There are 30+ varieties in the Quercus group, all producing acorns of differing sizes. Some stay on the tree for 2 years before dropping. Some are edible, with low levels of Tannin.
It is hardy to zone 4. It is in flower from Apr to May, and the seeds ripen from Sep to October. The flowers are pollinated by Wind. It is noted for attracting wildlife.
Succeeds in heavy clay soils and in wet soils so long as the ground is not water-logged for long periods. Dislikes dry or shallow soils but is otherwise drought tolerant once it is established. Tolerant of exposed sites though it dislikes salt-laden winds. The oak is a very important timber tree in Britain, it is also a very important food plant for the caterpillars of many species of butterfly, there are 284 insect species associated with this tree.