The common indoor/outdoor plant most people know as geranium is, botanically, Pelargonium. Considered here are true geraniums, which are mostly hardy plants. Many types bloom over a long period, bearing flowers that are attractive though not always as showy as those of pelargoniums. Carried singly or in few-flowered clusters, blossoms have five overlapping petals that look alike. (Pelargonium flowers also have five petals, but two point in one direction, while the other three point in the opposite direction.) Colors include blue, purple, magenta, and bluish rose; some are pure pink or white. Beak-like fruit that follows the flowers accounts for the common name “cranesbill.” Leaves are roundish or kidney shaped, lobed or deeply cut; plants may be upright or trailing.
Good in rock gardens, perennial borders; some are useful as small- or large-scale ground covers. A few shrubby species are good for holding slopes. Best climates for most geraniums are cool- and mild-summer regions, where plants can grow in full sun or light shade. In hot-summer areas, give afternoon shade. South African species are less cold hardy but more tolerant of heat, afternoon sun. All species appreciate moist,well-drained soil.
Some geraniums benefit from being cut back after flowering or in the fall; these are noted in text. Clumps of most types can be left in place for many years before they decline due to crowding; at that point, divide in early spring. Increase by transplanting rooted portions from a clump’s edge; or take cuttings. Many produce lots of seedlings, and some can become naturalized pests.Geranium cinereum
From the Pyrenees. Forms wide, 8–12-in.-tall mats composed of 1–1 1/2-in., soft gray green leaves that are rounded, bluntly lobed, and deeply cut. In early to midsummer, slender, trailing stems bear many cupped, 1–1 1/2-in.-wide flowers in pale pink with dark veinsGeranium himalayense
Himalayan native to 1 1/2 ft. high, spreading by rhizomes. Long-stalked,medium green, 2 1/2 -in.-wide leaves are roundish, with prominent veins and five broad, deeply divided lobes. Blooms from late spring into summer; 1-ft. stems bear clusters of 1 1/2 –2-in.-wide blue flowers with reddish veins and purple eye. Excellent deciduous small-scale bulb cover; plant 1–1 1/2 ft. apart.Geranium incanum
From South Africa. To 6–10 in. high, spreading fast to form a 2-ft.-wide cushion of finely cut leaves. Inch-wide light magenta flowers appear from spring to fall. Cut to ground every 2 or 3 years in late fall to keep plants neat.
Endures heat and drought better than most geraniums, but needs some summer water. Self-seeds profusely and can be invasive.Geranium macrorrhizum
From southern Europe. To 8–10 in. high, spreading fast by underground rootstocks and fleshy rhizomes that root on soil surface. Thick, hairy, sticky, five- to seven-lobed leaves are 3–4 in. across; foliage has a strong,musky fragrance and attractive autumn coloring ranging from dull yellow to orange and scarlet. Inch-wide flowers in white, pink, or magenta. Blooms late spring through early summer; some repeat in fall. Good ground cover for small areas, though it can overwhelm smaller plants. Succeeds in dry shade.
Dramatic native of Madeira likes moist conditions, shade. Largest of all geraniumleaves (to 2 ft. long)—overlapping,glossy, deeply divided,shaped like giant snowflakes. Reddish brown leafstalks helpbuttress the 3–4-ft. “trunk” supporting hundreds of densely packed, fuzzy buds and magenta-eyed deep pink blossoms to 1 1/2 in. wide. Blooms early spring through midsummer. Biennial or short-lived perennial; dies after blooming but spawns many seedlings.Geranium phaeum
Shade-loving native of southern and central European mountains. To 2 ft. high,1 1/2 ft. wide. Leaves are basal, 3–4 in. across, shallowly cut into seven to nine tooth-edged lobes, often with brown markings. Clusters of dusky purple or maroon blossoms rise above foliage mass from spring to fall. Cut back flowering stems after bloom to neaten appearance and encourage rebloom. Excellent with ferns in a woodland garden.
Native from Ireland to Siberia and Japan. Forms a clump 1 1/2–2 ft. tall, 2– 3 ft. wide. Hairy, 3–6-in. leaves on upright stalks are deeply cut into seven narrow, pointed, divided lobes. Flowers are about 1 in. wide, typically blue with reddish veins; bloom from spring through summer. Self-seeds profusely; cut to ground when flowers fade to prevent seedlings and encourage rebloom.
