Solaris: Problems with Hardiness
Updated: May 24, 2021
Starting with an article reporting poor results is maybe not the best way to begin a blog, but it can only get better from here. Solaris has had a prominent place in northern grape growing partly by being a variety 'authorised' for growing by the EU and being available in large enough quatities for planting of commercial vineyards. Here nothing is grown in large quantities, and the focus has always been the lesser-known varieties. Nonethless in 2009, two Solaris were obtained and an attempt was made to crop the variety under outdoor conditions.
The results were not good, but I have never seen any data for the variety under northern conditions so I will report the numbers to give an indication of how close to ripening it got. The first and only berries produced were two small bunches which were used as a test in 2010. That year budburst was very late for all varieties here, for Solaris it was 17-18th May. The first flower opened on 13th July and flowering continued until 29th July. During this time the weather was dominated by high pressure over the Azores causing a progression of low pressure systems to move in from the west around the top of the high, i.e. wet. Fruit set was poor but a few small berries were produced. These achieved an average sugar content of 7.1 degrees Brix on 25th September, and 10.7 degrees Brix on 6th October after which ripening ceased. Inferring how ripening may have gone had the season started earlier from only two data points is fraught with uncertainty, but it could be construed that had there been two weeks extra ripening time or the season started two weeks earlier, it may have reached an acceptable sugar content for winemaking, perhaps around 17 Brix. Put another way, if it had started growing in the first week of May, it may have been harvestable by the first week of October. That is not fast enough for this site, so while the variety may be fast relative to varieties such as Chardonnay grown in the south ofthe UK, it is not fast relative to other varieties grown here.
There was not another chance to test the ripening speed. In the following years the Solaris vines were setback by frosts in April, and despite at first managing to regrow from secondary buds, the season was not long enough for proper maturation of the wood, and the vines were ultimately lost. The years 2010-2012 were cold and the vines would likely have been more successful had they been tested in 2014 or 2018, but it was decided not to continue with the variety because there were many others to chose from.