers was a good one for south central Ontario zone 5b which, in a year long period can experience temperatures up to a 60°C differential from hot to cold. Further, Junipers lend themselves so well to a variety of uses in gardens, from specimens, to prickly barriers, to groundcovers, that I would suggest you try some different low-lying species. You may wish to look at J. scopulorum (Rocky Mountain Juniper), which can be trained into a spreading habit, or J.squamata which is a single seed juniper. It might be useful for you to look at actual specimens in situ to help visualize your options, so perhaps visit a variety of nurseries.
Once you have chosen, planted and mulched your new plants, remember to generously water right up to ground freeze-up in late autumn.
Attached below are a links to related TMG articles which you may find helpful.