June at Sissinghurst arrives in a blaze of soaring spikes of lupins, peony buds, cow parsley and poppies dance in excited fecundity. For three weeks in June, the air within the crumbling walls of Sissinghurst hangs heavy with the intoxicating scent of roses.
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Key gardening jobs for summer
Add hardy annuals
Each week from February to midsummer we add plants to enrich and enliven schemes. Some, particularly perennials and shrubs, are planned, but others, such as the annuals, are more instinctive. Hardy annuals can be sown directly in their flowering site and then left to self-seed in subsequent years. Alternatively, for more control, we sow some hardy annuals in a pan under glass in September to October and again in February to March.
For each of the ten Sissinghurst ‘rooms’ we have a palette of annuals I’m happy to let run, simply weeding out the ‘enthusiasm’ of some, such as campions or poppies. Alongside firm favourites I like to try a few ‘new to me’. This year I’m growing the Chinese forget-me-not, Cynoglossum amabile ‘Firmament’. I am hopeful its indigo-blue flowers on light-limbed chocolate-coloured stems will be a delight threaded through bearded irises.
Tie in clematis
When growing clematis against a wall, the best method of support is pig mesh, the sort of wire that has 15cm squares, secured to the wall. Even with the right support, however, it is still vital at the start of the season to guide the new shoots in the direction that you want, using ‘twizzlers’ (paper-covered wire). Without this early intervention they will wrap themselves into a knot. One of my favourites is Clematis tangutica. A vigorous but never rampant clematis, it clambers over everything, hanging its yellow flowers like tiny Chinese lanterns. These flowers mingle with the silky silvery seedheads that Vita delightfully described as ‘reminding her of Yorkshire terriers curled up into a ball.’
Here's how to prune clematis
Deadhead roses
Deadheading is a weekly task during the flowering period. In the photo, right, I tackle striped Rosa ‘Honorine De Brabant’ with yellow Rosa ‘Claire Jacquier’ behind and surrounded by Rosa ‘William Lobb’, the rare Rosa ‘Magenta’ and an unknown pale-pink rose. We are lucky to have small teams of local volunteers who come in specifically to deadhead our roses. For every perfect bloom, there will be another two or three that have finished and will be unsightly unless removed.
Here's more on myth-busting rose tips
Sow biennials
We grow most of our biennials in a large open bed west of the Rose Garden. We sow under glass from the end of May into June, depending on the year. However, there are subtle timing differences that matter – the first you should sow are sweet Williams, followed by foxgloves, verbascum, wallflowers and pansies last of all, perhaps as late as July. When they’re large enough to handle, we prick out the seedlings into plug trays before lining them out in the biennial bed for summer. By the time we’re ready to plant in the garden, usually late October, the majority have made good strong plants and will flower from April through to June the following year.
Prune early flowering shrubs
Pruning in any garden is essential, but especially in more compact gardens. Sissinghurst is a series of small garden ‘rooms’, so I find the sense of order, definition and scale that pruning injects invaluable. I’m careful, however, to ensure that our pruning still allows the plant to grow beyond horticultural perfection. For me, the character of Sissinghurst is conveyed as much, if not more so, through the management of the plants, rather than the choice and distribution of them. So only prune what is necessary and be sympathetic and sensitive to the plant’s underlying character and form.
Lifting and dividing bearded iris
In 1949, Vita wrote of irises: ‘No velvet can rival the richness of their falls; or, let us say, it is to velvet only that we may compare them.’ Depending on the heaviness of your soil, flowering can become shy and so every three years or so we try to lift, divide and replant the entire group. Irises make their major root growth between July and September, so the best time to lift is immediately after flowering. Break away and discard all but the fattest rhizomes and cut the foliage to a low arrow-shaped fan. These should be re-planted in prepared soil at about 30cm spacing.
Here's more on caring for bearded irises
Cutting down early flowering perennials
By August the garden can look prematurely ‘over’, with the brown foliage of early flowering perennials exerting a negative influence. To avoid this, we cut any perennials that flower before midsummer’s day down to the ground as soon as they have finished flowering. Given sufficient moisture, new growth and some new flowers will soon reappear. A word of caution, however: by cutting some of these early doers down – for example, Iris sibirica – you are removing growth that might develop into attractive and sculptural seedheads that will both give interest to the winter garden, and provide a valuable food source for birds.
