Central Canadian Shield forests

A tall, bold warm-season annual from Mexico and Guatemala (the "African" name is a misnomer of its European garden history) grown for large, fully double, pompon-like flowerheads in saturated yellow, gold, and orange over strongly aromatic, finely divided foliage. Plants reach 1 to 4 feet and bloom from early summer to frost in full sun. The petals are edible and used as a culinary garnish and natural dye, and the flowers are the iconic "flor de muerto" of Mexican Day of the Dead. Despite the wide listed zone range it is frost-tender and grown for a single warm season.

A dense, conical-to-narrow-pyramidal evergreen tree native to eastern and central North America, prized as a screening and foundation conifer. Flat, fan-like sprays of scale-like, aromatic yellow-green foliage clothe the tree from the ground up, and red-brown bark exfoliates on mature trunks. Wild trees can reach 40 to 60 feet but cultivated plants typically stay near 20 to 30 feet; small urn-shaped cones and dense evergreen cover make it valuable food and shelter for birds.

A medium-to-large native shade tree of central and eastern North America, reaching 50 to 80 feet with an ovate-rounded crown and large, asymmetric heart-shaped leaves. In June it carries pale-yellow, intensely fragrant flowers on pendulous cymes - each cluster hung from a distinctive strap-like leafy bract - that ripen into pea-sized nutlets. The fragrant June bloom is a premier nectar source: Missouri Botanical Garden lists it as attracting bees and butterflies, and the Lady Bird Johnson Wildflower Center flags it as having special value to both native and honey bees.

A native eastern + central North American multi-stemmed deciduous shrub with dentate (toothed) foliage, white spring flower clusters, blue-black drupes, and reliable fall color. Especially valued for wildlife - among the most-cited native shrubs for fall-migration bird forage.

A fast cool-season annual of the mustard family grown for its peppery, mustard-like salad greens - irregular, pinnately-lobed basal leaves in a low rosette, each with 4 to 10 small lateral lobes and a large terminal lobe (Missouri Botanical Garden). First cultivated by the ancient Greeks and Romans and still widely grown across Europe, it is best grown in the cooler spring and fall months rather than summer heat; leaves are harvested young and tender before they turn strong and bitter. Pale-yellow four-petalled flowers with dark brown or purple veins appear in corymbs if plants are left to bloom.

A cool-season Asian leaf vegetable grown for its loose, non-heading rosette of dark-green leaves carried on broad, juicy white stalks - the spoon-shaped petioles that distinguish it from heading cabbages. Missouri Botanical Garden PlantFinder records that the group spans varieties from 3 to 4 inches to 24 inches tall and is edible at every stage, from seedlings to small immature heads to large mature heads and even while flowering. The stems are mild and juicy while the leaves carry a cabbage-like flavor; like other brassicas it tolerates light frosts but bolts in summer heat.

A rough, sprawling Mediterranean annual grown for showy, open racemes of drooping, star-shaped bright blue flowers in summer. Branched stems and wrinkled, dull gray-green leaves are clad in bristly hairs and carry the taste and fragrance of cucumber. Easy in poor, dry soils, drought-tolerant, a magnet for bees, and a self-seeder that returns to the garden year after year.

Boxelder (Acer negundo) is the maple that does not look like a maple. Instead of a single lobed leaf it carries compound leaves of three to five toothed leaflets, close enough to poison ivy that people regularly misidentify young shoots, and it is one of the very few dioecious maples - male and female flowers on separate trees, so only the females carry the familiar paired samaras. It is native across an extraordinary sweep of North America, from Maine to Manitoba and south to Florida, Texas and central Mexico, and it is genuinely at home on riverbanks and floodplains where its speed and flood tolerance are assets. In a garden it is usually a volunteer rather than a choice. It grows fast, breaks in storms, seeds everywhere, and hosts the boxelder bug, which overwinters on house walls in numbers that make it a household nuisance rather than a garden one. The case for it is narrow but real: it establishes on ground where better trees fail, in cold northern climates and on raw disturbed sites, and it is a documented larval host for cecropia and a valued early honey-bee forage.

