Hello hydrangeas

One of the intriguing characteristics of mophead hydrangeas is how the flower bracts change colour. This is related to aluminium levels in the soil. The flowers are generally blue in acidic soils where aluminium is freely available, with pink dominant in more alkaline soils. Curiously, white bracts stay white but can become slightly tinted as they age. New breeding has produced mophead hydrangeas with variegated blooms and leaves, double blooms, lacecap blooms, and more.

Hydrangeas make stunning pot plants when they are in flower but it’s best to move them to a less prominent position during their leafless winter period. In the garden, these deciduous shrubs flourish in dampish soil with some protection from the hot summer sun.

Varieties such as pee gee or panicle hydrangea (H. paniculata ‘Grandiflora’), which flower later in summer, are also popular. Panicle hydrangeas are larger than mopheads and very cold tolerant. H. paniculata cultivars such as ‘Sundae Fraise’ have long-lasting flowers that change colour throughout the season. The leaves of oakleaf hydrangea (H. quercifolia) turn rich red shades in autumn.

Reader’s question: I would be grateful if you could tell me how to help my cut hydrangeas last longer in the vase. Pam Ward, Geelong, Vic

Judy Horton says: Hydrangeas can be frustratingly short-lived in a vase but there are some tricks that will help them to last longer. Firstly, wait until the flowers have been fully open on the bush for at least a couple of weeks. Pick them early in the morning or in the cool of the evening and put them straight into a bucket of water. When you are ready to arrange the blooms, remove the lower leaves and recut the base of the stem on a 45-degree angle. Immediately dip the cut base in boiling water and leave for a few minutes to break down the sap that can block water intake. Some growers will smash the bottom of the stem to achieve the same result. The water in the vase should be as high as possible without any leaves being submerged. As the blooms in the garden age, the petals become papery and develop lovely antique colours. Picked at this mature stage, the flower can be dried by removing the leaves and hanging the bloom upside down in an airy spot out of the weather. If the flowers dry completely, they can last for years.

Read our article Heavenly hydrangeas for more stunning varieties!

Header image credit: iStock