Issai hardy kiwi

Actinidia arguta ‘Issai’

 Actinidia arguta ‘Issai’ exhibiting foliage yellowing at UW in Fall 2025.  Photo: A Keyser-Gibson, Actinidia arguta Kiwi Magic® 

Summary

Issai Hardy Kiwi

Actinidia arguta ‘Issai’ is a deciduous, woody vine grown for the edible fruit. This cultivar is self-fertile and produces the sweetest hardy kiwi fruits when compared to other cultivars. Foliage features ovate, toothed dark green leaves. Fruits are preceded by small, scented green-white flowers in June, with edible, smooth-skinned grape-sized fruits maturing in September-October. This cultivar prefers well-drained soil and full sun to part shade growing conditions. ‘Issai’ has a reduced growing habit when compared to other cultivars which decreases pruning needs. Once established, this vine features a fast rate of growth. This cultivar is reported to be well suited for USDA zones 3-8.

        Actinidia arguta ‘Issai’ was planted in summer of 2024 (year 2 of the trial) after complete mortality occurred for a previous taxon over the winter. Individuals of this taxon were irrigated at the 80% ET₀ treatment during the summer of 2024 and received one year of irrigation deficit treatment in 2025. However, plant establishment was slow and of the 24 individuals planted, mortality occurred in 8 over the 2024-2025 winter. Those that survived displayed very slow rates of growth across the deficit irrigation. This taxon is recommended on the medium irrigation (50% ET₀ treatment) where it scored a mean overall appearance of 2.9 across the growing season, which is not statistically different from 3.0; the acceptable rating cutoff in our trial. Researchers note that ‘Issai’ suffered from some issues with foliage quality, including yellowing leaves and herbivory, however, rates of pest and disease resistance did not differ across irrigation treatments. Only one flower was observed which did not develop into a fruit. Additionally, this taxon was not very vigorous across the deficit irrigation season, only pushing out a few new leaves at a time. Ratings for this taxon were highly impacted by the slow rate of establishment and growth, and we anticipate that this taxon would display higher performance ratings with a longer establishment time.

Kiwi Magic

Actinidia arguta ‘Issai’ (Kiwi Magic® Hardy Kiwi) is a vigorous, deciduous, woody climbing vine in the Actinidiaceae family derived from a species native to eastern Asia, including Japan, Korea, and Manchuria. This cultivar combination includes a female fruiting plant (A. arguta ‘Issai’) and a male pollinator grown together to improve fruit production. The vine climbs by twining stems and can reach 20–25 ft in height with a spread of 12–20 ft when supported on a trellis or arbor. The plant produces glossy green foliage that forms a dense canopy during the growing season. In late spring to early summer, fragrant white flowers appear along the stems and are followed by small, smooth-skinned edible fruits typical of hardy kiwi. Once established, the vines are fast growing and well suited for covering arbors, fences, and trellises. Actinidia arguta prefers fertile, well-drained soils with consistent moisture and grows best in full sun to partial sun. The species is hardy in USDA Zones 4–8 and is valued both as an ornamental climbing vine and for its edible fruit production.

The Kiwi Magic® vines were transplanted in 2024 as replacement plants. All plants received full irrigation during the establishment period, which supported successful establishment at the site. All vines survived the winter of 2025, indicating good cold tolerance under the conditions of the Logan, Utah trial site. During the following growing season, plant growth was relatively slow, and canopy development remained limited. By the end of the growing season, vines covered approximately 25% of the trellis. No flowering or fruiting was observed during the evaluation period. Because the plants were transplanted later than the other taxa in the trial, they were not included in the open house evaluations.