Garden centre needs are already being met says chairman.
Bob Gault, chairman of Klondyke garden centre, is reportedly planning to lodge an objection against Dobbies' proposed garden centre site at Orton Grange, near Dalston, Carlisle.
Mr Gault feels that as Klondyke had to prove there was a 'need' for Houghton Hall's eastern site, the same rules should apply for Dobbies' latest application.
Mr Gault told The Cumberland News: "We employed consultants to do that. Having established there was a need, we built a garden centre to satisfy that.
"It is going to be difficult now for somebody else to do the same."
Dobbies' Carlisle complex, which will sit on the western edge, would include a farm foodhall, restaurant and specialist aquatics department. It hopes to open the centre in March 2010
In a separate move, Klondyke has acquired Lady Green Garden Centre at Ince Blundell on the outskirts of Liverpool.
This takes the total number of garden centres operated under the Klondyke and Strikes banner to 24.
The owners, Philip and Sue Allison are to retire from the business but their son, Richard and his wife Katie will remain.
Lady Green – in the North West since 1986 – is set in 10 acres of landscaped grounds. It has sales of more than £4m; there is a covered retail area of more than 30,000 sq ft.
Only this year Lady Green celebrated winning GCA awards: Best Outdoor Plant Area in the UK, and best overall centre in the North West.
On a national scale it ranks seventh in the UK, according to the Garden Centre Association.