Top wedge graft, splice graft, and chip budding were used in spring and in summer for propagation of Norway maple and its cultivars ‘Drummondii’ and ‘Faassen’s Black’. Graft union formation and the factors that affect it significantly were evaluated. It was proved that all three methods provide high success rate in spring (from 63.3 ± 11.6 to 93.3 ± 1.6 %), and that in summer, chip budding is preferable to grafting. After grafting the cultivars more (from 2.20 ± 0.37 to 3.37 ± 0.14 cm) but shorter shoots (from 171.8 ± 35.5 to 501.9 ± 29.3 cm) were formed in comparison with chip budding. Most intensive growth was observed after chip budding (from 290.0 ± 29.3 to 642.8 ± 42.8 cm) but the grafted scions started sprouting and growing earlier than the budded ones. The most significant factor for both graft union formation success and growth was the season of grafting/budding.