A cool-season vegetable grown for its large, tight, terminal head of green flower buds on a thick edible stem, framed by waxy blue-green leaves. Grown as an annual; it grows poorly once daytime temperatures consistently exceed 80°F, so it is timed for spring and fall. Harvest promptly while the head is firm and tight, before the buds begin to open.

A slow-growing, long-season cool-weather vegetable grown for the miniature cabbage-like buds (1 to 2 inches wide) that form in the leaf axils along a single 2-3 foot stem. It is the same species as kale, cabbage, broccoli, cauliflower, and kohlrabi, differing only by cultivar group. Flavor improves after the first fall frost, so it is timed for a cool-temperature autumn harvest rather than summer heat.

A cool-weather leaf vegetable grown for its dense, edible head of tightly wrapped blue-green, red, or wrinkled (Savoy) leaves. A biennial almost always grown as an annual, it forms a 3-4 pound head in about 80 days and rarely flowers in cultivation. It shares its species with kale, Brussels sprouts, broccoli, cauliflower, and kohlrabi, and grows poorly once daytime temperatures stay above 80°F.

An Old World cottage-garden annual grown for daisy- to chrysanthemum-like flowerheads (3 to 4 inches across) in bright yellow through deep orange, often with a contrasting darker center disk. In cool climates it blooms over a long summer-to-fall window; in hot summers it tends to languish and may need a midseason cutback to rebloom. The somewhat bitter flowers and lance-shaped aromatic leaves are edible, and the petals lend color to soups, rice, and baked goods.

A native eastern + central North American thicket-forming shrub producing arching thorny canes + clusters of large sweet black berries in mid-to-late summer. Among the most important wildlife fruit producers in eastern forests - birds, mammals, + insects all depend on the fruit. Like raspberry, biennial-caned (primocane year 1, fruits in year 2 as floricane, then dies back). Spreads via root suckers + tip-rooting cane tips; manage with annual pruning.

A fast, suckering native shrub of streambanks and moist thickets across eastern North America, grown for huge flat-topped cymes of tiny lemon-scented white flowers in early summer and the clusters of dark elderberry drupes that follow. Spreads by root suckers into naturalized colonies 5 to 12 feet tall and wide; the flowers feed butterflies and the showy fruit feeds birds. The raw berries are not eaten fresh - they are cooked into jelly, pie, and wine.

The American elm is the great vase-shaped shade tree that once arched over Main Streets and town commons across eastern North America - a fast, extremely cold-hardy deciduous tree of 60 to 80 feet whose upright trunk divides into a fountain of high, spreading limbs that meet overhead to form a living cathedral ceiling. That iconic form, and the species' tolerance of wet soil and tough urban conditions, made it the default American street tree for a century. Then Dutch elm disease (DED) - an introduced fungal disease carried by elm bark beetles - swept through in the 20th century and killed the vast majority of mature street and shade elms across the continent. The honest reality for a gardener today is blunt: do not plant the unselected wild species expecting it to survive. If you want the American-elm form, plant a DED-tolerant cultivar bred and selected for resistance - 'Princeton', 'Valley Forge', 'New Harmony', or 'Jefferson' - and say so plainly. Where it does grow, it is fast, hardy to USDA zone 3, and remarkably forgiving of wet ground and city stress.

A small-to-medium understory tree of dry, rocky eastern-North-American woods, named for its drooping clusters of papery, sac-like seed pods that resemble the fruit of hops. The birch-like, sharply-serrated leaves turn an undistinguished yellow in fall, and reddish-brown male catkins persist on the bare branches through winter. Also called ironwood for its extremely hard, dense wood; tough, low-maintenance, and drought-tolerant once established.

A small native deciduous tree (or thicket-forming, suckering shrub) of eastern and central North America, grown for clouds of fragrant white 5-petaled flowers that open in March before the leaves and for the edible red plums that follow in early summer. It forms a broad, spreading crown with attractive dark reddish-brown twigs that sometimes carry thorny lateral branchlets. A documented larval host for swallowtails and other butterflies, with flowers of special value to native, bumble, and honey bees.

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.

