Knockout Rose Companion Plants: What Plant To Grow With Knockout Rose?

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Knockout Roses are easy-to-maintain plants. Being a carefree plant, you can effortlessly plant them in your garden as compared to other categorized rose plants. They are long-seasoned bloomers. Producing impressive blooms from early spring until the first frost. Their eloquent colors consist of red, white, pink, and yellow.

Knockout Roses reach a mature height of about 3 to 4 feet forming thick bushes. Knockout roses are more intricate as they endure heat well and are less vulnerable to pests or diseases.

If you’re wondering how to adorn your garden with plants that complement Knockout roses, read on for our top picks.

Why Does Knockout Rose Need Companion Plants?

Companion planting is a practice of combining plants that benefit and protect each other. Knock Out roses benefit from garden bedfellows that look great, draw in beneficial insects, and ward off pests. Entailing companions in the garden will enhance the following demands:

  • Boost nutrient uptake
  • Maintain pest control
  • Encourage in pollination
  • Increase crop production

Best Knockout Rose Companion Plants

Below are the top pics that go well with Knockout Roses. The companion plants mentioned are:

1. Foxgloves


Foxgloves are tall and biennial plants bearing tubular-shaped flowers. They are short-term perennial plants with various shades of red, yellow, white, pink, purple, and apricot. Its flowers bloom between late spring and early summer.

Foxgloves enjoy companionship with Knockout Roses for soils that drain well, making them grow vibrant alongside. They even share similar light requirements from full sun or partial shade.

2. Marigolds


Marigolds and Knockout Roses enjoy similar growth requirements. They flourish in full sunlight, well-drained soil, and weekly watering during the growing season. They are found in various colors of yellow, orange, and red.

Planting marigolds beside Knockout Roses draws beneficial insects and pollinators. Additionally, they make it easier to prevent pests.

3. Shasta Daisy

Shasta Daisy

Shasta Daisies and Knockout Roses are perennial flowers that grow with little maintenance. They grow in sunny to partial shade for optimum growth. Shasta Daisy blooms during summer. It requires well-drainage, with little moisture content.

Shasta Daisy paired with Knockout Roses is a favorite garden plant that adorns the garden look.

4. Verbenas


They are long-lasting summer blooms that come in shades of blue and purple. Verbenas complement Knockout Roses for their low-growing flowers that hide their lower branches. Verbena is heat tolerant and does well with full sun and well-draining soil, just like Knockout roses.

5. Lavenders


Lavenders add fragrance when planted in any garden. Its purple-blue is appealing to the eyes. Lavenders are hardy flowers, blooming from late spring and throughout the summer.

Lavenders help attract pollinators, bees, and butterflies while deterring rabbits and deer. Moreover, they don’t compete for resources; hence, they don’t hamper the growth of Knockout Roses. Lavenders also keep pests away that may be harmful to your Knockout Roses.

Unlike Knockout Roses, lavenders thrive in well-draining soil and tolerate little drought.

6. Snapdragons


The Snapdragon flowers look like the mouth of a dragon flower, also known as dog flowers. They grow in cool weather and bloom in early spring. Similar to Knockout Roses, they need full to partial shade. Grow Snapdragons in rich, well-draining soils with a neutral or alkaline pH. The water requirement is more than other perennials.

7. Sage


Sage is a shrubby characterized as an ornamental plant. Their greenish-grey leaves produce blue and purple flowers. Knockout Roses share similar grounds with sages as both are low-maintenance and perennial plants.

Grow sage during the cooler seasons, which are spring or fall. Sage enjoys full sun and grows in sandy or well-drained loamy soils with slightly acidic or neutral pH.

Worst Companion Plants For Knockout Rose

Avoiding the worst companions is the best way to protect your garden. Here are the 5 worst companion plants for Knockout Roses.

1. Bunchberry


Bunchberry are an excellent ground cover in a moist woodland garden and are equally attractive when they flower. They are from the small genus of shrubs and trees.

Bunchberry cannot thrive with Knockout Roses as the former needs shade and enough water. Whereas Knockout Roses are heavy feeders, they need nutritious soil lower in nitrogen.

2. Fuchsias


Fuchsias are immensely eye-captivating with their hanging blooms. They consist primarily of shrubs or small trees. Fuchsias require a lot of shade with moist soil, making them unsuitable for planting with Knockout Roses, which need six hours of full sunlight.

3. Toad Lilies

Toad Lilies

Toad Lilies are beautiful flowering plants. They come in various colors that include pink, purple, blue, and white. Toad Lilies should not be planted with Knockout Roses because their growing requirements are unsuitable.

More than a bit of shade does not help Knockout Roses to thrive. So producing these together may need to be more effective.

4. Hydrangeas


Hydrangeas are easy-to-cultivate beautiful shrubs. They are not the best flowers to plant next to Knockout Roses. These papery flowers conflict with what Knockout Roses requires because the former requires moist soil and ample shade to thrive.

5. Large Trees And Shrubs

Large Trees And Shrubs

Large trees and Shrubs amplitude your garden look. Large trees and shrubs take up excess nutrients and water as well as provide shade to other plants. Putting together Knockout Roses with large trees and shrubs can be conflicting.

What Are Knockout Rose Growing Requirements?

The growing requirements of knockout roses are given below:

1. Light


They need plenty of sun exposure for a continuous six hours daily.

  • Ensuring proper light will allow constant blooms.
  • Decent light will further eliminate pests and diseases at bay.

2. Water


Knockout roses have fewer water requirements to keep the plant healthy. However, regular watering is needed for younger plants.

  • Watering the mature knockout rose plant weekly is enough for their decent growth.
  • Avoid over-watering, which causes root decay and further risks the growth of harmful pests and diseases of the knockout roses.

3. Soil


Knockout Roses need well-drained loamy soil for prosperous growth.

  • If needed, use the proper lime application to increase the pH level, whereas use sulfur to lower the pH as required.
  • To maintain good soil health, include organic compost or mulch and supplement with Nitrogen.

4. Fertilizer


A monthly requirement of high Nitrogen fertilizer is required during the growing season.

  • Fertilizing prepares the soil for long-lasting blooms encouraging healthy growth.
  • Start fertilizing when the temperature warms up during spring, as they start developing and budding.

5. Temperature


The temperature Knockout Roses withstand is a cold-hardy temperament. These tough roses can bear heat-tolerant conditions.

  • Insulate the roots during colder climates by laying organic mulch.
  • For winter, stop fertilizing in late summer, although applying a final layer of fertilizer in the fall after flower sheddings.

Grass Diseases And Pests

Knockout Roses are carefree plants in comparison with other rose clans. Having them in your garden is a pleasure as they are disease-resistant plants.

However, there is a need for the induction of some pests and diseases due to poor care, climatic effects, or overwatering can disturb plant growth.

Here are some of the potential diseases and pests that include:

  • Black Spot Fungus
  • Powdery Mildew
  • Botrytis Blight
  • Stem Canker
  • Rust

Measures to be taken:

  • Spraying fungicides at intervals to save your plant from further pests/disease attacks.
  • Monitor the soil, and check the moisture levels following their nutritional requirements for healthy plant growth.
  • Using multiple applications of various pesticides depends on the plant’s needs.
  • Chemicals should be used as a last option, as organic treatments are safer.


The beautiful Knockout Roses is an easy-maintained and pest-resistant plant. Their sweet-smelling blooms keep your garden aromatic for months.

Plants that go with Knockout Roses understand unsuitable plants to avoid. Following this article, learn how to protect your Knockout Roses if not cared for.

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