The Kindred Spirit® Hybrid Oak is an oak hybrid of Quercus robur 'Fastigiata' × Quercus bicolor thus forming a Quercus x warei. In layman's terms this means an Upright English Oak was hybridized with a Swamp White Oak and this tree was one of the progeny. Kindred Spirit® Hybrid Oak is the trade name of Quercus × warei 'Nadler'.