Acer Duo The Acer Duo combines two attractive acer varieties that will create beautiful focal points for sheltered parts of the garden. Their slow-growing habits make them perfect for growing in large containers on the patio or as free-standing specimens in borders. Height and spread: 4m (13’). Acer palmatum Duo comprises: Acer palmatum 'Atropurpureum'- A classic Japanese Maple producing gorgeous, purple-red foliage that colours to brilliant, fiery red in autumn. Acer 'Osakazuki Seedling' - This striking variety is well regarded for its intense autumn colours.