Hydrangea serrata 'Blue Deckle'Hydrangea serrata 'Blue Deckle' Mountain Hydrangea Blue Deckle is a compact shrub, rarely growing taller than 1. 25 m. The lacecap type flower heads have a frilly appearance due to serrated sepals. The colour can vary depending on soil pH, from pastel blue in acidic soils to pale pink in alkaline ones. More neutral pH can also yield pale lavender flowers. In addition to flowering on terminals, this cultivar can also bloom on side shoots, meaning that