Every autumn I marvel at the heads on the hydrangeas growing underneath the giant trees that cover Battlestone Hill at RHS Wisley. They are not the blue or pink-flowered lacecaps and mopcaps (H. macrophylla) that perform in summer, often in seaside locations. These hydrangeas (all named forms of H. paniculata) peak in late-summer and autumn, producing large pointed heads rather like overweight buddlejas. These buxom beauties shine in shade and also make excellent plants for a north wall.

The largest flowers of all on Battlestone Hill belong to ‘Silver Dollar’, an AGM winner. As the ivory-white flowers fade they acquire shades of red and pink. Another AGM star on Battlestone Hill is ‘Vanilla Fraise’, a recent French variety that turns strawberry pink. Again the flowers are large and heavy, and this is a warmly tinted one rather like vanilla ice cream flecked with strawberry sauce. I would love to grow a full range of these elegant yet heavy-headed shrubby plants. However, the only one I find room for in my own garden is ‘Limelight’ AGM. This lights up the shade close to a whitebeam which was already in the garden when I came. Its cool-white heads turn a lime-green — hence the name — and it’s a superb plant. It has smaller heads than many others.

My ‘Limelight’ gets harsh (and incorrect) treatment because it’s at the edge of my snowdrop bed. So it gets cut back in winter so that my star snowdrops can be seen without the shrubby framework. And yet it has come through hard winters consistently.

In reality these glorious hydrangeas should be cut back to their framework in spring. Prior to that they provide winter seed heads. I am not in favour of feeding these with too much nitrogen. The woodier the stems the better they support the heads. Use a potash-rich tomato feed if you must.

In the wild, Hydrangea paniculata grows in mixed forest in Asian regions that include south-eastern China, Japan and parts of Russia. Although the soil is acid on Battlestone Hill, paniculatas are tolerant of all soils. Like many Asian plants, it has an American cousin with quite similar looks — H. quercifolia — the oak-leaved hydrangea. This has similar heads and large jagged leaves that colour up to red in autumn. In the wild it grows in the south-eastern states of Georgia, Florida and Alabama. ‘Snowflake’ AGM is probably the finest.

The one traditional hydrangea mophead I would find room for is Hydrangea macrophylla ‘Merveille Sanguine’. This unique variety has deep-red flowers that age to maroon in winter. The foliage also darkens before the leaves drop. Most of these ‘Merveille’ types were bred by Dumas in the 1930s in France so it’s probably an old variety.

The tough perennial, Persicaria amplexicaulis, produces tapering flowers that last into autumn. There is a pale-pink form, ‘Roseum’, and more strident dark-pinks and reds. Alan Bloom’s ‘Taurus’ is probably the most vibrant. The scale of these plants (up to 2m wide) fits in well with the low mounds formed by hydrangeas. All I need is a larger garden!