From the Caucasus. Compact grower to 1 ft. high and wide. Velvety gray-green leaves have deeply etched veins and scalloped lobes. Early to midsummer flowers are white with violet veining; overall effect is pearly gray. May be cut back hard in fall.Geranium sanguineum
Native from western Europe to the Caucasus and Turkey. Forms dense clump 8– 18 in. high, spreading by rhizomes to 2 1/2 ft. or wider. Dark green, 1–2-in.-wide leaves are deeply divided into five to seven lobes, each with three narrow segments; turn blood red in fall. Typical forms have deep purple to almost crimson flowers 1 1/2 in. wide; bloom late spring well into summer and will rebloom if cut to ground.Geranium sanguineum striatum
Compact subspecies, only 5–6 in. high. Bears light pink flowers heavily veined with red (its seedlings may vary somewhat) and makes an excellent rock garden or foreground plant.Geranium subcaulescens
Native to the Balkans, Turkey. Like G. cinereum (8–12-in.tall, spreading mat of leaves), but with darker green leaves and brilliant crimson magenta flowers with black centers and veins.Geranium x cantabrigiense
Excellent ground cover, 6– 8 in. high, spreading slowly but widely. Pleasantly scented, dark green leaves are 1 1/2 –2 1/2 in. wide and deeply cut with multiple lobes. Long-lasting flowers are about 1 in. across. Plants may be sheared in late fall for fresh spring growth.Geranium x oxonianum
This hybrid species includes dozens of varieties of free-flowering, mounding, spreading plants. Blooms of most varieties are in the pink range, from nearly white to deep mauve, some with delicately marked petals. Tends to reseed and can overwhelm smaller neighboring plants. Good ground cover among shrubs.'Ann Folkard'
Mounding, billowing plant (1 1/2 ft. high, to 5 ft.wide) with chartreuse leaves that age to light green. Saucer-shaped, 1 1/2-in.-wide blossoms are rich magenta purple suffused with pink and blue, centered and veined in black. Blooms from spring into fall. Effective planted at edge of patio and sprawling onto it.'Brookside'
Hybrid developed by crossing G. pratense and a purple form of G. clarkei. To 2 1/2 ft. tall and as wide, with deeply serrated, 3-in.-wide leaves. Plant is covered from late spring into summer with bowl-shaped flowers to 2 in. across. Long-lasting blooms are rich, deep blue with pale centers and pink veins. Its seedling ‘Orion’ is similar, but with larger flowers of an even richer blue. Both can be cut back after flowering for repeat bloom.'Johnson's Blue'
Popular hybrid resembling its G. himalayense parent, but leaf divisions are narrower. Mounds 1 1/2 –2 ft. tall and spreads by rhizomes to 2–3 ft. Excellent summer ground cover. Abundant 2-in., blue-violet flowers in loose clusters from spring to fall. Blossoms are sterile.
Much of material sold under this name is ‘Gravetye’ or another G. himalayense form, with a shorter bloom season and fertile flowers.'Pink Spice'
Compact mound 8–10 in. tall, to 1 ft. wide. Reddish bronze, 1 1/2-in. leaves form a dark background for inch-wide pink blossoms on long, trailing stems. Blooms from late spring through fall. Foliage color is best with at least half-day direct sun. Ideal for a rock garden or spilling from a container.
This naturally occurring hybrid between G. himalayense and G. wallichianum ‘Buxton‘s Variety‘ is very popular and easy to grow. It is heat tolerant and blooms best in a sunny spot. Plants reach 1 1/2–2 ft. tall and spread a little wider, forming a lush mound of deeply lobed, 2-in.- wide medium green leaves with attractive chartreuse mottling; foliage takes on red tones in fall. Stunning flowers, to 2 1/2 in. wide, are rich violet blue with a large white eye.
Reaches 3 in. tall, 1 1/2 ft. wide, with cylindrical leaves and a summer-long display of rich purple f...
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Both species described here (one of which bears edible fruit) are Chinese natives with large, prominen...