Answer: There's really no way to tell without comparing the plants, or by reading the descriptions and choosing the one that best fits the plants you have. Here's what I know about nandina cultivars:
Compacta (Nana); 4 to 5 feet; Red winter foliage; white flowers; red berries.
Moon Bay; 1.5 to 2.5 feet; Bright red to reddish green winter color; leaves are smaller than the species with a slight cupping tendency; light green summer leaves; grows into a broad mound. Okame; Uniform bright red foliage color in early season; mounded, compact habit. Plum Passion; 4 to 5 feet by 3 to 4 feet; New growth is deep purplish red; deep green in summer; reddish purple in winter; narrow leaflets; moderate growth rate. Town and Country; 2 feet by 4 feet; foliage similar to the species; heavy berry set. Umpqua Princess; 3 to 5 feet, Typical foliage. Umpqua Warrior; 6 to 9 feet, typical foliage. 'Royal Princess'; an upright growing shrub to 6 to 8 feet tall has very lacy foliage. Pinkish white flowers bloom in clusters at the ends of branches in the late spring and summer followed by a heavy set of red berries ( notably heavier than most Nandina cultivars). The foliage turns to burgundy in spring and later a orange-red in fall. Branching stands stiffly upright unlike typical Nandina domestica and the foliage has a much finer texture.
Hope this helps you!
Q&A Library Searching Tips