Do you mean 3 separate shades ie. sangria, lilac and silver?
Lilac and sliver definitely go together but I'm not sure about sangria - it really depends on the shade of each color but assuming sangria is a strong red color (the color of sangria wine) then it may be too much of a contrast with the other two colors.
Remember also that a color will look different on fabric versus flowers.
I suggest you get hold of fabric color swatches and take them to a florist so you can put things alongside one another. A visual solution to deciding on wedding color matching is usually the best one!