A National Trust representative said: "With our ‘going local’ strategy rolling out a few years ago the emphasis is now on properties to source their own plants and for them to ensure suppliers meet our criteria which includes peat-free.
"The new HTA list when it comes out will help us to build a new list which properties will be able to access. The aim is for this list to be ready later next year.
"Work is going on to ‘refresh’ the list with more emphasis on properties to find their best local suppliers to provide peat free plants which they require and addition to anything that Hillier is supplying."
"The only plant supplier we manage centrally is Hillier and then our individual properties source plants from nurseries local to them who can supply peat-free."
Hillier is expanding supply for the 10 biggest to 27 National Trust properties in 2015. Prenplants supplies 31 properties, while the National Trust nursery at Lanhydrock is a big supplier of its plant centres.
Former National Trust gardens adviser Raoul Curtis Machin, who was involved in setting up the plant supply system and is now HTA horticulture head, said: "We’re collating the list for the National Trust. The deadline is in a couple of week’s time."
He said because National Trust properties tend to have limited storage space for plants and did not have purpose-built plant retail buildings generally, regular supplies are required. This led to weekly or fortnightly ‘base’ core plant supplies from Hillier, which make up around 20 per cent of stock at designated property’s plant centres. Plant buyers at each property can then look for local suppliers.
He said the Trust has large numbers of regular garden visitors, who often want a souvenir: "There is a lot of opportunity. One of the things we identified when I was with the National Trust was the huge potential for plant sales."