Hydrangeas are beaut!
HYDRANGEAS are a classic garden plant, often conjuring up images of old-fashioned cottage gardens rather than contemporary ones.
But in the past few years hydrangeas have been enjoying a well-deserved resurgence in popularity, as we appreciate just how easy to grow, long-lived and beautiful they really are.
With their lovely neat mounds of lush green leaves, topped by clusters of little buds that grow plumper by the day, they are a highlight formed in semi-shaded situations from mid spring through to the end of summer.
In full bloom, the large, striking heads of flowers in shades of blue, purple, pink, cerise and white are just gorgeous.
The foliage too is lovely, with large, dark-green oval leaves, often with serrated edges.
I always think that the lushness of the foliage and the (mostly) cool tones of the flowers have a cooling effect in a summer garden.
There are more than 70 species in the hydrangea genus, including small trees and climbing varieties.
But what we commonly call hydrangea is usually hydrangea macrophylla of which there are more than 600 cultivars of this species alone.
Hydrangea macrophylla originated in Asia and Japan and was brought to Europe in the late eighteenth century where it quickly became highly prized.
Hydrangeas are the flower of Mothers' Day in France, just as the chrysanthemum is here in Australia. They are widely grown for cut flowers.
In the cultivated hydrangeas there are two main flower types.
The most common form is probably the Moptop, which produces large heads of simple, flat four-petalled flowers.
Lacecaps have these flat flowers around the outside of the head, surrounding a centre made up of masses of tiny, intricate, lacy flowers.
Hydrangeas are an easy-to-grow, fast-growing deciduous shrub to 1-3m.
Flower colour is somewhat variable according to soil conditions.
Acidic soils, such as ours here in the Byron Bay area, will generally produce blue flowers, whereas alkaline soils will produce pinker flowers.
White varieties will tend to remain white, although they may be tinged with blue or pink depending on the soil.
The newer named varieties are pretty true to colour, given a neutral soil ph.
You can influence the flower colour if you want, adding lime to push the flower colour towards the pink end of the spectrum or hydrangea blueing tonic to go the other way. Be careful though, because the pH level of your soil affects the plant's ability to take up nutrients, so you don't want to fiddle too much!
Ideally, plant hydrangeas in a partly shaded position, protected from strong winds and hot sun.
Not too shady, though, or you will have beautiful leaves and few flowers. You'll need moist, well-drained soil, of course, enriched with plenty of organic matter.
They look spectacular in pots. Use water crystals when you plant and keep the plants well mulched as they don't like to dry out.
Avoid watering the foliage in the evening in summer, as this can encourage fungal disease.
The same is true, incidentally, for roses, geraniums, even zucchinis and cucumbers, and other plants prone to fungal conditions.
Prune after flowering, around March or April, and remove any old or dead wood.
Don't prune too hard, though, and leave stems that haven't flowered as they may do so next year.
Some of the new compact forms don't need much pruning at all. You can pick the flowers for the vase and they can even be dried.
Look out for the evergreen hydrangea, dichroa versicolor, which produces lovely blue flower heads.
It's not really a hydrangea but it definitely looks and behaves like one, although it retains its foliage year-round. It's more sun-hardy than its deciduous cousins.