Hedge bottoms
Easily the most commonly asked question amongst our customers is "what can I plant under my hedge?" Sometimes its north facing, and hence completely in the shade, sometimes south facing, and hence completely arid. The hedge is usually conifers - surely the hungriest, thirstiest most soil impoverishing plant in the world.
All in all, a pretty challenging environment for any plant, and frankly, there aren't many plants of any interest that are going to thrive in those conditions. The best you can really expect is some reasonably attractive ground cover, and perhaps the occasional flower.
Anyway, for your delectation, here is our list of possible candidates:
Ground cover, shade
Ajuga
Bergenia
Convallaria
Cotoneaster dammeri
Epimedium
Euonymus
Euphorbia
Gaultheria procumbens
Geranium
Hedera
Heuchera
Omphaloides
Pachysandra
Polystichum
Sanguinaria
Tiarella
Tolmeia
Trachystemon
Vinca
Other plants for dry shade
Asplenium
Bergenia
Dryopteris
Euonymus
Galanthus
Geranium
Hedera
Helleborus
Iris
Kerria
Lamium
Rubus
Ruscus
Eleagnus
Skimmia
Sarcococca confuse
Corydalis
Dicentra
Liriope
Luzula
Hedge bottoms with some sun
Campanula
Anemone
Crocosmia
Aquilegia
Euphorbia
Myrrhis
Lysimachia
Symphytum
Dryopteris
Athyrium
Polystichum
Brunnera
Vinca
Tanecetum
Senecio
Remember that whatever you plant, these are very challenging conditions, and the plants performance will vary depending on exactly how dry / shady / impoverished your particular border is. They will not necessarily look as good as they do on the nursery/in the books!
Also remember to give them lots of TLC to settle them in during their first few months in the border - they'll need all the help they can get to settle in to such harsh conditions.