Description
Quercus – Oak –
There are about 600 long lived, monoecious, deciduous, semi evergreen or evergreen trees to 120′ feet tall and shrubs to 3′ feet tall, in this genus. They are widely distributed in woodlands and scrub in the Northern Hemisphere. They are grown for their habit and foliage. They have usually fissured bark, downy to hairless shoots, and alternate, smooth edged, lobed, or toothed leaves, which in some deciduous species produces excellent red or yellow-brown autumn color. The tiny male and female flowers are produced separately on the same plant from mid spring to early summer, the males are borne in pendent yellowish-green catkins, the insignificant females singly, in pairs, or in racemes, followed by ovoid brown nuts (acorns) in scaly cups. The acorns are mostly ½-1 1/4″ long, sometimes more, and solitary or paired, but in some species are borne in racemes. Oaks can be divided into ‘White Oaks’ and ‘Red Oaks’, White Oaks have rounded leaf lobes and edible acorns that mature in one year. Red Oaks have pointed leaf lobes and acorns mature in two years and are too bitter to eat. Oaks are best as specimens in a large garden or park. Timber has long been prized.
Grow in deep, fertile, well drained soil in sun or partial shade, evergreen species prefer full sun. They tolerate alkaline soils unless stated otherwise.
Prone to borers, caterpillars (including gypsy moth larvae), leaf miner (including oak leaf miners, skeletonizers, scale insects, leaf rollers, wilt, anthranose, twig blight, cankers, powdery mildew, orange hobnail, leaf blister (curl or gall), rust, mushroom root rot, white heart rot, aphids, oak root fungus, and a variety of leaf spots.
Q. acutissima – Q. serrata – Sawtooth Oak – Japanese Oak – Japanese Chestnut Oak -This slow growing, lime hating, rounded, deciduous tree from the Himalayas, China, Korea and Japan grows 50-80′ feet tall and wide. It has roughly ridged and fissured, corky, dark gray to black bark. It produces chestnut-like, oblong-lance-shaped to obovate, glossy, mid green leaves to 8″ long, edged with bristle-tipped teeth, which turn yellow in fall, and hold on into winter. It bears solitary, ovoid acorns held in cups covered with slender, long, hairy scales.
Zones 6-9
