The Iris Walk at Chartwell
When the Campbell-Colquhon family lived at Chartwell, the 80m long narrow border below the main terrace wall was originally an herbaceous border. When the Churchills moved in it was subsequently simplified to mostly bearded iris, a flower loved by Clementine Churchill, and hence became known as the Iris Walk.
Lady Clementine’s Irises
Breeding new colour combinations of iris became popular in the 1920s and 30s, with notable British breeders leading the way, and the Churchills acquired what would at the time have been an unusual and varied collection.
Although bearded irises are beautiful plants, they have a relatively short flowering period in May and June, so in 2018 a new scheme was designed to extend the season of interest into the summer and autumn whilst still leaving the irises as the star of the show earlier in the year.
The first task was to identify the irises already in the border. Lists of irises recorded as being in the garden in the 1930-40s and 1990s were used to discover the different types, including ‘Lord of June’, ‘Grace Sturtevant’ and ‘Mrs Alan Gray’ – all from the Churchills’ time at Chartwell.
The Garden Team also worked closely with nearby National Trust Sissinghurst Castle Gardens, where Helen Champion, who looks after their bearded irises, has carried out extensive research about Sissinghurst’s collection originally started by Vita Sackville-West. Helen has hunted down some of the “lost irises” from the Sissinghurst collection and has a dedicated area in the cutting garden where she is carefully nurturing historic varieties to provide additional plants for the garden.
One of the Churchill era iris varieties ‘Corrida’ - which, like many of the older varieties, is no longer commercially available – was found by one of the team and Helen is now “bulking up” her own stock so that she will be able to provide Chartwell with some rhizomes to add to our own collection.
The gardeners at Polesden Lacey are involved in a similar project and they too have shared some of their historic iris varieties with us at Chartwell.
Where it has not been possible to track down the original varieties, other irises from the same era and fitting with the soft pinks and pastel colours preferred by Clementine Churchill have been added.
Planting the new border
Once the irises had been sourced and a planting plan had been drawn up, we began work on replanting the border. Over the years the border had lost its straight line as shrubs grew out from the wall and so we carried out some renovation pruning on the large Magnolia grandiflora and Laurus nobilis, before creating a straight edge and filling in the gaps with new turf.
Herbaceous plants and those with contrasting foliage colours and textures have also been included into the border. These will continue to flower after the irises have gone and keep the border looking lovely throughout the summer. Some of the included plants are Nepeta ‘Walker’s Low’, Ballota pseudodictamnus and Artemesia ‘Powis Castle’. All of the plants chosen are drought tolerant as the soil along the Iris Walk is poor, stony and very dry.
Caring for bearded irises
Bearded irises prefer a rich, alkaline or neutral soil that does not get too wet in winter. However, the most important way to achieve good flowers is to make sure they are planted in full sun so that the rhizomes can be ‘baked’ for as long as possible. They also need to be planted where they will not be shaded by other plants.
When planting, the rhizome needs to be placed shallowly so that it is still visible on the surface and not covered by soil, ideally with the length of the rhizome facing south and with each plant around 10cm apart.
After flowering, each bloom can be snapped off leaving the next bud to flower and once flowering has stopped altogether, the stem can be cut or snapped off at the base. Once the display is finished, the leaves can be cut back to a fan shape of about 5cm tall. This reduces shading on the rhizomes in the height of summer and new fresh leaves will soon emerge.
As irises age they become crowded and flower less, so it is a good idea to lift and divide them every 3-5 years. The best time to do this is after flowering as they will put on the most root growth between July and September. Any old, rotten pieces of rhizome can be snapped off and pieces of about 7-10cm long retained for replanting.
The leaves should then be cut back to a fan shape to avoid windrock and replanted with the roots spread out below the surface and the rhizome exposed on the top of the soil. They then need to be watered in for the first few months in dry weather until the roots are established.