She was speaking at the International Horticultural Forum at IPM Essen, which had the UK as a partner country this year.
Paris said the NLW, which will rise to £7.20 per hour in April and £9/hr by 2020, is "a real challenge" that is "going to have a huge impact on growers in UK". She said "most growers are making four-to-five per cent profit and NLW is more than that for them in some cases".
Paris added that "some landscape companies are likely to be forced into administration" because they cannot change fixed contracts set before the NLW was announced, meaning margins have gone. Alternative energies and mechanisation need Government incentives because oil companies are not investing due to cheap oil.
Paris said venture capitalists are in the market for the short term of three-to-five years and are "more interested in the price than long-term relationships", while new entrants such as B&M and Waitrose are looking for more long-term contracts, which will help nurseries gain guaranteed income to invest in technology to beat the NLW.
She outlined the Ornamentals Round Table action plan and Horticulture Innovation Partnership strategy, launched last month in Parliament, which aim to have the Government help increase competitiveness in the UK, among other "asks" and plans. This is an example of collaboration not seen before in UK horticulture, she added.
This is the "first non-gardening generation - generation rent" with the UK always having been a homeowning nation, but last year, for the first time, there were more renters than non-renters and "people not really wanting to develop their garden for landlords". She added: "That generation does not have the same level of gardening knowledge and skills as their parents before them."
Paris said she is looking for the Government to promote gardening while a garden expo, one of the action plan "wants" that may happen by 2024, is "getting quite a lot of traction as a showcase for UK horticulture and green infrastructure while leaving a lasting legacy as well as blueprint for a garden city".
She is also asking for more procurement of UK plants by public bodies, for instance HS2 trees to be ordered soon "so we haven't got the situation of having to look worldwide", adding that imported plants produce a plant health biosecurity risk, and the HTA is working with the Government on producing a plain English guide to plant health.
It is often "much quicker to buy plants from Holland for your garden centre than from the UK market", she said, and the new action plan aims to address that. Sunday trading law is "a very strange UK law" that needs to be changed, she added.
INDEGA general manager Harald Braungardt was chairman of the panel at IPM Essen. He said the issues facing UK and German/European horticulture are the same, with a lack of skilled workers and rising costs in a static market.
Commercial Horticultural Association chairman Pat Flynn said: "There's no doubt British horticulture is facing some of the most challenging times its ever had," with new diseases, NLW, floods, growers selling up for housing and overseas competition all issues. A higher NLW could make working in horticulture more attractive for UK workers, she suggested.
Also on the panel was Ed Marley from Whetman Pinks, Lindsey Reid from Guernsey Clematis, Paul Greenhalgh from PG Horticulture and Horticulture Week deputy editor Matthew Appleby.