Abstract

Three structureless row covers (white, spunbonded polyester and two weights of white, spunbonded polypropylene) were evaluated for winter protection of container grown ‘Helleri’ holly (Ilex crenata ‘Helleri’), ‘Atropurpurea Nana’ nandina (Nandina domestica ‘Atropurpurea Nana’), Fraser photinia (Photinia × fraseri), and ‘Mohave’ pyracantha (Pyracantha Koidzumii × coccinea ‘Mohave’) relative to white copolymer film and white copolymer backed thermoblanket over quonset-shaped structures and an unprotected control. Air and rooting medium temperatures were monitored during the deployment period. Visual foliar injury ratings were taken immediately after treatments were removed and again four months later. Visual shoot injury ratings were correlated with the mean daily average and the mean daily minimum temperature of air and rooting medium within each treatment. Both polypropylene covers provided protection for plants in the interior of a consolidated group equivalent to white poly and the thermoblanket for all species except Pyracantha. Porous row covers are a feasible alternative to standard protection systems.