Hydrangeas are to summer what Azaleas are to spring: a dramatic punch of color in the landscape. In older neighborhoods, large shrubs of mophead Hydrangeas dominate the garden with billowing blue flowers signaling the start of summer. Blue is a rare color for flowers and will get plenty of attention; stealing the show from other flowers. But not all Hydrangeas are blue. White, pink and purple mopheads can also be found along with Lacecaps, Oakleaf, Peegees and Arborescens. Lacecaps and mopheads are closely related. Botancally they are Hydrangea macrophylla and native to Japan. The color of the flower depends on the pH of the soil. Most of the Hydrangeas around here are blue because the soil is slightly acid. Adding lime in the fall will turn the flowers pink the following summer. If you want to have fun with your hydrangeas, sprinkle a hand full of Lime on one side of the bush and a hand full of Aluminum Sulfate on the other side. When the Hydrangea blooms you will have pink, purple and blue flowers. This trick will not work with white mop heads but they will blush with pink hues as the flowers fade. Hydrangeas age gracefully turning mauve, slate and chartreuse and other antique shades providing weeks of changing colors.
If you are trying to grow more native plants then Oakleaf and Arborescens Hydrangeas are for you. Both were traditionally white but now a few pinks are on the market. Pinky Winky Oakleaf starts out white and turns pink as the flower ages. Oakleafs need really good drainage, plenty of sun and room to grow. They often get 12 feet tall. The orange fall leaf color is a bonus.
The cultivated Arborescens Hydrangeas have huge white mopheads and often need staking. The wild forms look more like Lacecaps with smaller flowers. ‘Annabell’ is one of the most popular cultivars but new pink cultivars have hit the market in recent years. Plant them in morning sun or dappled shade.
Pruning Hydrangeas can be a little tricky, but the old garden rule “Prune after the bloom” holds true for Hydrangea macrophylla both mopheads and lacecaps. Flower buds for next year form in the summer. Flower buds are easy to identify –big and fat compared to leaf buds. So when you prune, cut just above a fat bud. But all hydrangeas can go for years without pruning. I only prune them when I cut them for flower arrangements. Peegee and Arborescen Hydrangeas bloom on new wood and can be pruned in the winter without loss of bloom. Peegees and Oakleafs can be trained up like a small tree.
When purchasing Hydrangeas look for repeat bloomers and new color combinations to try in your garden.