In Petri plate bioassays, we determined the allelopathic herbicidal effects of leaf and stem extracts (5, 10, 15 %) of Acacia nilotica L., Albizia lebbeck L., Dalbergia sissoo L., Mangifera indica L., Melia azedarach L. and Ziziphus mauritiana L. on seeds germination and seedlings growth of Avena fatua L. and wheat (Triticum aestivum L.). At higher concentrations (10 % and 15 %) of trees leaf water extract, increased wheat germination but decreased that of wild oats. The lower concentrations of M. mangifera, M. azedarach and D. sisso leaves stimulated the radicle length. All concentrations of M. azedarach extracts stimulated the radicle length of wheat. However, leaf and stem extracts of all Donor trees increased the plumule length of wheat.