Sissinghurst’s head gardener Troy Scott Smith guides us through the jobs that he and his team do in spring. Images by John Campbell

By

Published: Thursday, 13 June 2024 at 10:45 AM

---

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.

You may also like

• Troy Scott Smith on his vision for Sissinghurst
• How the gardeners keep Sissinghurst looking great all summer
• Six gardening jobs for spring
• The head gardener at Sissinghurst on not watering the borders
• 15 of the best roses from Sissinghurst
• Inside the Delos garden at Sissinghurst

Seven 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