Buds of ‘Valencia’ orange implanted in ‘Troyer Citrange’ rootstocks remain dormant for variable periods. A range of growth substances was applied either to the buds before implantation or through a wick following bud union with the stock in an attempt to promote rapid budburst. Soaking the buds in solutions before budding caused the death of some buds, particularly with gibberellic acid solutions. 6-benzylaminopurine promoted earlier budburst in most circumstances and may be helpful in nursery practice; other growth substances produced variable results.