Blackberries

My friend Bussie and her husband gave me a twig of backberry last july 4, 2015 when we visited them at ponderosa, silang, cavite. The mother plant of their blackberry is in Guam. I planted two blackberries from the twig and this january 2016, I saw some flowers. By february 14, 2016, I ate some fruits already. They tasted sour. I hope I can make them sweet.