There have been some unwanted effects of the persistent wet weather we have experienced this summer.
Lawns which traditionally start to go into hibernation by this time of the year have been growing at almost mid-spring pace. And as for weeds! It almost feels like they spring out of the ground the second you have finished weeding and then outgrow the plants they are infecting.
Fortunately, there is an upside to all this growth – some desirable plants love it. Unfortunately, that does not include the petunias I planted for the first time in ages. They are unhappy with the lack of sun and seem to have the flower factory down.
The impatiens in the hanging baskets love the humid air and grow magnificently.
This is also an excellent year for hydrangeas – everywhere I walk to see masses of these old-fashioned favourites having a great year, obviously enjoying the moister weather.
Although these shrubby plants went out of fashion for a while, the swing towards massed plantings has seen them recover some of their popularity, as they can usually be relied upon to give a generous showing of flowers over the summer.
I have noticed some of the smaller growing varieties used for basal plantings around buildings, especially those with paler colours.
The most popular types of hydrangeas, at least in New Zealand, are the mop-headed forms of the common hydrangea, the ones with great balls of flowers. Technically speaking, the attraction of these shrubs is actually the lack of flowers – the true flowers have been replaced by modified leaves, called bracts, in the same process as poinsettias and some viburnums.
These flowerheads have an amazing journey. They start out green in the spring, and then as summer approaches, they slowly colour, keeping their brightest colours through summer.
When autumn arrives, many of them undergo another transformation, taking on the strangest metallic tones.
As well as mop heads, there are lace caps – lovely varieties where there is a mix of true flowers and bracts. I think the prettiest of all are those where the bracts form a ring around the outside the perimeter of the flowerhead, with the true flowers in the inside. One of the most startling of these is the recently introduced ‘Strawberry and Cream’, with red bracts surrounding cream flowers.
Both these classes of hydrangea have the ability to change their colours according to the pH of the soil they are growing in. In simple terms, the more acidic your soil, the lower the pH, the bluer the flowers will be. Conversely, the higher the pH, the pinker the flowers should be.
In reality, it is not quite as simple as that, as some cultivars are naturally stronger coloured that others, and your ‘pink’ hydrangea may end up a deep raspberry colour and others will have navy blue rather than Cambridge blue.
Even the “white” varieties can subtly change colour depending on the soil chemistry, having light pink or mauve undertones.
There are several other hydrangea species that are worthy of garden space. In the Unites States, they love “peegee” hydrangeas, a slightly ugly contraction from the species name of ‘Paniculata Grandiflora’.
Those with a working knowledge of botanical Latin will know that this means the flowers, which are large, are carried in panicles.
This is a slightly different beast to the garden hydrangea. It grows about twice the height of a standard garden hydrangeas, and only comes in white, or very lightly toned flowers. These flowers, which are carried in large cone-shaped panicles, are composed of bracts, and appear quite late in the season. In the past few years some light pink and even chartreuse-green varieties have become available, both very attractive.
The oak-leaved hydrangea, H. quericifiolia, has flowers like the “peegee”, but it is much smaller growing. The oak shaped leaves have a copper cast, and the flower heads are conmical inshape, and usually a mix of bracts and true flowers.
I have grown the ethereal H. aspersa villosa, a shrub with a rather open habit. In summer it carries soft racemes of delicate lace cap flowers, the blue bracts shimmering in a slightest breeze. It is a lovely plant for light shade, or even full sun.
If all these hydrangeas are driving you up the wall – there is at least one species that will join you – H. petiolaris. This is a hardy deciduous climbing, self-clinging, that will happily scramble up a fence or wall, making woody growth as it goes.
Come summer, it will have masses of white flowers, in a similar fashion to a lace cap, sitting over the top of deep green foliage. It makes a wonderful change from the more usual climbers.