Thuja

These evergreen trees are found wild in North America, Korea, Japan and China. They are very pretty trees and are hardy in most parts of North America where the soil is suitable and atmospheric conditions are fairly clean. The leaves of this tree, also known as Arborvitae, Northern White Cedar, and Swamp Cedar, are scale-like and overlap each other tightly against the twig. They are yellowish-green, one-eighth to one-fourth of an inch long and ovate with a pointed or blunt tip. The branchlets spread out in fan-shaped sprays. The small cone is about �-inch long and matures during the first fall but remains on the tree throughout the winter. The bark of the trunks is thin and ashy to light reddish-brown. It is shed in long, narrow, shredded strips. When bruised, the branches of some kinds, notably T. plicata and T. occidentalis, give off a scent that resembles a mixture of Tansy and Turpentine. The wood of these trees is used for construction, cabinet work and cooperage. It is preferred when great durability is required to endure exposure to all kinds of weather. This wood is very resistant to decay. Some Thujas form good hedge plants and screens.

Pot Cultivation

Arborvitae thrive where the climate is fairly moist, on acidic sandy or peaty soil. They should be planted when they are small, though when they are properly balled and burlapped, trees 8 to 10 feet high may be planted without much danger of loss or serious harm. Planting should be done in mild weather in the spring or early fall. These trees don't grow well on lime soil, though they will flourish where a limestone subsoil is covered with a moderately deep layer of non-limy soil. When grown as ornamental trees, little pruning is required, but for the occasional removal of dead lower branches. When they are grown as hedges, they are sheared once or twice a year. Make sure not to cut back into wood more than a year old. There are many dwarf varieties of Thujas that are great for rock gardens and foundation plantings. The have slow and compact growth.

Propagation

Sow seeds in beds of light soil, in late spring on a calm day. They should only be covered very lightly. Seeds may also be sown in containers of light soil and placed in a greenhouse or frame early in February. The new trees should be transferred to a nursery bed in May or potted singly in small pots and buried to the rims in a cold frame. Hybrids may be increased by inserting cuttings of young shoots in a bed of sand or sand and peat moss in a warm greenhouse in the autumn. They can also be increased by grafting them to their respective types, which have been established in pots. They should be placed in a warm greenhouse.

VARIETIES

• T. occidentalis (American Arborvitae) & var. w/ golden leaves - aurea, Douglasii aurea, lutea, lutescens, semperaurea, Vervaeneana, Buchananii, compacta, conica, fastigata, filicoides, Riversii, robusta, Rosenthalii & viridis. Dwarf var. - Boothii, dumosa, globosa, Hoveyi, nana, pumila, pygmaea, recurva nana, umbraculifera, filiformis, Ohlendorfii, pendula, Ellwangeriana, ericoides.
• T. orientalis (Oriental Arborvitae) & var. aurea, semperaurescens, bonita, elegantissima, Hillieri, minima glauca, Rosedalis, flagelliformis, meldensis & stricta.
• T. plicata (Giant Arborvitae) & var. atrovirens, aurea or zebrina, fastigiata, Hillieri, pendula.
• T. Standishii (Japanese Arborvitae).
• T. koraiensis.