- 1). Stop fertilizing your Double Knock Outs at the end of August. Fertilizing after this date will stimulate new growth likely to be burned by the coming frost.
- 2). Taper off your watering frequency starting in early September. Water one last time just after the first frost. Then stop watering altogether until growth starts again in spring. This slow tapering off of water sends a signal to the plant that it is time to enter dormancy.
- 3). Mound soil or aged compost around the plant right after the first freeze. Double Knock Out roses growing in zones 6 and higher, where winters rarely fall below freezing, need 4 to 6 inches of organic mulch mounded around the base and over the center of the plant, between the canes. Double Knock Out roses growing in zones 5 and lower benefit from heavier protection. Mound soil 10 to 12 inches high around the base and over the center of the plant, between the canes. Once the soil mound freezes, top it with 12 to 16 inches of organic mulch. This added protection will help the Double Knock Out bush weather the freeze/thaw cycles that are the most damaging to plants.
- 4). Remove the protective mulch layer in spring when temperatures warm.
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