Gardeners think alike :-)

I assumed that Lady Russell was going to be choosing some plants to keep as well. I kind of thought this was in reference to earlier in Ch. 3 when Sir Walter said:

"...but what restrictions I might impose on the use of the pleasure-grounds is another thing. I am not fond of the idea of my shrubberies being always approachable; and I should recommend Miss Elliot to be on her guard with respect to her flower-garden."

Mr. Shepherd does not actually agree to this, but instead says: "...there are established usages which make every thing plain and easy between landlord and tenant. Your interest, Sir Walter, is in pretty safe hands. Depend upon me for taking care that no tenant has more than his just rights."

It was probably not possible, or maybe even unheard of, to insist in the lease that their tenants not walk around the grounds of the house they had rented, but maybe uprooting some of the plants (or giving away plants in large pots?) was a way of Sir Walter and Elizabeth still having 'control' in that situation.