Some gardeners cover azaleas and camellias, especially when in bloom, during a hard freeze. The plants will survive covered or not, but frost will ruin any flowers. I never cover the other shrubs. Perennials that tolerate temperature extremes include coneflowers, daylilies and leopard plant, which is a shade plant.ome gardeners cover azaleas and camellias, especially when in bloom, during a hard freeze. The plants will survive covered or not, but frost will ruin any flowers. I never cover the other shrubs. Perennials that tolerate temperature extremes include coneflowers, daylilies and leopard plant, which is a shade plant.