The August Garden 2022

As I write this at the height (hopefully!) of the July heat wave my wish for August is for more cloud and rain please- yes, I know I’m not really a summer person! A day later my wish has been granted early and the rain has just started and I can hear thunder in the distance- some might say be careful what you wish for!

Whatever your preferences for weather I hope that you and your garden have managed through the heat and that you are looking forward to August with whatever it may bring.

In the second half of July our garden here in south west Wales is dominated by our lovely Hydrangeas and our three Buddleja bushes and therefore you won’t be surprised to know that these are two of my featured plants for August. In the rear garden we have two Hydrangeas which we inherited with the garden- a dark pink, almost red ‘Mophead’ and a very large light blue and violet ‘Lacecap’.

In the shady front area there are two more which we have planted in the last few years, both blue ‘Lacecaps’. One is a true blue but the other starts white then turns to blue with a white centre in the larger, outer petals and then slowly turns to a dusky pink.

The Buddlejas are full of flower and are beginning to be visited by both bees and butterflies. We do dead head as much as we can to keep them flowering although this can be quite a task as they have so many flowers on them.

Other flower colour comes from a lovely rose, Rosa ‘New Dawn’, which has pale pink flowers and is beginning to climb happily into a nearby Silver Birch (Betula pendula). Below this sits the dark pink Hydrangea and an early flowering pink Japanese Anemone, Anemone ‘September Charm’. In the gravel bed the Betony (Stachys officinalis) is also in full flower and also attracts its fair share of pollinators. It does seed around a little but is very easy to control and transplants to other areas of the garden very successfully. Another pleasing combination at this time is a second Buddleja which was labelled B. ‘Black Knight’ but I think is probably B. ‘Royal Red’ along with the purple-leaved Cotinus coggygria ‘Royal Purple’ and a wine-red Clematis, C. viticella ‘Madam Julia Correvon’.

All these and more featured in the August 2020 blog which is available in the archives as are the jobs for August which for some reason are under July 2019. The August 2021 blog featured our day at the Aberglasney gardens and contains some excellent ‘summer’ plants and is well worth a first or even second look.

Moving on to my plants of the month I will start with the wonderful Buddleja (also spelt Buddleia) which is a genus of around 100 species of evergreen, semi-evergreen and deciduous shrubs from riversides, rocky areas and scrub in Asia, Africa and both North and South America. They are grown for their often large panicles of small, tubular, usually fragrant flowers and their lance-shaped opposite leaves (apart from B. alternifolia). They are also very easy to grow in full sun even in poor soils. Some panicles are conical in shape, others are in rounded clusters along the stem and some have separate rounded clusters. Buddleja davidii, B. alternifolia and B. crispa are very attractive to pollinating insects such as bees and butterflies hence the common name, ‘Butterfly Bush’. The most widely grown are those with conical panicles such as B. davidii of which there are many cultivars including ‘Empire Blue’, ‘Royal Red’,’ Fascinating’ (lilac-pink), ‘Black Knight’ (dark purple-blue), ‘Nanho Blue’ and ‘White Profusion’. This group all flower on the current season’s growth and are cut back hard in spring (March/April) to encourage lots of new growth from the base and to keep the whole plant to a manageable size. Other Buddlejas  such as B. alternifolia and B. globosa flower on last year’s wood and are pruned after flowering by cutting back flowered shoots to new growth lower down and by cutting a few of the oldest stems back to the base to encourage young replacement growth. B. alternifolia with its alternate, lance-shaped, slightly silvery leaves has long pendulous panicles with rounded clusters of small, lilac flowers which are very fragrant. B. globosa is very different with separate, rounded clusters of fragrant, dark orange and yellow flowers on upright panicles in early summer.

The Hydrangea genus is comprised of around 80 species of deciduous and evergreen shrubs and climbers found in woodland in E. Asia and both North and South America. They are grown mainly for their large, showy,  white, pink, red or blue flower heads many of which change in colour into autumn- whites often turning light lime-green, light blues turning to eau-de-nil (Nile green) and others adopting deep russet-red and purple shades. Many also have interesting flaky, peeling bark

when mature and attractive leaves with good autumn colour. They prefer a good soil to which generous amounts of organic matter have been added which helps to keep the roots moist- there is a clue in the name!

The commonly grown Hydrangea, H. macrophylla, can be divided into two groups:- ‘Lacecaps’ have flattened flower heads with small, fertile flowers in the centres, surrounded by large, sterile flowers while ‘Hortensias’ or ‘Mopheads’ have spherical flower heads of large but sterile flowers. Some cultivars of H. serrata are also described as ‘Lacecaps’.

Flower colour is not just down to the cultivar or time of year, it is also affected by the availability of aluminium ions in the soil (not iron as many people think) which is in turn connected to the pH (acidity/alkalinity) of the soil. Acid soils with a pH of 5.5 and less produce blue flowers while soils with a higher pH produce pink flowers. White flowers are not affected by pH. If you don’t have a soil pH of 5.5 or less then the best way to grow a blue Hydrangea is in a container with ericaceous compost watered preferably by rain water, not tap water.

For most Hydrangeas including H. macrophylla, H. serrata and H. ‘Preziosa’ pruning is done in April when last year’s flower heads are trimmed back to the first bud or pair of buds beneath.  Also a third to a quarter of the oldest stems can be cut back to near the base to encourage new replacements.

There is, however, another group of Hydrangeas, H. paniculata, with their conical panicles of typically white or pink flowers. These flower on the current season’s growth and therefore need pruning hard in spring similar to Buddleja davidii.

Other Hydrangeas are climbing plants such as H. petiolaris with its heart-shaped leaves which turn yellow in autumn and lovely, flattened, white flower heads of both  small, fertile and larger, sterile flowers. These need little pruning but after flowering can be reduced back to fit their allocated space if required.

