Grecian horehound

A compact, mounding deciduous shrub bred in the 1930s by crossing the East Asian species Caryopteris incana (southern China, Taiwan, Korea, Japan) and C. mongholica (Siberia, Mongolia, northern China) - it has no wild range of its own. Its defining virtue is a flush of vivid blue-to-violet flowers on the current year's growth in late summer and early fall, a period when little else in the garden blooms, combined with aromatic gray-green foliage and exceptional drought tolerance once established. The honest catch is its borderline hardiness at the cold edge of its range: in zones 5–6 the woody stems routinely die to the ground in winter and the plant resprouts from the base each spring, behaving more like an herbaceous perennial than a shrub - gardeners in those zones should hold back pruning until new growth confirms the crown has survived.

A dwarf, evergreen Mediterranean sub-shrub with intensely aromatic silver-grey needle-like leaves and clusters of small, long-lasting yellow button flowers in summer. Native to the dry, rocky ground of the western and central Mediterranean basin, it is prized for its bold textural foliage and the illusion of a curry scent - although the plant has no culinary relationship to curry spice and its flavor largely disappears on cooking. The honest catch is hardiness: Helichrysum italicum is reliably winter-hardy only to about USDA Zone 8 (around 10°F); in colder climates it either dies outright or must be overwintered frost-free, and even within its range it is short-lived on heavy, wet soils where winter root rot claims it quickly.

Heather, or ling (Calluna vulgaris), is the low, wiry evergreen shrub that colours the moors and heaths of Europe purple in late summer. It grows only 4 inches to 24 inches tall in dense, spreading mats of tiny scale-like leaves, and from July to September it is covered in spikes of mauve (wild) to white, pink, or red (cultivar) flowers that draw an intense traffic of bees - the source of prized heather honey. It is beautiful, wildlife-rich, and extremely cold-hardy, but it is also a fussy plant with two non-negotiable demands: genuinely acidic soil and cool summers. The honest catches: it will not thrive on chalk or in hot, humid heat (NC State advises against planting south of zone 6), and where introduced - notably New Zealand - it has become an invasive weed.

Trailing lantana (also called weeping lantana, purple trailing lantana, or creeping lantana) is a low, sprawling evergreen shrub or subshrub from southern South America - Uruguay, Paraguay, northern Argentina, Bolivia, and southern and eastern Brazil - named for Montevideo. Unlike common lantana (Lantana camara), an upright shrub with multicolored heads, it stays 12 to 18 inches tall and spreads 3 to 5 feet on vine-like stems, making a mat of dark green, coarsely toothed leaves covered in small clusters of lilac to purple-pink flowers with yellow throats from early summer to frost, and almost all year where winters are frost-free. It is winter hardy only in USDA zones 8a-10b (in zone 8 it dies back to the ground and resprouts in spring if well mulched) and is grown as an annual or container plant in colder regions. Two cautions come first. It is poisonous: NC State Extension rates it medium severity, with toxic fruits, leaves, sap, seeds, and stems, toxic to people, dogs, cats, and horses, and Weeds Australia reports it is suspected of poisoning cattle. And it escapes gardens: NC State Extension records it naturalized in the southern United States, Hawaii, New Zealand, and eastern Australia, Weeds Australia lists it as a declared weed in Queensland, New South Wales, the Northern Territory, and Western Australia, and the UF/IFAS Assessment of Non-native Plants predicts it to be invasive and does not recommend it anywhere in Florida.

An old garden-favorite annual native to Mexico, grown for showy daisy-like flowers in nearly every color but true blue - red, yellow, orange, pink, rose, lavender, green, and white. Bushy, leafy plants rise on upright, hairy, branching stems and bloom continuously from early summer to frost. A magnet for butterflies and hummingbirds, and one of the most reliable cut-and-come-again cutting-garden flowers.

Jasmine tobacco, also sold as flowering tobacco, sweet tobacco, or winged tobacco, is a tender perennial in the nightshade family (Solanaceae) native to southern and southeastern Brazil, Paraguay, Uruguay, and northeastern Argentina. The true species grows 3 to 5 feet tall from a low rosette of large, hairy basal leaves with winged stalks, and from early summer to frost it carries long-tubed, star-faced flowers, white to greenish-yellow, that open in the evening and pour out a sweet scent through the night for moths. It is perennial only in USDA zones 10a-11b, so most gardeners grow it as a summer annual. Many plants sold as 'flowering tobacco' are compact hybrids (Nicotiana × sanderae and similar strains) up to 24 inches tall whose flowers open by day and are mostly unscented; for the night fragrance, grow the species from seed. Be aware that it is poisonous: every part of the plant contains nicotine, it is harmful if eaten, and the RHS advises gloves when handling it.