With immense flower heads, hydrangeas flaunt a timeless charm that is hard to resist. Hydrangeas are unrivaled in the shrub world for their beautiful flowers. Colors beguile with clear blue, vibrant pink, frosty white, lavender, and rose blossoms—sometimes all blooming on the same plant! Flowers of big-leaf hydrangeas can change color based on the soil pH. Blues are best grown in acidic soils while pinks and purples grow best in alkaline.