What Is the Root Length of a Knock Out Rose Bush?

"Knock Out"

• A mature "Knock Out" rose, raised under good conditions, grows 2 to 4 feet tall and spreads 3 to 4 feet. Therefore, the root system of the mature shrub will also have a spread of up to 3 to 4 feet. If the rose is centered in a planting space, with roots spreading outward on all sides, the longest roots would potentially equal the radius of a 3- to 4-foot circle --1 1/2 to 2 feet. It would probably take several years after planting for the roots of a "Knock Out" rose to reach their full length and size.

Planting

• Optimal planting conditions lead to maximum root growth. For containerized roses, dig a hole slightly deeper than the height of the container and twice as wide. Mix organic material with the dirt at the bottom of the hole, fill partially with water and plant the rose so the top of the root ball is even with the top of the hole. If planting a bare-root rose, dig a hole slightly deeper than the height of your spade or shovel and create a mound of compost/soil mixture in it. Arrange the roots over this mound, water and fill the hole.

Container Growth

• "Knock Out" can be successfully grown in a container, provided the container is at least 3 feet in diameter. A half whiskey barrel or tub might work well. Healthy pot-grown specimens need good drainage, so make sure the container has drainage holes and a layer of gravel, pot shards or other drainage material in the bottom (under the soil layer). Potting mix, augmented with organic material, will provide for optimal root growth.

Considerations

• Roots are always a primary consideration when transplanting roses, including "Knock Out." To prevent damage to the root system, make sure that when you dig up the rose, you include a root ball as wide as the plant's crown. The smallest roots may still sustain some damage in the transplanting process, but with adequate water and proper planting, transplant shock will be minimized.