A native eastern-US deciduous shrub - 'Annabelle' is a sterile-flowered cultivar of smooth hydrangea - with very large white snowball blooms in summer. Blooms on new wood so spring frost cannot destroy the flower display, and serves as the larval host for the hydrangea sphinx moth.

A native central + eastern US perennial with intensely aromatic foliage when crushed and dense clouds of small blue-purple flowers in late fall - often the latest-blooming aster in the eastern flora. Drought + clay tolerant; among the toughest native fall pollinator plants.

A long-lived herbaceous perennial vegetable grown for the tender young spears harvested in April and May before they unfurl. Native to Europe and temperate Asia, it grows from a crown that takes 2-3 years to come into production but then yields for fifteen years or more. Spears left uncut grow into airy 3-4 foot summer ferns; the plants are dioecious, and female plants ripen ornamental red berries in late summer.

A clump-forming herbaceous perennial grown for its showy late-season flower heads: masses of tiny star-like flowers borne in flattened cymes 3 to 6 inches across that emerge rosy pink, deepen to rose-red, and fade to coppery-rust as they die. Gray-green, fleshy, succulent-like leaves form upright clumps to about 24 inches. Easily grown in dry-to-medium, well-drained soil in full sun, it is drought tolerant and attracts butterflies, and its foliage and dead inflorescences persist into winter for added interest.

Balloon flower is a long-lived East Asian perennial grown for its inflated, balloon-like buds that pop open into wide, five-petalled violet-blue (or white or pink) stars in mid- to late summer - one of the most distinctive bloom shapes in the border. Native to China, Korea, Japan, and the Russian Far East, it is bone-hardy (USDA zones 3a-9b) and largely trouble-free once established. The honest catch is its very late spring emergence: balloon flower is among the last perennials to surface, reappearing in late spring when other beds are already full, and its fleshy tap-like roots resent disturbance - mark it clearly, never move it, and resist the urge to poke around the crown before the shoots appear.

Balsam fir (Abies balsamea) is THE Christmas tree of the northeast and, for most gardens, a tree to admire rather than plant. Missouri Botanical Garden is unambiguous about why: the species is native to cool climates and is not recommended for planting in the hot and humid summer conditions south of USDA Zone 5, it is generally intolerant of urban pollution, and MBG explicitly does not recommend it for its own St. Louis climate. Wikipedia puts the same limit the other way round - it wants a mean annual temperature near 40°F with consistent moisture, and low moisture combined with high temperature is what stops the range. This is a boreal tree. It runs from Labrador and Newfoundland west to Alberta and south to Minnesota, Wisconsin, New England and New York, then survives in the Appalachians only by climbing, hanging on at 2,500 to 5,000 feet as far south as Virginia and West Virginia. Where it does suit the climate it is superb: a narrow aromatic spire of 50 to 70 feet and only 15 to 25 feet wide, clothed in flat blunt needles 0.6 to 1.2 inches long, dark green above with two chalk-white stomatal bands beneath and twisted at the base so they lie in two horizontal ranks either side of the shoot. Two features are worth learning by hand. The young bark is smooth and grey and studded with RESIN BLISTERS that spray when punctured - no spruce or pine does that - and the erect cones, 2 to 3 inches and dark purple, ripen brown and DISINTEGRATE on the branch in September, dropping their scales and leaving a bare central spike standing on the twig. A fir cone is therefore something you almost never find whole on the ground, which is the single fastest way to tell Abies from Picea. That resin is also the reason this tree has a place in the history of optics: Canada balsam, the oleoresin tapped from those bark blisters, dries to a transparent mass with a refractive index near 1.52, effectively the same as crown glass, so it worked as an invisible glue for cementing lens elements and became the standard mounting medium for microscope slides from about 1830. It was phased out during the Second World War for polyester, epoxy and urethane adhesives, which do not yellow and have far better thermal and solvent resistance. The honest catch list is long: balsam woolly adelgid, spruce budworm (this is the budworm's preferred main host), bark beetles, spider mites in hot spells, cankers, heart rot, root rot, needle rust and twig blight, plus heavy deer browsing, shallow roots that make it wind-firm only in a stand, and a working life measured in decades rather than centuries.