“Juglans regia (Persian/English/Common Walnut) is a large, deciduous tree that makes a very good choice for parkland settings.
It can produce an abundance of nuts over a long period but not guaranteed in the unpredictable Irish climate.
The Juglans regia trunk is relatively short, has a smooth bark, and a broad, spreading crown. With substantial shade, the walnut also produces a substance in its proximity that can inhibit growth in other plants so is preferable as a standalone specimen.
Walnut trees grow best in rich loamy, deep soil with full sun and a southerly or westerly aspect.