Perennial plants are herbaceous plants which die back to the ground during winter and grow back in spring. Some can be left undisturbed for years while others need to be divided every few years to maintain their vigour. You can find a perennial plant for any situation, whether it's a stone wall or a shady corner. Some are grown for their flower displays, others for their beautiful foliage. Evergreen perennials and half-shrubs are included in this category.
Ranunculus - Buttercups
Ranunculus is a large genus of around 600 species in the buttercup family, Ranunculaceae, with a global distribution. The latin name means little frog, which is a reference to their preferance to moist soil. Most flower in spring or early summer, usually yellow flowers, but a few flower white or greenish flowers. They prefer sunny positions.
Rhodiola - Stonecrops
Rhodiola is a genus in the family Crassulaceae, native to mountains and arctic regions in the northern hemisphere, the majority in China. One species is native to Iceland. (*)
Rodgersia is a small genus in the Saxifragaceae family, all native to E-Asia. They are grown in gardens for their large, bronze coloured leaves, but flower rarely in Iceland. They grow in shady places along streams in their native habitats, so they need moist soil and semi-shade.
Salvia - Sage
Salvia is the largest genus in the family Lamiaceae, with roughly 1000 species native to Eurasia and America. There are three distinct distribution areas, Central- and South-America, Central-Asia and the Mediterranean and E-Asia. Most species need a warmer climate than Iceland has to offer, but at least two species are hardy here.
Sanguisorba - Burnet
Sanguisorba, is a genus of about 30 species in the rose family, Rosaceae, distribitued around northern temperate regions. They are herbaceous plants or shrubs with clusters of small flowers. They grow best in moist soil and a sunny position.
Saponaria is a genus in the carnation family, Caryophyllaceae, native to Europe and Asia. The latin name means soapy sap, which refers to the saponin content of the sap, which foams like soap. At least Saponaria ocymoides has been used to make liquid soap by soaking the leaves in water. Most species have white or pink flowers. They grow in different conditions, some are good rock garden plants that need dry, sun baked soil, while others are taller and prefer moist soil.
Saxifraga - Rockfoils
Saxifraga is the largest genus of the Saxifragaceae family with roughly 440 species spread around temperate regions of the northern hemisphere. The latin name means stone breaking which could refer to many species growing in rock crevices at high altitudes. Other species are larger and grow on moist meadows, but most species, even those growing on cliffs, grow where there is some moisture. A few species are native to Iceland.(*)
Scutellaria - Scullcaps
Scutellaria, is a genus in the family Lamiaceae with a global distribution, mainly in temperate regions. Several species in this genus have been used in herbal medicine.
Sedum - Stonecrop
Sedum, is a large species of close to 600 species in the family Crassulaceae, with a wide distribution around the northern hemisphere. They are herbaceous or shrubby plants with thick, water storing leaves, very drought tolerant and thrive best in sun.
Semiaquilegia - False columbine
Semiaquilegia is a small genus in the buttercup family, Ranunculaceae, closely related to columbines (Aquilegia). The difference between them is that false columbines lack the spurs that columbine flowers have. Two species are grown as garden plants, both are native to China.
Silene - Catchflies
Silene is the largest genus of the carnation family, Caryophyllaceae, with a global distribution, the greatest number of species in the northern hemisphere. The prefert to be on the sunny side of life, many low growing species are excellent rock garden plants. One species is native to Iceland.(*)
Ornamental grasses belong to the grass family, Poaceae, along with f.ex. bamboo and grains, which with its 10.000 species is the fourth largest plant family. Grasses prefer full sun and tolerate dry, poor soils. All ornamental grasses are grouped together here instead of by their respective genera..
Soldanella - Snowbells
Soldanella, is a small genus in the primrose family, Primulaceae, native to mountain areas in Europe. They grow in moist meadows, woodlands and rocky mountainsides.
Stachys - Hedgenettles
Stachys is one of the largest genera in the Lamiaceae, family with 300-450 species most of which are native to temperate regions. The flowers are born in long flower spikes.
Symphyandra is a small genus in the bellflower family, Campanulaceae, closely related to bluebells (Campanula). Most are biennial and the majority are native to the Balkan peninsula and W-Asia.
Tanacetum, is a genus in the aster family, Asteraceae, with a wide distribution around the northern hemisphere. They have finely divided leaves and the flowers can be composed of both disc and ray florets (T. coccineum) or just disc florets (T. vulgare)
Thalictrum - Meadow-rues
Thalictrum, is a large genus of around 120-200 species in the buttercup family, Ranunculaceae, distributed around temperate regions. Their defining characteristics are finely divided leaves and flowers without petals, but with long colorful stamens in loose clusters. Some species have coloured sepals. They usually prefer moist soil and varying amounts of shade.
Thymus - Thyme
Thymus, is a genus in the mint family Lamiaceae, native to temperate regions in Europe, Asia and N-Africa. They are aromatic, evergreen herbs or subshrubs, some are grown as culinary herbs. One is native to Iceland.(*)
Thymus praecox ssp. arcticus*
Tradescantia - Spiderworts
Tradescantia is a genus in the family Commelinaceae native to the Americas from S-Canada to N-Argentina. A few are grown in gardens around the world, but they are probably a bit too tender for the Icelandic climate.
Trifolium - Clover
Trifolium is a large genus in the Fabaceae family, with a global distribution. They are nitrogen fixing and thrive in poor soils. They generally prefer full sun, but there are some species that tolerate semi-shade.
Trillium is a genus of 50 species in the family Melanthiaceae. This genus has been moved around quite a bit in recent years. It belonged to the lily family (Liliaceae) and when that family was divided, Trilliums were moved to the family Trilliaceae, which now has been combined with the Melanthiaceae family. They are woodland plants native to N-America and Asia and prefer part shade and fertile, moist, humus rich soil.
Trollius - Globeflowers
Trollius is a small genus of around 30 species in the buttercup family, Ranunculaceae, distributed around temperate regions in the northern hemisphere, the greatest number of species in Asia. They grow in moist soil in their native habitats, but can grow in any garden soils.
Verbascum - Mullein
Verbascum is a genus of around 360 species in the family Scrophulariaceae. Most species are native to SE-Europe and W-Asia. Most grow in sandy, gritty soil, but can grow in well drained garden soil. They need a sunny, sheltered place.
Veronica is the largest genus of the family Plantaginaceae, with roughly 500 species. The genus is currently in revision and a number of genera could be moved to the Veronica genus, among them the genus Hebe which is almost exclusive to New Zealand. Most species currently in the Veronica genus are native to northern temperate regions. They grow best in sun and any garden soil, although low growing species prefer well drained soil. A few species are native to Iceland. (*)
Vinca - Periwinkle
Vinca is a small genus in the family Apocynaceae native to Europe, NW-Africa and SE-Asia. They are herbaceous plants or subshrubs, ground covers, some very shade tolerant.
Viola - Violets
Viola is the largest genus in the violet family, Violaceae, distributed around northern temperate regions. There are a few species native to the southern hemisphere, in the Andes mountains and Australia. Most are low growing herbaceous plants, although a few are shrubby. A few species in the Andes have thick, water storing leaves. The most widely grown members of the genus are pansies and violets grown as annual flowers, but a few perennial species are grown in gardens. Five species are native to Iceland.
Waldsteinia - Barren strawberries
Waldsteinia is a small genus in the rose family, Rosaceae, native to the northern hemisphere. A few species are grown as shade tolerant ground covers in gardens.