Another good garden Hydrangea is H. arborescens of which H. arb. ‘Annabelle’ is probably the most widely grown. This has ovate, serrated leaves and large, up to 1ft (30cms) across, spectacular, rounded heads of white, sterile florets.

The next three plants are in the main herbaceous perennials grown for their summer flowers and are all in their different ways excellent garden plants. Echinaceas or Coneflowers are one of several daisy-like flowers which grace our summer gardens. The botanical name comes from the Greek word for ‘hedgehog’ or ‘sea urchin’ (echinos) which resemble the spiky, central cone of the flowers. The genus is quite small with only around 9 species in the wild found in dry prairies, gravelly hillsides and open woodland in central and eastern North America, however, these have been joined in the last fifty years by hundreds of new cultivars. The daisy-like flowers which are generally white, pink or purple are a nectar-rich favourite of bees and butterflies and their spiky seed cones which mature from orange to black offer winter texture and structure as well as food for birds. They stand well in rain and wind, tolerate quite poor soils and flower over a long period. However, some of the older cultivars are rather short-lived perennials and this is a drawback which plant breeders have been keen to overcome in the last twenty years or so.  With this in mind the RHS have recently completed a four year trial of 142 recent Echinacea cultivars and of these 9 were awarded an AGM (Award of Garden Merit) being judged on weather resistance, longevity, quantity of flowers and length of flowering period. The award winners were:-

Echinacea ‘Leilani’- a yellow cultivar up to 1m tall

1. E. ‘Butterfly Kisses’- a compact, bright pink cultivar similar to a Zinnia
2. E. ‘Glowing Dream’- also compact (50cm) with many, large purple-red flowers with orange cones
3. purpurea ‘Green Jewel’- slightly taller at 80cm with pale green petals and a yellow cone turning orange with age
4. E. ‘Pink Shimmer’- up to 1m bright pink, scented flowers and orange cones
5. E. ‘Secret Affair’- with deep pink, double, pompom-like flowers up to 80cm
6. purpurea ‘Virginia’- up to 80cm with white, scented flowers

The eighth cultivar has yet to be named and the ninth winner was an older cultivar which had its AGM reconfirmed- E. purpurea ‘Elton Knight’- up to 80cm with pink petals, the classic Echinacea flower shape, highly scented and loved by bees. At least three of these cultivars are related to an old favourite, Echinacea purpurea, which is in itself a botanical marvel. Each flower head begins as a tight bud of lime-green that daintily blushes pink then opens as a giant of a daisy with shocking-pink ray petals around a contrasting brown centre.  As the flower opens the central cone grows in size, becoming tinged with flaming orange and the ray petals relax downwards, fading reluctantly but refusing to fall. If left to its own devices the cone finishes the season dramatically, transforming into a hard, dark urchin of seeds.

Next we have the simple yet elegant Erodium, also known as Heron’s Bill or Stork’s Bill after the shape of their seed heads. It is this seed head shape and the fact that Erodium flowers all have five petals that clearly put the genus in the Geranium family. There are around 60 species of annuals, perennials and both deciduous and evergreen subshrubs found in rocky habitats in the mountains of Europe, Central Asia, North Africa, North and South America and temperate parts of Australia. They are valued for their attractive foliage and long flowering period. The flowers range from pink to purple with occasionally yellows and whites many with attractive darker veins, lines or blotches. They clearly resemble Geranium flowers except that they have five, not ten, stamens. Erodiums are generally much smaller, and some would say, neater than most Geraniums and are used mainly in rock gardens, troughs and at the front of herbaceous borders in a sunny position and in a very well-drained, gritty soil or compost. Below are some of the favourites of Helen and Andrew Ward of Norwell Nursery in Newark, Nottinghamshire.

Erodium ‘Purple Haze’- a low, spreading mound of divided, silver leaves. Flowers are lilac-pink with dark purple blotches on the two upper petals. A good starter plant for those new to Erodiums flowering in June and July

E. x kolbianum ‘Natasha’- a very similar plant but one which flowers from May to October

E. ‘Princesse Marion’- a larger, upright cultivar with fresh green, ferny foliage and deep pink, heavily veined flowers with paler markings on the two upper petals

E. x lindavicum– a white hybrid with brown veining and silver-grey foliage flowering freely from May to July

 Finally we come to the lovely Helenium– Helen’s Flower or Sneezeweed. These are from the same family as Echinacea- Asteraceae or Compositae so are basically another daisy. The genus is comprised of about 40 species of annuals, biennials and perennials found in damp meadows or woodland margins in North and South America. They are popular garden plants as their flower heads are among the most richly coloured of the daisies with prominent yellow or brown central discs and ray florets in yellow, bronze, orange or red. They flower for long periods, are attractive to bees and are suitable for a sunny, mixed herbaceous border. A widely grown dark, copper-red cultivar is Helenium ‘Moorheim Beauty’ and a good yellow, overlaid with dark orange and with darker orange-brown central discs is H. ‘Wyndley’. Helenium ‘Bruno’, a good red with a yellow and brown centre, is also widely grown. As with Echinacea the best method of propagation is by division in spring or autumn.

I hope that this month’s featured plants will inspire you either to keep growing them or to try growing them for the first time. They will certainly add colour and interest to your late summer beds and borders and encourage more pollinators into your garden. It would be great to see you at our August talk on Saturday the 6^th at 9-30 am in the Tearoom when I will be showing off some of these great plants and discussing any gardening questions raised on the day.

Next month’s blog and talk will be highlighting some more late-season plants including Japanese Anemones, Rudbeckias, Asters and Grasses.

Until then stay well and enjoy your summer garden.

Keith.