Throughout the summer, we have had numerous customers coming into the Garden Centre, asking for advice on Hydrangea care. The most common issue we have observed is little to no flowering, best time to prune and watering. This blog will hopefully provide some useful details on how to ensure your Hydrangea blooms year after year.
Hydrangeas are much-loved deciduous hardy shrubs, some of which are climbers. Their striking flower heads come in a range of shapes, from large balls to cones. The most popular and recognizable types are Mophead and Lacecap, of the Macrophylla family, with large, rounded flower heads in shades of white, blue and pink in summer and autumn. However, differing Hydrangeas such as Paniculata and Aborescens are also common.
Pruning - Macrophylla (Lacecap and Mophead):
Prune in mid-spring. They produce their flowers on old wood, so don’t prune them back hard, or the summer’s flowers would be lost. Traditionally, the old flowers are left on over winter as it protects the new growth beneath. Cut back the flower head to just above the top set of plump buds that are forming under the dead flower head. This is where the new flowers will form. If you have an overgrown plant, cut some of the stems off at the base.
Pruning - Paniculata and Aborescens:
Cut back in early spring. Pruning is not essential, but left unpruned the plant will get taller with most of the flowers at the top. These two types of hydrangea produce flowers on new wood, which means that you can cut them back harder without losing the year’s flowers. Prune last year’s growth back to a healthy framework that’s between 30cm and 60cm high, depending on how tall you want your plant to be. Prune to just above a pair of healthy buds on each stem.
Applying a slow-release fertilizer once a year is going to be your simplest solution to feeding your hydrangeas. There are plenty of slow-release fertilizers on the market. You can use any fertilizer formulated for shrubs and trees. However, we would recommend to use Westland Chicken Manure Pellets in early Spring. This will provide your hydrangeas with continued nutritional release throughout the season for healthy growth.
How do I change the color of bigleaf hydrangea flowers?
Most flowers will change color naturally from white to pink and then lavender over time. In some varieties, such as 'Endless Summer', the flower color is influenced by the pH of the soil. The flowers turn blue when bigleaf hydrangea grows in acidic soil (pH<6), while the flowers are pink to red when it grows in alkaline soil (pH >7). The flowers are purple or blue-pink in slightly acidic or neutral soil (pH 6-7). Aluminum sulfate can be used to make the soil acidic, while lime may be used to make the soil alkaline.