“Royal Frost” (Betula sp.) birch gets the best traits from each of its parents. The beautiful white exfoliating bark from “Whitespire” birch and the deep purple leaves from “Crimson Frost” birch make this tree a wonderful accent piece that provides year-round interest. Hardy to Zone 3 in North America, Royal Frost requires medium to moist conditions and full sun to partial shade. It can grow to a height of 12m, with a 7m spread in an upright-pyramidal to upright-oval shape and is more vigorous than Crimson Frost.
Like its Whitespire parent, Royal Frost has resistance to the bronze birch borer and its purple leaves are said to be unattractive to herbivores, which tend to go for anything green. In spring, the leaves emerge burgundy and turn darker as the leaves mature. The white bark provides a stark contrast to its purple leaves.
The colour is caused by the abundance of anthocyanins found in the leaves, which are pigments that reflect red, purple, and blue. Typically, plants only produce these molecules in the fall to provide sun protection as they try to recover as much anergy and nutrients from their deteriorating leaves. When fall comes, the leaves of Royal Frost turn brilliant shades of yellow, orange and red, as the chlorophyll breaks down, allowing for the carotenes (orange pigment) and xanthoopylls (yellow pigment) to show along with the anthocyanins. During winter, the bare branches looks striking against a blue sky, and dark markings stand out against the snow.
FloraMaxx propagates Royal Frost from tissue culture and plants are available either active in spring or dormant in fall in 2.5”x2.5”x3.25” pots.