Distylium myricoides × racemosum

Among the various Distylium seedlings purchased around 2000 by Michael Dirr of the University of Georgia from Piroche Plants in Canada, who had introduced D. myricoides directly from China in 1995 (Piroche Plants 2023), one sapling stood out for its features which seemed intermediate between D. myricoides and D. racemosum. This was vigorous, reaching 2.5 m after five years, and seemed hardier than pure D. racemosum, and it was also particularly fertile. Its hybrid origins were confirmed by Donglin Zhang, also at the University of Georgia, using molecular markers (Dirr 2015). There is an implication that D. racemosum was the pollen parent in this case – Dirr had ordered Piroche’s D. myricoides selections plus just one plant of D. racemosum – but in this entry the parents are simply listed in alphabetical order.

This accidental cross seems to have unlocked the full potential of this genus’ remarkably protean nature, along with a good helping of ‘hybrid vigour’. The seedlings – there are now several generations – show all manner of habits and foliage features. Some have very blue leaves, some are dark and glossy; one is variegated; the red and purple tints of the unfolding leaves can be particularly showy. Some are low and dense and suitable for groundcover, others are compact and rounded, and by 2022 several fastigiate clones were under evaluation (Dirr 2022). In common with other distyliums these hybrids are subject (as yet) to very few pests and diseases, and their leaves are unpalatable to deer and rabbits; they tolerate the heat and humidity of the American South, even in full sun, and can cope with waterlogged conditions better than most of their relatives (Barnes 2023). They tend to be marginally hardier than D. myricoides itself, with EMERALD HEIGHTS™ and CINNAMON GIRL™ perhaps the toughest (Dirr 2015).

As the generally unpronounceable cultivar names may suggest, these clones are unashamedly commercial artifacts, intended for mass planting within low-maintenance landscaping schemes as replacements for disease-ridden boxes and hollies; they are selected to grow quickly to a maximum size without the need for pruning. As such, they may not necessarily interest the private gardener, and are unlikely to interest the amateur botanist. They represent a fast-growing horticultural subsector and the list below only includes selections which had been commercially released by 2023.