2 days ago
The secret to growing your best hydrangeas ever
It's hard to think of a plant that sums up late summer and autumn quite like the hydrangea. You only have to walk down any road or glance into a front garden at this time of year to see them in their full summer glory, dripping with big blooms in every shade from soft pink to vivid blue. They're as much a part of our landscape as old stone walls and grassy lanes, bringing a gentle sense of familiarity that feels like home.
Whenever I ask my garden design clients about any particular plants that they may like or dislike, I am normally met with quite a vague response, such as 'I really like most plants' or 'there's not really any that I do or don't like'. But say the word hydrangeas and people's reaction is immediate. They will either say 'I love hydrangeas' or 'No, I don't want any in my garden'. Why such strong feelings, I have no idea, perhaps it's because they remind us of the past, for they are a really traditional plant in many Irish gardens.
Our mild, damp climate suits them perfectly, which is why they've become such a fixture of gardens here. The classic type most people know is Hydrangea macrophylla, with its lush mopheads. Mopheads give you those big, rounded balls of flower, while lacecaps are a bit more delicate, with tiny true flowers in the centre surrounded by a ring of showier bracts. Both thrive in part shade and moist soil, flowering from midsummer well into autumn.
Then there are the paniculata types, with long, cone-shaped heads of white flowers that often turn to pink as they age. They cope with more sun than mopheads and are ideal if your garden is a bit more exposed. Varieties like Limelight and Vanille Fraise are particularly worth keeping an eye out for. The hydrangea du jour right now is Hydrangea Annabelle, grown for its enormous white heads that seem to glow and change shade as the sun moves through the day.
One question that always comes up is how to keep hydrangeas blue. It all comes down to soil. In acidic ground, aluminium is more available to the plant, which gives you those striking blue flowers. In neutral or alkaline soils, the same plant will flower pink. If your soil is naturally on the limey side, you can try feeding with aluminium sulphate or growing in pots of ericaceous compost. Just remember that it's far easier to keep them blue in containers than to change an entire border's pH.
Looking after hydrangeas is fairly straightforward. Watering is crucial, especially in dry spells, as their big leaves and heavy blooms lose a lot of moisture. A good mulch in spring will help keep roots cool and damp.
When flowers fade, you can deadhead by cutting just below the old heads, though I would suggest leaving them on through winter for a bit of winter interest and to protect next year's buds from cold snaps. Come early spring, trim back to a pair of strong buds. With paniculata and arborescens types, you can be a bit braver and cut them back harder in late winter, as they flower on new wood.
There's something special about old hydrangeas in walled gardens or running along the sides of old houses. They seem to carry stories with them, year after year, tying us to the gardeners who came before. They maintain interest through late summer and give that connection between summer, giving that reliable backbone when many early summer flowers are starting to fade and the more muted space of winter.
Hydrangeas also work well with other plants. They look lovely with hostas and ferns in shadier spots, or underplanted with hardy geraniums for a softer, more natural feel.
If you're planting a new hydrangea, take the time to prepare the ground well with plenty of organic matter. The more work you do before planting to improve the soil, the greater the dividends in the longer term, as a really humus-rich soil, which will conserve moisture, will mean less watering in the dry periods. Plant it at the same depth it was in the pot, keep it well watered in its first season, and it will reward you for years.
So now, while they're at their absolute best, is the perfect moment to enjoy hydrangeas in all their glory. Whether it's a deep blue mophead glowing in a shady corner, a frothy paniculata turning pink as the days shorten, or a pure white Annabelle, standing proud by the garden gate, they bring a quintessential charm that few other plants can match. They anchor a garden, linking us to the past while promising colour and beauty for many summers to come.
