Identification
Large tree with distinctive lobed leaves. Also, commonly appears in hedgerows. Acorns caps may have long (Q. robur) or short stem (Q. petraea).
Botany
The fruit, acorns, appear in mast years, occurring every 3-10 years. Oaks will grow for more than a thousand years, and support hundreds of other species; several are completely dependent on the oak. These include the purple hairstreak butterfly and some gall wasps.
Part of the plant to use
Galls, acorn caps, bark
Lore
The oak king is that of summer, sunlight and growth. The oak is a tree of rebirth and the renewed cycle of life – experiencing a second growth of leaves in late summer. It is said oak enables us to focus on time and memory. It helps us manifest goals, perhaps thanks to its own longevity.
Colour
Ochre: unmodified
Reddish brown: cooked in soda
Greys and blacks: + iron II sulphate
Reddish-orange: + baking soda
White “stars”: + citric acid
Making iron gall ink
A full recipe for making iron gall ink is also available.
Want to learn more?
We cover oak gall ink in-depth in session two of our botanical ink course, Galls to Nettles webinar series. The live sessions are over, but you can still buy the recordings (which come with comprehensive handouts, too). If you prefer print: Foraging for Colour includes an ink-making recipe for iron gall ink.