Higher prices for raw materials, the threat of labour shortages and a weakened housing market are among the challenges identified by industry figures responding to a Horticulture Week review of the big issues facing sectors post Britain's decision to leave the EU.
Among the opportunities to be identified in the review, import substitution by UK growers was the most frequently cited, while weaker economic conditions could see money diverted from holidays abroad to gardens and garden visits and greater autonomy over plant-health issues could emerge.
A snap poll, meanwhile, revealed the depth of concern across the industry as a whole at the uncertainty triggered by the surprise vote for Brexit on 23 June.
Of 200 responses from a range of sectors to a HW poll, 65 per cent were less positive about prospects for their sector short term, with just 18 per cent more positive and 17 per cent undecided. Some 57.5 per cent were less positive about prospects long term, 30 per cent more positive and 12.5 per cent undecided.
There was greater concern from the amenity and landscape sectors than in production horticulture, with shortage of workers and potential recession voiced as downsides and the possibility of more import substitution and better plant biosecurity cited as reasons for cheer.
More respondents contributed downcast comments than upbeat, with one grower saying: "I cannot help but feel this will be a disaster for the horticultural nursery and landscaping sector given the amount of trade with Holland, Belgium and Italy."
Another horticulturist said: "There is a real danger of losing all the environmental protections we've worked hard for 40 years to secure."
A maintenance gardener wrote: "I'm struggling to think how we'll survive if we lose our non-UK workforce. We simply can't find UK workers of the right type." However, others expressed hope for more positive outcomes. One said: "Expect massive opportunity to grow more plants in the UK instead of importing them from Holland."
Defra and industry bodies have said there will be no change in the short term, at least until Parliament returns from recess on 9 September and a new prime minister is appointed along with a new Cabinet. Only then will new trade deals start to be discussed.
One typical response was: "I suspect many projects will be put on hold and less confidence in spending on private and public areas as probably prices will go up on most things and construction also needs free movement of labour."
Another respondent commented: "The uncertainty of what these issues will be is going to have a negative impact on potential investment in the sector. A large part of our business is with EU countries and we are already seeing a drop from the continent."
Garden designer Andrew Fisher Tomlin pointed out that he has had four City worker garden design projects put on hold. "There will be a talent drain," he said.
The UK imports £1bn of plants a year but exports just £50m. One respondent said: "We need growers to begin plugging the gaps in production that are filled by imports. There is an opportunity for the sector to grow the imports side of business with the weakening pound."
Immediate impacts, apart from cancelled landscaping jobs, include retail prices of imported goods rising because of sterling weakening and one grower, Hayloft Plants, cancelling a move to new premises because of the uncertainty.
Garden retail supplier Gardman suggested prices might rise 15 per cent in wholesalers' catalogues published for Glee in September.
Commenting on potential price rises, Mr Fothergill's Ian Cross said: "In the short term it will do looking at the state of exchange rates. But like everyone else I have no idea longer term. About 80 per cent of what we sell is bought in dollars or euros. The worst thing is the uncertainty."
HTA chief executive Carol Paris said: "We are still in the EU and bound by the same regulations for a minimum of two years, realistically likely to be more. There will undoubtedly be price fluctuation while the currencies move but this will hopefully settle down."
Majestic Trees' Steve McCurdy said: "The big plus for me is pests and diseases. (Chief plant health officer) Nicola Spence can introduce fair and reasonable controls. I hope she rates different nurseries one-to-three stars across Europe and that will dramatically reduce pests coming in."
Rolawn's Jonathan Hill added: "The housebuilding industry seems to be slowing down but people still need places to live - and in a recession, if there is one, people invest in their properties."
NFU horticulture adviser Amy Gray said the NFU will work to reduce barriers to trade. Defra horticulture team leader Kathleen Kelliher added: "Nothing changes for the next two-plus years until Article 50 is signed. There will be opportunities as well as issues and we've got a few years."
- See also Mark Glover's Brexit analysis.
RISKS AND OPPORTUNITIES - Sector-by-Sector
HW Brexit poll
Poll respondents comment
As a maintenance gardener in London, I'm struggling to think how we'll survive if we lose our non-UK workforce. We simply can't find UK workers of the right type ... Expect massive opportunity to grow more plants in the UK instead of importing them from Holland. Just hope growers here can step up to the mark ... The soft-fruit sector will require access to fruit pickers from abroad. Would suggest the setting up of a group of horticulture consultants to help the NFU during the next two years ... I export to Europe so think there will be a backlash against buying British goods ... We rely on plants from the EU (mainly Netherlands) and would be concerned about higher prices and lack of common regulations relating to free movement of goods ... Free trade/movement of plant material will be made more difficult ... The threat of EU controls will cease ... Without a common framework for regulations surrounding pesticides manufacturers will end up having to deal with greater complexity, which might delay approvals in the UK while they concentrate on the EU and increase costs ... Real danger of losing all the environmental protections we've worked hard for 40 years to secure ... We can make our own decisions about chemicals etc ... We need growers to begin plugging the gaps in production that are filled by imports. There is an opportunity for the sector to grow the imports side of business with the weakening pound ... Suspect many projects will be put on hold and less confidence in spending on private and public areas as probably prices will go up - construction also needs free movement of labour ... In terms of ornamental and edible production the sector is reliant on migrant workers and therefore we need them to produce at a sustainable level ... Separating the functions of Britain and the EU will produce some difficult issues - the uncertainty of what these issues will be is going to have a negative impact on potential investment in the sector ... An excellent opportunity to increase UK produced plants ... We might have a 'buy British' attitude getting stronger ... Costs increased due to currency fluctuations, weaker economy, investment decisions cancelled by some clients ... Worried about less investment, shrinking economy and less construction ... Uncertainty means people are less likely to invest in their gardens ... New projects will go on hold due to the fall in share value and expectation of higher borrowing costs ... Short term we are very busy and the vote seems to have mode no difference to the flow of enquiries ... The long-term impacts of Brexit will not be realised until the negotiations have been completed for Britain's exit. The best option for our sector is to engage with the negotiations and make whatever is agreed work ... A future bonus area is plant health, where there are variable standards of inspection and enforcement in certain customers. Price rises usually result in caution in initially ordering and decreasing demand