The plant of the month for April is Crimson Frost Birch. It wasn’t all that long ago that northerners looking for a dominant purple-leaved accent tree for their landscapes had only a couple of options from which to choose; a Crimson King maple or maybe a Shubert Chokecherry, and that was about all. Now, recent hybridizing efforts have opened up new alternatives for northern landscapers, and this month, we’re going to tell you about one of the very best.  Crimson Frost birch is a hybrid between the older Purple Rain birch (Betula pendula “Purple Rain”) and the Japanese white birch of “Whitespire” fame (Betula platyphylla var. japonica). It’s rich foliage color is actually a slight improvement over the Purple Rain birch and it has a much more refined, narrowly upright shape, but it’s real improvement is its dramatically increased resistance to the dreaded bronze birch borer.