Ailsa and I both like hydrangeas.
These flowering shrubs, which range in height from about 1 metre to 3 metres tall, although the genus also includes small trees and even includes several lianas, are, essentially, parasitic plants which climb up other trees, rather in the manner that sweet peas climb up their supports.
Those climbing species of hydrangea can attain a height of 30 metres … say, 100 feet in old money … and, I hasten to say, our garden lacks any of those, just as it doesn’t boast any 100 foot tall trees. But we do have a selection of Hydrangea macrophylla and one splendid Hydrangea paniculata, all in full bloom right now in mid-September. And this fact … they bloom in late summer and early autumn … is both one of their most attractive features and yet one of their least attractive. If, gentle reader, you can afford the space in your garden for a shrub which just sits there for much of the year, dully meditating in its usually rather dark green foliage before bursting into wonderful bloom, then hydrangeas may be right for you: but if space is at a premium, you may well wish to allocate this scarce resource to plants which provide interesting colours in foliage and flowers for rather longer.
We are fortunate to be in the former category and, as I have said, have a selection of hydrangeas spread throughout the garden. We also have soil which varies from being rather acidic to being slightly alkaline, probably as a consequence of the house-builder’s introduction of top soil many years ago, and now I’m going to get very technical for a moment. Soil is said to be acidic if it has a pH of lower than 7, where pH is, to quote the Oxford English Dictionary, “a figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid and higher values more alkaline. The pH is equal to −log10 c, where c is the hydrogen ion concentration in moles per litre.” And no, I don’t understand the second sentence in that definition either! But I do know that in some cultivars of the very widely-grown Hydrangea macrophylla … the ‘plant with cup-shaped fruits (Hydrangea) which has large leaves’ (macrophylla) … the flower colour will be influenced by the relative acidity of the soil: a soil pH of less than 7 will encourage the plants to produce blue to purple flowers, whereas soil with a higher pH level is likely to result in pink or red flowers.
Our currently very splendid Hydrangea paniculata … the hydrangea ‘with flowers in panicles’ (paniculata), panicles being loose branching clusters of blooms … languished in one area of our garden for several years, looking proper poorly pretty much all year round. We didn’t understand what ailed it but, since we dug it up and transferred it to a different part of the garden, it has been transformed! Gone is the hang-dog plant of yesteryear, replaced by a lively, thriving shrub with a beautiful show of white flowers which are now gradually becoming pink, a sight to delight any gardener’s heart on a parky September day. And the reason? Well, at first we thought that it had been planted in part of our garden with alkaline soil, while it wanted to grow in acidic soil: but I now know that the alkalinity or acidity of the soil is of little account to the health of most hydrangeas, which will prosper in either; and I think now that it simply did not get enough sunshine. It was a straightforward matter of location, location, location. The shrub is rewarding us for satisfying one of its basic needs with huge blooms which would delight any recipient of an arrangement in which they were featured; and, in the romantic words of the celebrated Asian florist Tan Jun Yong, quoted on Wikipedia, “The light delicate blush of the petals reminds me of a beating heart, while the size could only match the heart of the sender!”