Several Imperata control options (shading, intercropping, chemical control) in smallholder rubber (Hevea spp) production systems were compared using a bioeconomic model. Imperata control was found to be highly profitable in most circumstances. Control early in the life of the rubber plantation was found to be critical both from biological and economic perspsctives. Rubber growing by Indonesian smallholders on Imperata grassland appears to be only marginally profitable under low intensity management. However, profitability was enhanced by management aimed at reducing the competitive effect of Imperata on the rubber. Cost-effective options include intercropping and chemical control, and enhanced shading with faster-growing rubber. The impacts of Imperata on rubber growth, and thus the economic benefits derived from controlling Imperata, are highest in the first year following planting. Economic benefits decline in subsequent years, but remain significant up to approximately the fifth year.