Last summer I planted four Hydrangea paniculata ‘Bobo’, a recently introduced, dwarf cultivar. It is not like me to plant four of anything – after all I could have bought four different cultivars and had the chance to compare them. But in this area I just wanted simplicity and a row of the same was what I needed. It was chosen because I can’t grow H. macrophylla well in this garden and this spot, hot and dry in summer, was suitable for this species. It is a narrow bed in front of the summer house and I didn’t want anything too big that would block the view and make passing on the path difficult. ‘Bobo’ was introduced, to much fanfare and, it seems, a lot of publicity in the US, but is quietly gaining popularity in Europe. The compact habit is the main selling point of this one and the flower clusters, mainly of sterile, showy flowers, are relatively run-of-the-mill, opening ivory white from green and ageing to pink.
Mine were planted late last summer. They were hard pruned this March and April. I find that the dead look of these hydrangeas is very worrying in winter. The plants were small in spring and I had to prune them for a photoshoot. These have to be photographed at least two weeks before publication date so one plant (the one nearest the camera) had to be pruned in early March. It took ages for anything to happen and signs of life to appear. I then pruned the other three in late April, just as I saw slight green spots of growth. As it happens, the timing of the pruning has made no difference to the amount of bloom or the timing of flowering. One plant has only just produced flower buds and is well behind but, to confound me, it was not the first to be pruned, nor is it at the end of the row – I can’t explain it.
I underplanted with viola ‘Blue Moonlight’ which is a perennial viola and a very useful thing. I propagated a hundred or so last autumn and they have been planted in lots of places to provide easy, and fragrant, colour. They should cover the ankles of the hydrangeas. But the hydrangeas are so compact that the violas are threatening to swamp them! Worse, the pot of scented plants behind, filled with fragrant pelargoniums, lemon verbena and (unscented) Ageratum corymbosum, is making a tidal wave of growth that may swallow the hydrangeas. I could move the pot or, more practical, cut it back to take the necessary cuttings to maintain the plants. As it happens, having just written this, I went out and moved it! Right, back in.
Hydrangea paniculata is native to Japan and eastern and south China. Like most hydrangeas, and some viburnums, it has mostly fertile flowers, with tiny petals, and a few sterile flowers that do not produce seeds but serve to attract the pollinators to the fertile flowers. Of course, gardeners like showy flowers so forms with more, or all, sterile flowers have been selected – compare sterile mophead hydrangeas with the more delicate lacecaps. Hydrangea paniculata was introduced, to Europe, as the ‘normal’ form, in 1861, but never really caught on. In the wild, this plant is very variable and grows to 9m high on occasion. ‘Grandiflora’ was introduced in 1870, from Japan, and forms a dense pyramid of flowers. It is known as ‘PG’ or ‘PeeGee’ in the US. It is a striking plant with panicles of almost all sterile flowers. The fade to pink and then brown in late autumn.
In recent years lots of new cultivars have been introduced, mostly either with green flowers or those that change to pink early in their life and ‘Vanilla Fraise’ is the most common of these and very striking indeed. ‘Fire Light’ and ‘Zinfin Doll’ are also good for rich pink. ‘Pinky Winky’ from the same breeder as ‘Bobo’ has relatively ‘open’ clusters of flowers, for a ‘lighter’ display but the flowers at the tips remain white as the lower ones turn red, to give a two-tone effect. All benefit from hard pruning in spring to thin the shoots and promote large heads of bloom.
I am sure it is not just me but I think it is natural for paniculata hydrangeas to take a couple of years to get established and really settle down to perform as they should. I have two others elsewhere in the garden, including ‘Vanilla Fraise’ and they were really ineffectual in the first two years; only now, in their third year, are they really doing well, though the current heatwave and drought is taking its toll on them.