Ordering bulbs
Bulbs are generally despatched three times a year: spring-flowering bulbs in September/October; summer-flowering bulbs in February/March; and late summer/early autumn-flowering bulbs in August. Consequently, you need to be on watch as to when the various types should be ordered. I set myself a deadline of 1 August for ordering spring-flowering bulbs, so I can be sure I’ll get my chosen varieties before they sell out.
Try not to buy on impulse. Too many times I have bought like a child in a sweet shop and then regretted it – with the bulbs rotting away unplanted in their bags. Be prepared for when your bulbs arrive. Take time to sort and allocate them into planting locations, labelling for future ease. Before planting we store our bulbs in a dry, frost-free and mouse-free shed.
Here's why we should be ordering organic bulbs
Sowing and growing biennials
There is something very satisfying about raising your own plants, whether from cuttings or seed. Biennials such as foxgloves and teasels are plants that produce leaves in the first year and in the second year flower, set seed and die. Biennials can be left to self-seed, but for greater control I find it is better to propagate seeds in pans each year. The principles of sowing are the same as that of the annuals, but the aftercare and timing are different. While most annuals are sown from January to April, biennials are sown in June, planted into nursery rows in August and placed in their final position in autumn.
Here's more on sowing biennials
Pruning apple espaliers
The fruit trees at Sissinghurst flower at different times. Plums stir into life in March, pears in April, and finally in May the swollen buds of apples rupture to reveal their delicate white blossom. During the summer, pruning consists of only shortening the side shoots to five or so buds to allow more light and air to reach the fruit. Use secateurs to shorten all side shoots coming off the horizontal laterals to 4-5cm (spur-pruning). This will stimulate flower and fruit buds for the following season. Every three years in winter, remove some of these old spurs with a folding pruning saw to allow room for the fruit to develop and ripen.
Staking
The ideal staking will gently support the plant, while still allowing it to take on its natural shape, form and habit. A certain amount of skill and patience is required and an intimate knowledge of each plant’s growth. Timing is everything: stake too soon and the support will be visible; too late and the stems will have collapsed into something resembling a curled-up Yorkshire terrier. I prefer to use hazel (Corylus avellana) for staking. Stakes should be of sufficient strength and size to support the plant, and be inserted when the plant has reached two-thirds of its ultimate height, pushing the stakes in to about 10cm above the plant’s head, and tying in. If you’ve left it late, like me with this sunflower, you can use a shorter stick at the plant’s base, to support it where it is weakest.
Plants can also support each other. In the past, I have used the stiff, upright stems of Verbena bonariensis to support Dahlia ‘Bishop of Llandaff’ and the stout Astrantia major ‘Buckland’ to support the herbaceous Clematis integrifolia ‘Rosea’.
Cutting back
As a rule, any perennial that flowers before midsummer’s day can, and should, be cut down to the ground as soon as it has finished flowering. Given sufficient moisture, new growth and some new flowers will soon reappear. If you leave these plants uncut then come August the garden will be looking brown, tired and over.
Hay making
In late summer we cut down the long grass in the Orchard to make hay for our tenant farmer to use later in the year, using a scythe, which cuts the flowers and grass whole. Once it’s cut, we turn the hay and leave it to dry for three to seven days, depending on weather conditions, before we collect it. This is important, not only because it gives insects the chance go back down into the turf but also because it allows wildflowers such as yellow rattle to shed their ripe seeds. Once the hay is dry, we collect it using rakes and hessian sheets to make traditional hayricks, then use a harrow tool to open bare patches of soil, so seeds can re-populate the meadow.
Pruning wisteria
You can remove the spent flower spikes of wisteria (simply snip them off at the base) but at this time of year, the key thing is to remove the long, leafy new growth that is taking the energy and light from the developing buds that will flower next spring. Cut the new growth back by around two-thirds, to a length of around seven inches. An easy rule of thumb is to remember to cut back new growth to seven inches (around 18cm) in the seventh month.
Here's more on summer flowers to plant
