Pinus mugo ‘Amber Gold’ originated in a batch of seedlings at Ferny Creek Nursery in Australia. The golden winter color, which changes to almost green in the summer is highly unusual, but not totally unique. There are other conifers that do the same. Why does this happen? According to Bob Fincham, one of the top conifer authorities in the US, cold weather destroys chlorophyll and carotenoids. Green conifers maintain their pigment balance but if the balance is upset by excess carotenoid destruction, the chlorophyll is not protected and is destroyed at an accelerated rate. This results in the yellow carotenoids being dominant, and thus the yellow color. Length of daylight plays less of a role than temperature. Once warm temperatures resume, the green chlorophyll once again dominates.
Pinus mugo, the Mountain Pine, is a subalpine plant of the mountains of central and southern Europe. There are two, possibly three, subspecies over its range. Ssp. mugo is a multi-stemmed plant, while ssp. uncinata is usually single stemmed. The latter is actually recognized as a true species by some authorities. Subspecies rotundata is thought to be a hybrid of the other two. In addition, there is a variety of Pinus mugo called pumilio. It is much smaller than the species, topping out at 3 to 5 feet. Many cultivars have been selected from this variety, including my plant of the week, ‘Amber Gold.’ An additional variety, rostrata, is the same as uncinata.
My plant was obtained from Conifer Kingdom in Oregon in 2018 and is expected to reach a height of 3 feet and spread 5 to 6 feet. Definitely a bright spot in the winter garden. Enjoy!
The Cottage Gardener 