Common Walnut Juglans regia
The Common Walnut tree can be identified by its pinnate leaves, catkins and fruit. It is native to a region stretching from south-east Europe to China, has been grown in Britain since Roman times. It is now common in gardens and parks especially in the South of England. The timber is highly valued for fine furniture and the nut has been used in cookery for more than 2000 years. Most walnut imports to the UK come from California, India and China.
A Common Walnut tree in September.
The pinnate leaf has 5 to 13, but usually 7, smooth-edged leaflets. The end leaflet can be huge. The leaves are bronze when they open in late spring and turn green in June.
Young trees have very pale grey, smooth bark.
Male and female flowers are separate but on the same tree (Monoecious). This photo shows a male catkin in May after a cold Spring. The tree is just coming into leaf.
Male catkins hang down like this in mid May, in a normal year. The catkin is covered from top to bottom in male flowers. Each flower has up to 20 deep purple anthers. This is a close-up of the deep purple anthers that release pollen onto the wind. Male catkins wither and drop off soon after releasing pollen.
Female flowers in early June after a late spring. The flowers are usually paired and are wind pollinated. They have no petals. Each flower has 2 styles extending from the top of its green ovary. The styles stick out to collect pollen released by the male catkins.
The ovaries become fruits like this in late June and will be ready to harvest in autumn.
This photo of a walnut, half eaten by a squirrel, shows the stony layer inside the fleshy layer with the seed missing. The Walnut fruit is a ‘drupe’ which is a botanical term for a fruit that has its seed enclosed by a stony layer.
Older trees have bark like this. The oldest trees have bark that is cracked into plates.