Allelopathy is the phenomenon in which one plant releases the chemicals which
could either stimulate or inhibit the growth of the others in the vicinity. This study
attempted to extract one of the allelochemicals from the flowers of the weed called Typha augustifolia and investigated the effect of the obtained extract on the growth of the other weed called Mimosa pigra. The main objective is to reduce the application of the chemicals used widely at present to eliminate the weeds since they could result in the residual accumulation in the environment. The flowers of Typha augustifolia were chemically extracted by the method of Markham, K.R. 1982. The obtained extract was then tested for identification using spectrophotometry to detect the maximal wavelengths and the chemical tests (Shinoda, 1928 and Pew, 1948). The obtained spectra revealed maximal wavelengths at 275 and 310 om respectively. Together with the results from chemical tests, the overall results indicated that the major component present in the extract appeared to be flavonone.The various concentrations of the extract were then later tested to study the effect on the growth of the Mimosa pigra. The results showed clear inhibition and that inhibitory effect was shown to be concentration dependent.