You can take any plants you like unless they are on the fittings and fixtures list or they are intended to make a permanent improvement to the property (e.g. large trees, tall shrubs which provide privacy, plants intended to create shade like climbing plants on a structure, plants which firm part of a substantial landscaping scheme, Ivy climbing on the front of the house to improve the way it looks etc). That’s the legal answer anyway. But if you are intending on taking plants with you it’s good to notify your buyer to be polite.