There are two versions of the Washington navel orange tree, one of which is a dwarf variety, while the other grows as a full-sized tree. The dwarf variety of the Washington navel orange tree goes by the botanical name Citrus sinensis 'Dwarf Washington Navel,' and grows to be about 6 to 10 feet tall. The non-dwarf variety is called Citrus sinensis 'Washington' and can reach about 25 feet tall when it receives the proper care and growing conditions.