'Marvel' Mahonia

Mahonia × media 'Marvel'

Mahonia ‘Marvel’ on low water in 50% shade in May in Davis. Photo: SK Reid.

Summary

Mahonia ‘Marvel’ is a shrub composed of layers of stiff green leaves with a prickle at each tip. These are arranged along upright, unbranching stems. The new buds emerge almost cycad-like and grow in a vertical fashion reaching a shape reminiscent of a closed fan. Then the tight growth bursts open revealing a cluster of soft fleshy leaves colored either fresh chartreuse or earthy, copper-brown, depending on their stage of growth. In early winter this plant hosts racemes of yellow flowers followed by clusters of small, oblong blue berries. Flowering did not occur during the first or second winter during the trial. Through happenstance we left roughly half of the plants in the ground, and this most recent winter (their third), all remaining plants flowered.

No significant differences in relative growth were observed between the treatments (Figure 17b). The quality ratings also showed no differences between treatments, making this truly a low-water plant. Rust pustules were observed using microscopy on some plants during the establishment year, but it was completely outgrown in the second year and no evidence of it was later found. In the late winter/early spring of 2019, researchers observed what appeared to be thrips damage, indicated by misshapen new growth with gray necrotic portions remaining on the leaves as they aged. While mature growth on this cultivar is thick and stiff, new growth is fairly tender and fleshy making it more prone to early pest damage. This pest issue weighed down the foliage quality, pest resistance, and overall appearance scores, but there was no irrigation treatment effect related to it, yielding very good scores late in the season (Table 23a), and no lasting effect on plant health. As the plants grew and new growth covered damaged foliage, scores improved to very good by September. This pest issue had not been observed by our cooperator or the primary investigator who planted it in her own garden and may be unique to our situation where roses are hosts to a healthy thrips population. Foliage damaged by the stiff leaves scraping or piercing the leaflets below them in the wind was also observed. That said, ‘Marvel’ attracted many admirers due to its strong architectural stature and striking presence, and from a distance the foliage damage was all but unnoticeable. Based on participants votes, ‘Marvel’ was voted the favorite plant at the summer open house and came in second at the spring and fall events. The striking foliage and form along with the interesting changes during the season also made this a staff favorite. Based upon our results we recommend irrigating ‘Marvel’ on low water in WUCOLS zone 2.

Growth and Quality Data

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Mahonia ‘Marvel’ on low water in 50% shade in October 2019 in Davis. Photo: SK Reid.