Growing Knock Out Roses

Photo by: Traci Zientara / Shutterstock.

Zones:

Most varieties 5-11, with some possibly hardy to zone 4 if given winter protection

Height/Spread:

3 to 4 feet tall and wide

Exposure:

Full sun

Bloom Time:

Spring through fall

Flower Color:

Shades of red, pink, yellow, and white

When to plant:

Planting in fall or early spring is best for either container-grown or bare root Knock Outs.

Where to plant:

As long as there is enough sunlight, Knock Out roses can be planted just about anywhere in your garden. They will do exceptionally well when planted in south and east-facing areas where they will receive the most sunlight. They will tolerate part shade well; however, flowering may be reduced. Rosa 'Radcor' and Rosa 'Radrazz' are better suited for part-shade locations.

How to plant:

Dig a planting hole to a depth the same as the root ball and about twice as wide. Remove the Knock Out from its container and gently loosen the roots at the bottom. Place it in the ground and backfill the hole. Make sure that the base of the plant is level with the surrounding soil. Finish off by watering thoroughly at the base of the plant. To help retain moisture and block out weeds, a layer of mulch can be placed around the plant.

Soil:

Knock Outs prefer slightly acidic, well-drained soil.

Pruning:

A light pruning to maintain shape and size can be done in late winter or early spring while still dormant. This will help keep your Knock Outs healthy and promote growth in spring. Although deadheading is not needed, it will encourage re-flowering.

Amendments & Fertilizer:

Mature Knock Out roses will benefit from a general purpose or rose fertilizer applied regularly during the growing season. Stop fertilizing a month before your first frost date. Do not fertilize Knock Out roses immediately after planting—it is best to let them establish through a complete bloom cycle first. Read more in our Guide to Fertilizing Roses.

Watering:

Water regularly during the first growing season to allow a good root system to develop. After that, a good guideline is to water when the top 2-3 inches of soil is dry. It is best to water them deeply and in the morning. Although they are drought tolerant, a good layer of mulch will help retain moisture during hot or dry periods.

Diseases and Pests:

Knock Outs have greatly improved disease resistance when compared to traditional tea roses and often require no fungicide treatments.

Winterize:

In most cases, a few inches of mulch is all your Knock Outs will need to protect them over the winter. If temperatures are forecast to drop well below freezing, you may want to cover your Knock Out roses with a frost blanket or wrap them in burlap.