The slanting sunlight of late summer and autumn makes magic out of plants with colorful leaves. At this time of year, bold-leaved tropical or tender plants, such as coleus, croton and cockscomb, have reached substantial size and their leaf quality is still excellent, given warm daytime temperatures. Meanwhile hardy shrubs and trees will be beginning to show fall foliage colors.
To highlight the colorful leaves in your late summer and autumn garden, try placing plants that bloom late and in shades of blue adjacent to those foliage plants. Here are a few options for late-season blue flowers:
Bluebeard (Caryopteris), a compact hardy shrub with frothy blue end-of-summer flowers. Some cultivars, like La Barbe Bleue, also show vivid foliage color of their own.
Perennial plumbago (Ceratostigma plumbaginoides), a hardy perennial ground cover with vivid blue flowers from midsummer into fall.
Autumn-flowering California lilac, such as Ceanothus 'Burkwoodii', hardy to USDA Zone 8 and blooming from late summer into fall with rounded bright blue flower heads.
Mealycup sage (Salvia farinacea), a perennial in regions as cold as Zone 8, grown as an annual elsewhere. It puts up spikes of blue flowers from spring until frost.