The 2012 ASHS Annual Conference

Winged euonymus [Euonymus alatus (Thunb.)] is an important landscape shrub that has a demonstrated potential to be invasive in numerous states across the central and northern United States. Nine cultivars were evaluated for their potential to produce fruits and seeds in a randomized, replicated field planting. Seed from ‘Compactus’ was evaluated in five natural environments (full sun meadow, edge of woods, moist woods, dry woods, pine woods) to determine which types of environments would support germination and establishment of winged euonymus cultivars. Seeds from all cultivars were evaluated for their ability to germinate and survive as seedlings in a deciduous woodland. Seed production for medium to large plants of cultivars varied from 981 to 6090 seeds per plant. The dry deciduous woods and pine woods environments were the only two that supported significant germination rates, which could be over 30%. Seedling survival was at least 77% in the deciduous dry woods and at least 55% in the pine woods. In the first time replication, establishment rates for cultivars in the dry deciduous woods ranged from a low of 6.5% for ‘Odom’ Little Moses™ to a high of 42.5% for ‘Monstrosus’. In the second time replication all cultivars achieved over 30% establishment and most exceeded a 40% establishment rate. By combining seed production data with establishment data, the annual seedling contribution per plant of different cultivars was predicted. Annual seedling contribution from individual landscape plants of different cultivars was predicted to range from 588 to 3763. None of the nine cultivars evaluated should be considered to be non-invasive based on our findings. Because germination and seedling survival rates are high for E. alatus, cultivars will likely have to be completely seed sterile to be considered non-invasive. Furthermore, E. alatus cultivars typically live multiple decades in the landscape and this must be considered when estimating their overall potential to contribute seedlings to natural environments.