I debate taking actions to protect marginally cold hardy evergreens planted this year. The overriding philosophy of this garden has long been “survival of the fittest”, and without a doubt, constructing leaf filled cages to insulate fatsias and Anise shrubs (Illicium floridanum ‘Pink Frost’, below) is contrary to three decades of trial and error in determining plants sturdy enough to survive with a bare minimum of the gardener’s intervention.
I suspect that Anise shrub , and certainly fatsia (Fatsia japonica ‘Spider’s Web’, below), are over promised as cold hardy to zone 7. Of course, I could do nothing, depend on references that state they’re cold hardy, and see what happens. In recent years I’ve verified, at least to my satisfaction, that gardenias rated as zone 6 cold hardy, are not, and should hardly be considered as hardy to zone 7 (zero degrees Fahrenheit) . But, this required allowing the gardenias to overwinter, and perish, without protection. What is an “I told you so” worth?
A Japanese anise shrub (Illicium anisatum ‘Murasaki-no-sato’ Purple Glaze, below) survived several years in the garden until being overwhelmed by more vigorous neighbors. The cold didn’t kill it, but a lot of energy was expended recovering each spring. Probably, this shrub would have more vigor one hardiness zone to the south, and I expect a similar result from the southeastern U.S. native.
Both Anise shrub and the fatsia have variegated foliage, which typically diminishes vigor and further limits cold hardiness, and new plantings are more vulnerable to cold until roots are well established. So, it is a bit unreasonable to expect these marginally cold hardy shrubs to survive their first winter in the garden without assistance.
So, constructing leaf filled cages is probably a good bet, at least in this first year after planting. No purpose is served by leaving the fatsias and Anise shrubs to go unprotected, and certainly there are plenty of leaves covering the garden to fill the cages. Whether this will be enough to get them through the winter, we’ll find out.