Eastern Arborvitae 'Smaragd'

White cedar 'Smaragd' (Thuja occidentalis 'Smaragd') is a slender green candle that keeps glowing even in December. Its glossy scale-like foliage is arranged in flat sprays, the crown holds a narrow dense cone all by itself, and the colour, unlike that of many arborvitaes, does not brown or grey off in winter.

That is why 'Smaragd' is the default plant for clipped and informal hedges, avenues and accents by a doorway. At ten years the tree is about 2 m tall and 50 cm wide and adds roughly 30 cm a year, so it stays narrower and calmer than the globe cultivars. Give it full sun: in deep shade the crown noticeably thins.

Key characteristics:

• What makes it special: The foliage does not brown in winter - the plant stays emerald through the hardest frosts, and it takes down to -45.6 °C.
• Dimensions: In 10 years it forms a slender cone 2 m tall and 0.5 m wide.
• Hardiness: Overwinters without cover and withstands frosts down to -45.6 °C (USDA zone 2).
• Light: Give it full sun: that is where the crown stays dense, while in deep shade it noticeably thins out.
• Soil: Takes readily to any garden soil - chalk, clay, loam or sand, any pH - as long as it stays moist and well-drained.
• Watering: Water moderately but regularly: the one thing this thuja will not forgive is the soil drying out.
• Care: No pruning needed; young plants do best in a sheltered spot away from dry, exposed winds.
• Landscape use: A classic for hedges and screens, architectural accents, patio containers, rockeries and cottage plantings.
• Origin: A seedling selected in 1950 at the Danish nursery D. T. Poulsen in Kvistgard; holder of the RHS Award of Garden Merit (2003).