As I write this we have had weeks of hot and dry weather with temperatures breaking all previous records. It has been the single hottest period in the 32 years that I have been here at Knoll. While at this moment it feels like it may never rain again it undoubtedly will do so – and with such enthusiasm that we will be complaining about too much water! This cool and wet and then hot and dry regime seems to be the new normal; at least for the time being. From a gardens perspective the trick of course is to use plants that can best cope with the prevailing conditions – and in this there is absolutely nothing new.
A combination of our Naturalistic approach and the Right Plant Right Plant ethos leads us to use plants that are best suited for the particular conditions – and it is perhaps in extreme periods like this that we see the massive benefit of such an approach.
While we will irrigate when necessary and when we can the garden is a little under 4 acres and water is supplied though a number of taps to which hosepipes and sprinklers are manually attached. This manual system involves a reasonable amount of extra work for us and so we are not keen to water unless really necessary. In practice this means that only about half of the garden is ever periodically irrigated. The rest has to cope.
Panicum are warm season grasses, as are pennisetum and miscanthus, and they have really seemed to enjoy this summers heat and drought. Chosen for its blue foliage and ability to reliably perform in our UK climate, Panicum Sea Mist offer superb mounds of blue – grey to sea green foliage, and flowers, whose colour only seems to intensify as conditions get drier. Drought adapted and beautiful!
Our Gravel Garden is sited in one of the hottest and driest parts of the garden. The combination of a thin sandy soil and the gravel surface makes for a very well drained and dry environment that a number of plants find to their liking. Statuesque grasses such as the magnificent Stipa gigantea and Panicum Sea Mist are used to provide accent and outline with perennials such as Gaura (oenothera) Whirling Butterflies, Scabiosa ochroleuca, aster and agapanthus being used to provide an annual bonanza of effervescent colour, delicacy and lightness.
Although the gaura and scabious have a reputation for being short lived (3 to 5 years), they are so well suited to the conditions that they will seed and so we never have to replant. As the plants, in this respect, have more or less taken over the design each year the display is a little different – but never fails to impress. After a cool start this spring the plants were a little slow to get going but are now seemingly revelling in the summers heat and showing their approval with masses of flower.
As well as these blowsy perennials there are a number of self seeders, often annual or biennial, that are encouraged to grow wherever they feel best. The towering spikes of yellow belong to a mullein that has never been intentionally planted but which seems to position itself so effectively each season. Daucus carota, the wild carrot, has also never been deliberately planted but has arrived of its own accord – and is most welcome to stay. Elsewhere in the garden the evening primrose self seeds and is, season by season, now gradually moving into the Gravel Garden where its bright yellow rounded flowers seem to work so beautifully with the dainty soft whites and yellows of the gaura and scabious.
The soft blue mounds of another drought tolerant grass, Poa labillardierei, gives background structure to part of the Gravel garden as does the rather taller, and impressive, Arundo Macrophllya.
In the Decennium border the distinctive upright habit and trademark beige of Calamagrostis Karl Foerster is looking pretty fabulous and with only a minimal amount of watering even in this severely dry period. This is a particularly useful grass as it will also cope with quite heavy and winter damp soils. A grass for all seasons??
Planted relatively recently a circular bed of Hakonechloa Aureola surrounds a newly planted sorbus tree, which was found as a seedling within the garden. Hakonechloas are another very useful grass for quite dry soil positions, in sun or shade, and while they can be a little slow to get established are subsequently very long lived.
Sesleria Summer Skies is a superb compact grass that seems to revel in hot and dry conditions when its foliage colour seems only to intensify. We have it growing well in the garden but it also has done very nicely in a large container as part of our pot display by the garden entrance.
There are not that many flowering perennials that are happy in shady dry places – but the white wood aster, Aster divaricatus (new name Eurybia divaricata), is a most welcome exception that seems to survive in dry and drought prone shady areas. Very pretty and very tough.
An ever so pretty native grass, Melica uniflora albida, is so drought adapted that it will grow in the driest of conditions and often goes to sleep for the summer once its spring display has finished. Bright mounds of fresh green foliage is topped with airy dainty looking white rice grain like flowers during spring to early summer.
