Would you consider using it purely for access for ensuring the hedge stays 'reclaimed'? Youll be down there with the trimmer and hauling tarp at least once a year. Thick gravel as a topping, or flagstone paving with little niches between where small plants can catch the water before the hedge does, and some leaf mould can build up to improve the growing conditions in a micro way.

You may have found that a hard prune on the hedge has gone into old wood - so regrowth might not actually be an option - but the top will probably need keeping in order.

If the ground is suitable beyond the four foot reclamation area - would a series of arches for Clematis, honeysuckle, climbing roses, even 'tough it out' Wisteria (though your neighbour might not thank you!) help to make the area more pleasant? Even some of the annual climbers could work.

Vetivert8, what a pleasant surprise to receive your response, thank you so much. I had given up on anyone responding, but I think I did not clearly explain the situation. This 'thing' is a hedge by virtue of its being a row of cedars. It has never been trimmed or shaped into a true hedge and when we moved here the trees were already over 20 feet tall. I have reclaimed this 4-foot area by trimming all the lower branches of the cedars for a height of about six feet. I did get into hard wood so there will be no new growth either vertically or horizontally. A few weeks ago my neighbour on the opposite side of the hedge did the same on their side. We are now left a series of six-foot posts dividing the properties. So use of it as an entrance is not an option, and hence the arches would be inappropriate. I posted my question on another site and it was suggested that I make it a hosta garden with some other shade perennials interspersed, and I am thinking of going that route. Thank you for your interest and suggestions.
Northerner.