Rhizome assemblies and clump form and growth of nine arboretum grown bamboo species have been studied. Rhizome stalk has been found to play an important role in determining the form, shape and growth of clumps. This is due to not only the characteristic length of the stalk in some species but also its role in orienting the rhizome in relation to the centre of the clump and the mother culm in general and the line of gravity in particular. In areas where bamboos are worked heavily it is the rhizome stalk that is first affected and may result in congested clumps in species otherwise monopodial or loosely tufted. Rhizomes are commonly attacked by pathogenic soil ganisms, Parts like rhizome stalks, whole bud of the rhizome may be partly or wholly consumed or otherwise become inoperative and although these parts contribute to the development of rhizome assembly they do not contribute towards the growth of clump. This reduces the rate of growth of clumps considerably. Irrespective of species, only 8 percent of the buds develop into normal culms, 77 percent remaining dormant and 15 percent are damaged by pathogenic soil mlcrooganisms. It has been concluded tha- application of antipathogens individually or in combination with fertilizer will ameliorate the conditions of growth and considerably increase the outturn.