From little acorns
It’s not just oak trees that are impressive – their leaves are too, writes David Overend.
Autumn can spring a few surprises and pose plenty of questions – such as why are the leaves of some oak trees so much larger than the leaves of others? Line the fallen foliage side by side and the difference can be incredible.
Southern red oaks, also sometimes called Spanish oaks, have leaves which can be anything up to 12in in length, but the oaks found normally in the UK are more likely to be our smaller-leaved native oak, Quercus robur.
Quercus robur isn’t a garden tree; it’s a slow-growing potential giant. It demands space; it also demands time to grow and spread its huge canopy, developing a home for hundreds of different insects and encouraging birds to take up residence.
Quercus robur, the pedunculate oak, is a tree to be appreciated; like a good wine or a fine view, it demands more than just a quick glance.
But it’s not the only variety of oak to be living happily in Britain. Q petraea, the sessile oak, is also here in numbers, and it’s difficult to tell which is which – unless you know the tell-tale signs.
The acorns of the English oak have stalks, but the leaves do not; the acorns of the sessile oak do not have stalks, but the leaves do.
There are a few other forms of oak that can be found in this country. They aren’t here in great numbers, but they include Quercus rubra, the red oak from North America; Q cerris, the Turkey oak, which likes alkaline soil; Q alba, the white oak and yet another American import; and Q coccinea, which is renowned for its autumn colour.
Other oaks seen on these shores include Q palustris, the Spanish oak, and Q frainetto, the Italian or Hungarian oak, whose leaves are dark green above but pale and woolly underneath.
But back to those giant leaves...
They could well be the result of a tree or trees growing in shade – the leaves grow bigger in order to make use of every bit of filtered sunlight that they can.
And heavily-pruned oaks are encouraged to produce plenty of fresh foliage, sometimes far larger than normal.
The acorns of the English oak, Quercus robur, have stalks, but the leaves do not.