If its syrup, and it's in a sealed bottle or pouch, don't even boil it. Pour it straight into the fermenter. Don't need to stir either. The yeast will find the sugar and work its way through it, whether it's evenly dissolved or a puddle at the bottom. When going for high gravity Belgians, it's actually good practice to hold back on the syrups until this point, to get the yeast going and achieve high krausen.
Rdwhahb indeed...