That could be a hint. Stone fruits are the hardest kinds to manage in the home orchard. Are nectarines even winter hardy where you are?
Check the findings of others in the area before concluding these have been shown to be hardy there. Unless yours have been there many years or through the coldest winter in a long time, you may be in for a setback. Here in the States the USDA Cooperative Extension Service network tests orchard fruits and provides information about suitable varieties and locations. Don't know what is available there.
Hi John; You could try some of the earlier cultivars developed at Harrow, Ontario. If you try the research station at Kentville they might be able to help you out. What peach variety are you growing there now. http://www.omafra.gov.on.ca/english/crops/facts/07-041.htm This website might help you out . Cheers