T

Tanacetum
 

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. 

Thlaspi - Pennycress
 

Thlaspi is a genus in the family Brassicaceae, native to temperate regions of Eurasia. They are low growing rock garden plants with white or lilac flowers. 

 

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 sub-shrubs, some are grown as culinary herbs. One is native to Iceland.(*)

 

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 - Smárar
 

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
 

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.