Looking around the lanes and gardens in August you can’t fail to notice the number of Hydrangeas that are in flower. Here in Cornwall where the temperatures are mild all year round and where there is plenty of moisture they grow into enormous shrubs in colours ranging from the purest white to the darkest purple.
The one place to visit to see these flowers en masse is Trebah Garden on the Helford River. This is when they take centre stage. The plants here are hand pruned in early spring which helps promote the abundance of flowers that remain until long into the autumn. The majority of these were planted in 1949.
Included in the species are H. aspera which has soft velvety leaves. Bees collecting pollen from this plant accumulate a blue sac on each leg rather than the usual yellow.
H. quercifolia has large oak-like leaves which develop burnished tinges in autumn.
H. paniculata “Vanille Fraise” (Strawberry Vanilla) has large panicles of white flowers that turn pink as the summer progresses. This one I have in my own garden.
Hydrangea Valley is filled with plants of all shapes and colours. The pretty ‘Monet’ style bridge provides the perfect place to see them with reflections in the Mallard Pond.
If you want to see more of this lovely garden then please click on this link to my other blog: Cornwall in Colours
One of the most dramatic flowers at this time of the year is the golden Rudbeckia fulgida ‘Goldsturm’. Also known as ‘Black-eyed Susan’ with large, golden-yellow, daisy-like flowers up to 12cm (5in) across with cone-shaped, blackish-brown centres from August to October.
This knee-high plant bridges the gap between summer and autumn providing welcome colour to the garden. Best planted in drifts among other late flowering perennials, Rudbeckia works well in prairie-style schemes with ornamental grasses. They like a sunny spot and to be kept moist especially when in flower.
Bees, butterflies and other pollinators love it too.
White-tailed bumblebee. August 2019. Click image to enlarge.
In late summer it is the turn of the hotter colours to take pride of place in the garden. The pinks and purples of earlier months are now starting to look tired and dusty. Orange, yellow and red herald the turning point in the garden, a last hurrah! Crocosmia x crocosmiiflora is a garden hybrid of C. aurea and C. pottsii, first bred in 1880 in France by Victor Lemoine. This hybrid between two species of this lovely South African genus, a cross aimed at producing a select plant with adequate hardiness, is known to gardeners as “Montbretia.”
The sword-like leaves and brilliant wands of fiery scarlet, red, orange, and yellow flowers add dramatic structure to the garden and look particularly good grown alongside grasses and other tall flowers like Kniphofia and Rudbeckia or Helenium.
Crocosmia “Lucifer” (below) has sprays of vivid red flowers on stems to 1.2m in height. Others are lower growing, but may need support as they can flop around.
Crocosmia “Emily McKenzie” is a particularly delightful plant with arching spikes of yellowish-orange-red freesia like flowers.
Those left to their own devices tend to dwindle into congested, grassy clumps, but if you dig up a clump you will see that the corms build up on top of each other. Twist off the topmost corm which is the one taking in the energy from this year’s foliage and replant these in a shallow trench a few inches apart and a few inches deep. In spring add achilleas and grasses to mix with them and create a naturalistic planting style. Dispose of the old corms carefully. Normal compost heaps will not be hot enough to break them down so you might find a garden full of them in the future!
Here in Cornwall, during the months of August and September, the vigorous Montbretia can be found growing wild in clumps in the Cornish hedges. Escapees find themselves in my garden!
Annuals come into their own this month and none more colourful than the Cosmos which was introduced into this country in 1800 from Mexico. These big, bright and beautiful daisy-like flowers come in many colours and heights. The most common variety C. bipinnatus with large yellow-eyed daisy flowers in the burgundy-red-pink-white colour range include the taller ‘Purity’ that will grow to 1.2m and suited to the back of the border. The shorter varieties like ‘Apollo’ are good to grow in containers and new types include ‘Xanthos’ the first yellow-flowered variety. Keep the containers fairly large though as even the shortest plants reach 45cm tall and as much across.
Varieties derived from C. sulphureus have smaller flowers in scarlet, orange and yellow shades set against slightly broader, darker leaves. [unfortunately I do not have any images of this type]
C. atrosanguineus is the Chocolate cosmos which is hugely popular with richly chocolate-coloured, and chocolate-scented, flowers. This is a half-hardy perennial that develops tubers like those of a slimline dahlia and may need to be overwintered indoors. This is also a good candidate for containers.
Cosmos enjoy plenty of sunshine and any reasonable soil, although rich, moist conditions encourage exuberantly leafy growth at the expense of flowers. If you ensure to deadhead throughout summer into early autumn, you’ll continue to get beautiful flowers right through the season.