Photo's 1) Joffre cluster with most of the berries gone after testing brix
2) St. Croix cluster
Some details on grape varieties growing in Edmonton. These include St. Croix, Marechal Joffre, Edelweise, and Acadie Blanc.
These varieties are disease resistant and cold hardy. The Joffre and Acadie Blanc are cold hardy to about -30c and the St. Croix and Edelweise cold hardy to about -33 to -35 c.
We had about 18 inches of snow on the ground this past winter and had cold of -35c. As a result the Joffre and Acadie died back to the last buds an inch above the soil. The Edelweise and St. Croix budded out between 6 and 12 inches above the soil. The Acadie and Edelweise had no flowers bu the Joffre had one small cluster which flowered about July 4th and the St. Croix has about 7 clusters which flowered about June 27th.
The summer came late about 2 weeks or so and it has been a cool dry year in Edmonton. The degree days are at about 625 - 650 year to date. Historically Edmonton gets about 135 frost free days and 750 degree days of heat, so in theory there is enough frost free days for very early varieties but the winter cold usually kills the canes and buds off. But 750 degree days is very low on the heat.
Veraison on the Joffre cluster started about August 20th and September 5th for the St. Croix. Tested the brix today and the Joffre is about 19 brix (about 70 days from flowering) and the St. Croix is at about 7 brix.
Going to lay the canes right down on the ground this winter to see if that changes the cane and bud survival rate. Hopefully we'll get some clusters on the Acadie and Edelweise next year as well. If you could get the Joffre to survive the winter in Edmonton you'd have a nice grape for this area. Will see how well the St. Croix does before the frost comes.