GARDENING: Bring a king into your garden

Often called the king of the wood, the oak does indeed support the greatest amount of wildlife of any plant while alive and also while dead – an estimated 2,300 species. There are two species of oak native to Ireland the pedunculate and sessile oak, the latter being more common.
Oak is will grow on poor soil and has great drought resistant, so is a good option for elevated areas. Its deep taproot can obtain water from deep ground water and also makes it difficult to topple in storms. Oak is too slow to bother consideration I hear. It certainly is slow to get to its maximum girth (about 300 years), but its vertical grow is quite rapid, and I have found it to be above two metres in height in only four years.
Oak acorns feed jay birds, wood pigeons, field mice and badgers. Oak foliage feeds about 1,100 insect species and their deep fissured bark is habitat for all kinds of creatures. The dead standing tree also hosts native honey bee hives and owls. Like birch, oak stimulates fungal proliferation in the soil around its root system – which greatly benefits soil fertility and water holding ability.


LIFE SUSTAINERS Dead standing oaks are teeming with life inside and out. Pic: Oliver Whyte Jnr

There are no better oaks than the local species that have evolved for our climate and soil over ten thousand years. The ‘most local’ heritage oak tend to be more successful and are ecologically more beneficial than mass-produced imported commercial stock that may even harbour disease – oak promissory moth being one example of an imported threat to our oaks. There are small pockets of ancient woodland that have by some miracle avoided the axe (and in more times the health, safety and insurance industry) and this is where to find our heritage oaks and their acorns to grow your own.
Growing your own oaks from acorn is very easy and rewarding. Some years no acorns are produced but in an abundant ‘mast’ year, thousands are produced by each tree. It is assumed this is a strategy to reduce the populations of acorn-eating creatures to increase the long term changes of mast year acorn germination and seedling survival. I have read in literature it takes 80 years for oaks to produce acorns – the oaks we have grown started to produce acorns from ten years of age.
Once acorns are harvested in early October (after a good wind) plant them near the surface of a deep container and their taproot will immediately start to descend over the winter. Acorns are a very nutritious food for many creatures so protect your modest collection and other tree seeds from mice and birds with a fine mesh (about 6mm) which can be removed later in the year. Make sure the soil does not dry out or become water logged.
A rua/rust coloured shoot will emerge the next May. When the seedling is getting bigger, pot on to a larger container or plant into its permanent location. I usually wait until the sapling is about 50cm in height so that grass competition is no longer an issue. The hardier sessile oak will grow in any soil type, grows in full or partial shade, and is low maintenance.
Oaks can grow up to 38 metres in height, and as such an untrained oak would not be a wise option in a small garden. It would be a great centre piece in a medium- or large-sized space though. Single trees or dense concentrations of hedging are both well established methods of oak growth in gardens. Beech hedging seems a popular choice due to the attractive and occlusive winter leaf foliage. Interestingly, oak and beech have quite similar characteristics – both are apex canopy trees that hold onto their deciduous leaves during the winter. Maybe we could switch our preference to oak hedging instead, which would be much more beneficial to our local ecosystem.

Oliver Whyte’s garden, Coill an Chúir at Sandyhill, Westport, is included on the Clew Bay Garden Trail. A chain of beautiful and unique private gardens, the trail opens to the public during summer to raise funds for charity (see www.clewbaygardentrail.ie for more). Each month, an article by a trail member appears in these pages.