Round kumquat

The classic garden nasturtium - a fast, easy annual grown for showy, long-spurred, funnel-shaped flowers in red, orange, yellow, and cream above round, shield-shaped (peltate) leaves with radiating veins. Dwarf-bushy types sprawl through beds and containers while climbing types scramble up a trellis. Every part except the roots - leaves, buds, flowers, pods, and seeds - is edible with a peppery, watercress-like bite, and the flowers draw hummingbirds and butterflies.

A tough, medium-sized native tree of the eastern and midwestern United States, grown as much for its showy edible orange fruit as for its distinctive thick, dark gray bark broken into rectangular blocks. Small urn-shaped white-to-greenish-yellow flowers open in May and June, and the sweet fruit ripens after frost. Largely dioecious - a female tree needs a male pollinizer nearby to set fruit - and notably drought- and walnut-tolerant once established.

Amur maple (Acer ginnala, accepted by Kew's Plants of the World Online as Acer tataricum subsp. ginnala) is a small, fast-growing deciduous tree or large multi-stemmed shrub from northeastern Asia - the Russian Far East, northeastern China, and Korea. At 15 to 20 feet it fits where a full-size maple cannot, and it earns that place with three seasons of interest: fragrant greenish-yellow flowers in spring, which is an unusual scent for a maple and an early nectar source for bees; small glossy three-lobed leaves through summer; and reliable, often brilliant red-to-orange fall color that arrives early. It is also one of the hardiest maples, tolerant of cold, wind, dry soil, and a wide range of pH. The honest catch, and it is a serious one for North American gardeners, is that it self-sows prolifically and has escaped cultivation to become invasive across parts of the US Midwest and Northeast, where its shade-tolerant seedlings crowd native shrubs and understory trees in open woods, savannas, and prairies. Several states list it as invasive or a noxious weed. Check your local invasive-species list before planting, and be prepared to remove seedlings if you do.

The domesticated orchard apple - a deciduous Rosaceae tree grown for its showy, edible fruit and fragrant April blossom of five white-to-pink petals around a ring of yellow stamens. Not native to North America (the genus Malus spans Europe, Asia, and North America, but the cultivated apple is an Old World hybrid lineage). Almost all varieties are self-incompatible: a second, different apple cultivar blooming at the same time must be nearby for fruit to set, and trees are grown on dwarf, semi-dwarf, or standard rootstocks that decide final size.