Knock Outs, cultivated by Wisconsin botanist William Radler and released commercially in 1999, are hardy, self-pruning, both cold- and heat-tolerant, veritably drought-resistant—they even thrive on benign neglect. Early versions, like the original red cultivar, burst forth in layers of single blooms, while later iterations have multi-rows. The best part? Many bloom from March right through to December.
Cultivar: Knock Out
Zones: 4 -9 (winter hardy to zone 5)
Shape: Compact shrub (3 x 3 feet)
Bloom Size: 3 inches across
Varieties: • Knock Out Rose (red) • Double Knock Out Rose (red) • Pink Knock Out Rose • Pink Double Knock Out Rose • Rainbow Knock Out Rose (pink and yellow) • Blushing Knock Out Rose • Sunny Knock Out Rose (yellow)
Plant in a sunny spot in the spring, once the ground has thawed.
Cover the lower few inches (where the branches stem out from the rose’s base) with dirt and mulch.
Trim judiciously once established, coaxing into your ideal shape and size (never to below a foot tall).
Remove excess mulch once temperatures warm consistently.
Water at its base (not on its leaves) to avoid mildew. But keep in mind Knock Outs are drought tolerant and thus don’t need babysitting; ideally soil is well-drained and moist, but not drenched.
Cover roots with mulch again in the winter.