Place flowers into a canning jar and cover with boiling water. Cover and place in a dark place for 24 hours. Next day, strain and save the liquid. Peel crab apples and cook for 10 minutes in a little water. Strain and collect the juice. Combine the two liquids and bring to a boil for 1 full minute. Add sugar, mix thoroughly and boil for another full minute. Skim surface and pour into hot sterile jelly jars and seal.