Teucrium — Germander
A member of the mint family (Lamiaceae, that also includes lavender and salvia), Teucrium is a fairly large genus of evergreen shrubs and subshrubs that includes species ranging from low perennial tufts to the nearly 8-ft. tall bush germander.
Teucrium is native to the Mediterranean area and therefore suited to Sonoma County gardens. All species are fairly drought tolerant and thrive in heat, in poor or rocky soils, and in other difficult situations. In rich garden loam, they may become lush and somewhat rangy. They take full sun to part shade, like well-drained soil, and are deer resistant. They can be left to develop a casual, natural shape or be sheared into formal topiaries or hedges.
The most common teucriums found throughout and well-suited to Sonoma County are Teucrium fruticans, T. chamaedrys (syn. T. x lucidrys) and T. cossonii majoricum.
Teucrium fruticans, bush germander, grows 6-8 ft. tall and wide, has small gray-green leaves with a silvery cast on a dense, twiggy shrub of downy-white stems. It blooms from January to July with tiny lavender-blue flowers at branch tips often buzzing with bees. Annual pruning is needed to ensure an attractive, tighter shape and prevent it from becoming too unkempt. Evergreen, bush germander is extremely durable even when subjected to wind and salt spray. It tolerates drought but requires occasional irrigation. A dwarf form, ‘Azureum,’ grows to 4-5 ft. but can be kept lower with pruning. ‘Compactum’ is even lower-growing.
Teucrium chamaedrys (syn. T. x lucidrys), wall germander, is a shorter, deep green, mounding form from 1 -2 ft. tall with spikes of pinkish purple flowers that rise above the foliage. Its leaves resemble soft miniature oak leaves—“chamaedrys” meaning "ground oak" refers to the leaf shape and ground cover habit. Thin, individual stems rise directly from the ground and slowly broaden the clump as it spreads by underground rhizomes.
This low germander looks most attractive when it forms a tight mound in full sun. In excess shade, stems tend to fall over and expose an open center. Periodic shearing helps maintain density but may sacrifice blooms. It can be pruned to a low hedge and is often used in classic intertwined knot gardens with Santolina.
Teucrium cossonii majoricum (syn. T. majoricum),called fruity germander for its foliage scent when crushed, is lower yet as it forms a loose tussock about 6 in. high spreading 1-3 ft. wide with small grayish green leaves on wiry stems. It may be used in masses as a non-invasive, slowly spreading groundcover for sunny sites where it attracts bees. Lavender-purple flowers cover the surface from spring into summer. After they fade to a rusty brown, flowers can be sheared for a re-bloom and mounds reduced by half to control shape. Only occasional irrigation is needed.
A true groundcover species, Teucrium chamaedrys ‘Nanum’ (syn. ‘Prostratum’ ) creeping germander, slowly spreads to 3 ft. or wider as it grows to about 6 in. high with small pinkish purple blossoms in spring. This long-lived perennial can be mowed or sheared to keep it even lower. Shearing prevents flowering but produces a walk-on carpet.
Teucrium scorodonia 'Crispum' is another groundcover, but is one to avoid. Attractive soft green leaves with ruffled margins are luring, but underground stems spread rampantly to the point of invasiveness and are extremely difficult to eradicate.