Plants that caught my interest from The American Horticultural Society's "Plants for Places: 1,000 Tried and Tested Plants for Every Site, Soil, and Usage". I only focused on plants for clay soils and hedges.
Plants for Clay Soils:
Syringa Vulgaris "Congo"
This densely flowered from of the common lilac bears conical clusters of fragrant, lilac-purple flowers in early summer above hear-shaped, dark green leaves. Like other lilacs, it also thrives on well-drained soils, including shallow and alkaline, and it tolerates coastal sites and urban pollution. A fine backdrop for a shrub or mixed border. Little pruning is necessary. Learn more at Martha Stewart's online Home and Garden section.
Deciduous shrub. Full sun. Well-drained soil.
Vitis Coignetiae (also known as the Crimson Glory Vine)
This vigorous, woody stemmed climber has large, hear-shaped leaves that turn bright red in autumn; the color is best in full sun. It climbs using its tendrils and is ideal for clothing a warm wall, pergola, or large tree; if pegged down it also makes a good ground cover. It tolerates sandy and slightly alkaline soils as well. Prune in midwinter.
Climber. Full sun or Partial shade (either dappled shade or shade for part of the day). Moist soil.
Plants for Hedges:
Hedges are used to define boundaries, provide privacy, protect plants from wind, and to keep children and pets out of certain areas.
Taxus Baccata (also known as Common Yew)
A well-proven , coniferous hedge plant with small and linear, dark green leaves born on green shoots. Small red fruits may appear at the end of summer, although these are often clipped off. All parts of the plant are toxic except for the red, fleshy covering of the seeds. An excellent choice for topiary. It will grow in dry shade, and tolerates alkaline soils. It is one of the few conifers that can be cut back hard and recover. Trim in late summer or early autumn.
Evergreen tree. Full sun or Partial shade (either dappled shade or shade for part of the day). Well-drained or moist soil.
Buxus Sempervirens (also known as Boxwood)
Boxwood is very tolerant of clipping and well proven as hedging, edging, and topiary. The species has small, glossy green leaves. Trim hedges once a year in summer. Clip topiary twice a year from late spring to summer. Encourage new growth with a dressing of fertilizer and a surface mulch. Also good for alkaline soils and in shady containers.
Evergreen shrub. Full sun or Partial shade (either dappled shade or shade for part of the day). Well-drained soil.
Learn more about Topiary:
www.topiaryarts.com