Au nanoparticles are commonly used as seeds for epitaxial growth of III–V semiconductor nanowires. However, the interaction between Au and In-containing III–V materials makes it difficult to control the growth of more complex nanowire structures in materials such as InAs. Here we report the growth of InAs nanowires and branched nanotrees using Au and Au–In nanoparticles. We show that the initial composition of the particle does not affect the morphology of the first-generation nanowires, nor does it affect the final composition of the particle after growth. However, when the Au–In particles were used to seed a second generation of nanowires, producing nanotrees, the branches exhibited a 2–3 times higher growth rate and more regular shape than those seeded by pure Au particles. This result is attributed to the decreased interaction between the seed particle and the trunk nanowires when Au–In particles are used. Thus the incorporation of In into the seed particle during particle production allows for modification of the particle–wire interaction.