Acer ginnala (Amur maple) and A. platanoides (Norway) are trees that perform well under challenging urban and suburban conditions. Unfortunately, both are highly fecund and have escaped cultivation in several regions of the United States including becoming invasive. To address this, we have developed seedless triploids. To safely deploy seedless cultivars that present little or no ecological risk, they need to be on their own roots, as opposed to being budded onto seedling rootstocks, as was customary for Norway maple. Growing own-rooted plants prevents possible outgrowth of seedling rootstock. Amur maple roots well from stem cuttings but this is not feasible for Norway maple. Micropropagation presents a path forward both to increase propagules rapidly for initial introduction as well as a viable propagation method for the more recalcitrant Norway maple. Both species were successfully micropropagated and stage III plants were delivered in early April 2023. Plants were acclimatized and grown during the 2023 growing season to produce finished trade gallon whips. Material was variable in size because we effectively grew on everything without culling for inferior material. Both species were demonstrated to be amenable to micropropagation and their growth after acclimatization was better than expected. Micropagation will be further optimized, and as available material increases, size and production will be further standardized. This method will facilitate rapid introduction of seedless triploids and allow growers to be successful and profitable in production.
