Liddell-Grainger said: "We know we are in a new world.We are going to go through turbulent times," post-Brexit, but said he would stand up for the industry even as retailers and suppliers clash over who will pay for price increases caused by sterling's crash that has followed Brexit.
The NFU has suggested extending the Groceries Code Adjudicator to include ornamentals as part of a consultation on the future of the GCA. The code oversees the relationship between supermarkets and their suppliers. Tesco recently refused to take increases from Unilever, while in the garden market suppliers are walking away from retailers who will not agree to wholesale price rises.
Liddell-Grainger said: "As a rural MP for West Somerset, I have got to stand up to these people like Tesco. If we know who they are, we must stand up to bullies. I will name and shame them in the House of Commons."
He added: "The vast majority of farmers and people in rural industries wanted out and we need to fight their battles for and with them."
The All Party Parliamentary Gardening and Horticulture Group annual reception is set to be funded by new sponsors, who say the lobbying event is too important to lose. Scotts Miracle Gro decided to pull out of the £7,500 sponsorship after several years of support.
HTA, RHS, BALI, Arboricultural Association and Landscape Show are set to club together to fund the 29 November reception at the Houses of Parliament.
Organisers Newington Communications (formerly Bellenden) hope Defra secretary of state Andrea Leadsom will speak at the event.
Liddell-Grainger said he was "not very surprised," by Scotts' pull-out, adding: "We'll find someone else."
He said on lobbying, which has also become more difficult after changes in Defra's civil service team to shift staff to Brexit roles: "Both the agriculture and horticulture industries have an enormous amount of friends in the House of Commons and House of Lords, people who are genuinely wanting to make sure after the referendum the rural community of Britain is truly heard where it needs to be, which is in Parliament.
"There is a very active ministerial team, a very active Parliament in both ends and we're under no illusion that one of the great success stories post-Brexit should be agriculture and horticulture."
- Sponsors are also in flux at Chelsea Flower Show, with Brexit being blamed by some. The Daily Telegraph and Brewin Dolphin are among those who have pulled out, with the Telegraph's commissioned design by James Basson now being built by Crocus for M&G, who are in the last year of eight as overall show sponsor.