Growing The Yellow Knock Out Rose

Knockout roses are a beautiful, lower-maintenance alternative to the classic rose. Easy to grow and not too picky, these beautiful flowers will bloom all season long with no complaint.

The Yellow Knockout Rose, also named “Radsunny”, the Sunny Knockout Rose, and Yellow Double Knockout Roses, comes from the genus Rosa.

Full Bloomed Yellow Knockout Rose in Midwest GardenPin
Full Blooming Yellow Knockout Rose (Midwest Garden) | Brittany-Adobe

This genus is a collection of has over 150 deciduous shrubs that produce fragrant flowers along their thorny stems.

The yellow knockout rose is winter hardy between USDA Zones four to eleven.

Yellow Knockout Rose Care

Below are tips on how to take care of yellow knockout roses:

Size And Growth

Pastel cream to yellow knock out rose bushes grow up to 3′ – 4′ feet high and 3′ – 4′ feet wide if planted in sunny locations with nutrient-rich, well-drained soil. Prune these bushes back every year to encourage fuller growth.

If planted in containers, your rosebush will outgrow its container every two to three years until it reaches maturity.

Flowering And Fragrance

The yellow flowers of knockout roses brings beauty and color to exterior locations such as:

  • Borders
  • Hedges
  • Flowerbeds
  • Container flower gardens

Bloom color varies from a creamy yellow to a soft cream against a backdrop of dark green, glossy leaves. The cooler the weather, the more yellow the flower appears.

During its nearly continuous bloom period, the yellow knockout flowers emit a sweet citrus scent.

Light And Temperature

Yellow knockout roses grow best when they can feed on plenty of sunshine. Plant them in a sunny location outside, where they have access to direct sunlight at least six hours a day.

They will also grow in shaded areas but may not reach their potential or bloom as well.

Yellow knockout roses do not do well with freezing temperatures. If you live in an area that experiences cold winters, move container plants to a shed, garage, greenhouse, or similar structure to protect them

Watering And Feeding

Make sure your roses get plenty of water, whether they are in a container or the ground.

In regions that receive consistent rainfall, such as the Midwest, this isn’t an issue. In drier regions, give extra waterings.

For containerized roses, water them at least twice a week. During warm or windy weather, you may need to water them daily.

Like all shrub roses, knockout roses love nutrient-rich soil.

Improve soil by fertilizing your knockout rose bushes with granular fertilizer or fish emulsion. But, stop applying late in the season, so you don’t encourage new growth before its winter dormancy.

Soil And Transplanting

Yellow knockout roses need rich soil to thrive.

When planting, spread compost on the planting site, but not directly in the hole for the knockout.

If planting in a container, use a mix of compost and potting soil, ensuring the mixture is a well-draining one.

If transplanting your yellow knockout roses outside, do this early or midseason. This will give the roots time to re-establish themselves in the new area before winter.

Grooming And Maintenance

Deadheading is not required with yellow knockout roses because the petals fall off on their own. Yet, you may trim the flowers that have not yet fallen but are past their prime.

Prune these Knock Out bushes back every year down to 1′ to 2′ feet and watch them grow back bushier next season.

To allow air and sunlight to move throughout a very thick plant, clip out select stems.


One major disadvantage of the Knockout Rose varieties is that they don’t attract bees. This may seem like a bonus for many, but honeybees, in particular, are an essential part of our natural ecosystem.

Pests or Diseases

A significant benefit of knockout roses over regular roses is their high disease resistance. Black spot and powdery mildew do not affect knockout roses for the most part.

But pests can ravage knockout roses as much as regular roses. Aphids and Japanese beetles on Knockout Roses are the biggest culprits.

Aphids may appear to be a problem early in the growing season but often die thanks to other insects that eat them. Trap or pick off Japanese beetles to get rid of them.

Read our article: Diseases on Knock Out Rose Bushes

Bottom Line

Yellow knockout roses produce many cream to yellow colored flowers all season long. They self-clean so you don’t need to deadhead.

Knockout roses, in the ground or in containers, are a great choice for a beautiful low-maintenance rose variety.

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