On a legal note, before you remove any shrubs/plants from the garden, you should let your prospective buyer know that you will be taking them. Plants in the garden are like 'fixtures and fittings' in the house.
Unless they are stipulated in the Contract, you will not be able to remove them.
I know of a case where the vendor of a house dug up and took away their rose garden. The purchaser complained that that was one of the features that persuaded them to buy the property. The vendor had to return them to the purchaser.
I don't suppose it did the roses a lot of good, but when moving house, and wanting to take plants with you, it is advisable to do it legally.
valmarg