Im planning on planting red robin hedging in a border area created in a paved driveway..question is when paving was removed there is approx 150 to 200mm of hardcore remaining with original soil underneath - total area of new border is approx 8 sq/ m...red robin plants i will be buying will be potted and be 2 feet tall...can i just dig out a reasonable size area down to soil for each plant, back fill around plant with fresh soil & compost ? would they grow with this method ?