Plant Conservation Centre

The Plant Conservation Centre (PCC) is one of the few National Trust properties not open to the public. In fact, its location is a closely guarded secret – and with good reason. The PCC is both repository and production site for many of our most valuable plants, the horticultural crown jewels that are as much a part of the history of a place as its wallpaper and furniture. 

Unlike the collections in our houses, plants don’t live for ever and require ongoing propagation and replanting to conserve their unique qualities. Many of these special plants are irreplaceable by the usual nursery sources due to their distinctive unique genetic make-up or unique horticultural heritage.

Protecting the irreplaceable

In order to protect these plants the PCC follows rigorous biosecurity procedures. Any incoming plants are held and carefully monitored in a separate quarantine facility, and even staff members have to pass through a foot-scrubbing and disinfection point before entering the plant areas.

With just three members of staff, the centre provides a service to Trust gardens and parks all over England, Wales and Northern Ireland. Wherever a special plant is identified as being under threat, the centre’s expert propagators are called upon to help, using a range of techniques both traditional and state of the art. In most cases the aim is to produce offspring identical to the parent plants. Simply collecting and growing from seed can introduce uncertainty and variety, and a loss of the original appearance or genetic inheritance. Other ‘asexual’ methods are therefore needed to produce cloned copies of the parent.

Cultivating the next generation

The most commonly used technique is grafting. Cuttings are taken from the plant to be propagated and attached, or grafted, to the roots of a compatible plant (the rootstock). This is how named apple varieties like Bramley are grown. Many of our most significant historical landscapes such as Wimpole Estate in Cambridgeshire rely on grafted trees to replant avenues of limes and other species.

Successfully propagating some plants often takes persistence and experimentation, especially where old or ailing plants are concerned. The centre’s manager, Chris Trimmer, has even invented a special pipe-warmer to speed up the process of grafting new plants.

The Plant Conservation Centre has propagated some of the rarest and most historically significant plants in the Trust’s gardens. Here are a few examples:

‘Newton Wonder’ apples at Woolsthorpe Manor, Lincolnshire

Said to have inspired Sir Isaac Newton’s theory of gravity, this famous cultivar still grows at his home, Woolsthorpe Manor. It’s been propagated at the centre as part of the Orchard Project, a project to protect endangered apple tree varieties.

Knightshayes gentian

Many plants end up growing at a particular garden through friendships and chance events. One such is the beautiful blue alpine willow Knightshayes gentian (Gentiana asclepiadea ‘Knightshayes’). This particular variety came to Knightshayes through the efforts of avid gardener Nellie Britton. She lived in the village and encouraged her neighbours to plant their burgeoning alpine beds. Her enthusiasm for plants, especially alpines, is said to have inspired Knightshayes’ owners, the Heathcoat Amorys, to create their garden in the first place, so her gift of this unusual pale-throated willow gentian is particularly significant.

Dozens of Knightshayes gentians have been raised at the PCC and distributed widely to other gardens to help ensure the variety’s survival.

Leonard Messel’s seedling  ‘Nymansay’ at Nymans, West Sussex

The garden at Nymans is a treasure trove of horticultural rarities. Much of the garden’s planting was initiated by Leonard Messel, a knowledgeable plantsman and sponsor of plant-collecting expeditions. The acquisitive habits of Messel led to the planting of many new species, including Eucryphia from the mountains of Chile.The garden is now home to a rare hybrid ‘Nymansay’ (E. x nymansensis ‘Nymansay’). This beautiful large shrub has gained a wide reputation for its lush foliage and gorgeous summer flowers.

Although the original ‘Nymansay’ died some years ago, it has been replaced with young plants raised at the PCC to ensure its horticultural legacy continues. These ‘chips off the old block’ can be seen flowering in late summer in various parts of the garden.

The rhododendrons of Rowallane Garden, County Down

Rowallane in County Down is home to many rare rhododendrons thanks to the avid 20th-century collector, Hugh Armytage Moore. He spent over 50 years filling the 21-hectare (52-acre) garden with an amazing diversity of rare plants, including a dazzling range of rhododendrons. Luckily, he also kept meticulous records so we have a good idea of the garden’s former horticultural glory and can replenish it with species collected by Moore.

Many of the rhododendrons are unusual Asian species such as Rhododendron euchroum, introduced from Burma by plant-hunter Frank Kingdon-Ward in 1914. This very rare plant was rediscovered in the garden in 2009 and has since been propagated and replanted.

Cedars of Lebanon at Croome Park

Cedars of Lebanon are an essential part of the landscape at Croome Park but have fallen into decline due to the attrition of age and disease. When it came to replacing these trees, we wanted to source them from the wild to support the conservation efforts of the International Conifer Conservation Programme. Trees grown from seed from surviving populations on Mount Lebanon were raised at the PCC and planted in the parkland in 2016. It will be many decades before these trees step up and play their full part in the landscape, but in the meantime they are fulfilling a dual role of conserving heritage and helping to ensure the continuation of this beautiful conifer.