How Big Can Knock Out Roses Get?

Do you want to add some knockout beauty to your garden? Get ready to be blown away by the Knock Out Rose!

This stunning flower is a must-have for any garden enthusiast.

With its ease of care and breathtaking blooms, it's no wonder this rose is a popular choice among gardeners.

But before you start planting, it's important to know just how big this beauty can grow.

In this article, we'll explore the different sizes of Knock Out Rose and provide tips on how to care for them so you can enjoy their stunning blooms all season long.

' Coral Knock Out ' Rose flowers in field, Ontario, Canada., Size Matters: How Big Can Knock Out Roses Get?

How Big Do Knock Out Roses Get?

Knockout Roses Denver Botanic Garden

Knock Out Roses are a popular choice for gardeners because of their easy-care nature and disease resistance.

But, how big do they actually get? Let's take a closer look at the different types of Knock Out Roses and their sizes.

Petite Knock Out Roses

Petite Knock Out Roses are the smallest of the Knock Out family, growing to be about 18 inches tall and wide.

These miniature roses are perfect for small gardens, containers, or as borders.

Despite their small size, they still produce the same beautiful blooms as their larger counterparts.

Miniature Knock Out Roses

Miniature Knock Out Roses are slightly larger than Petite Knock Outs, growing to be about two to three feet tall and wide.

These roses are perfect for those who want a compact rose bush that still produces plenty of blooms. They are also great for containers or as borders.

Double Knock Out Roses

Double Knock Out Roses are the largest of the Knock Out family, growing to be about three to four feet tall and wide.

These roses produce stunning double blooms that are sure to catch the eye. They are perfect as specimen plants or as a focal point in the garden.

It is important to note that while these are the typical sizes for Knock Out Roses, they can vary depending on growing conditions, pruning, and other factors.

Whether you choose Petite, Miniature, or Double Knock Outs, you are sure to enjoy their beauty and easy maintenance.

How to Maintain Knock Out Roses

Closeup of Pink Knockout Roses in a Garden


Water your roses regularly, especially during the hottest months of the year.

They prefer to be watered deeply but infrequently, so make sure the water reaches the root zone. Avoid getting the leaves wet, as this can lead to fungal diseases.


Knock Out Roses benefit from regular fertilization to promote healthy growth and abundant blooms.

Apply a balanced fertilizer in early spring and again in mid-summer.

Be careful not to over-fertilize, as this can lead to excessive foliage growth and fewer blooms.


Prune your roses in late winter or early spring to remove dead or damaged wood and encourage new growth.

Remove any canes that are crossing or rubbing against each other, as this can lead to disease. You can also shape the plant to your desired size and shape.

Pest and Disease Control

Knock Out Roses are generally resistant to pests and diseases, but they can still be affected by common problems like aphids, spider mites, and black spot.

Keep an eye out for any signs of infestation or disease, and treat them promptly with an appropriate insecticide or fungicide.

Winter Care

Protect your roses during the winter months by adding a layer of organic mulch around the base of the plant.

This will help insulate the roots and protect them from freezing temperatures. You can also cover the plant with burlap or another breathable material to protect it from wind and cold.

By following these simple maintenance tips, you can keep your knockout roses healthy and beautiful year after year.

What Kills Knock Out Roses?

Rose pruning in spring

Several factors can kill Knock Out Roses, including:

Black Spot Fungus

This is a common disease that affects Knock Out Roses. It is caused by a fungus that thrives in warm, humid weather.

Symptoms include black spots on the leaves, which eventually turn yellow and fall off. To prevent black spot fungus, keep the leaves dry and remove any infected leaves.

Botrytis Blight

Also known as gray mold, this disease is caused by a fungus that attacks the flowers and buds of knockout roses.

Symptoms include brown spots on the flowers, which eventually turn gray and fuzzy.

To prevent botrytis blight, get rid of any infected flowers and buds.

Powdery Mildew

This disease is caused by a fungus that thrives in warm, dry weather. Symptoms include a white, powdery substance on the leaves and stems of knockout roses.

To prevent powdery mildew, keep the leaves dry and remove any infected leaves immediately.


This disease is caused by a fungus that attacks the leaves of knockout roses. Symptoms include orange or brown spots on the leaves, which eventually turn black and fall off.

To prevent rust, keep the leaves dry and remove infected leaves.

Stem Canker

This disease is caused by a fungus that attacks the stems of knockout roses.

Symptoms include sunken, black areas on the stems, which eventually cause the stems to wilt and die.

To prevent stem canker, keep the stems dry and remove any infected stems.

It is important to note that proper care and maintenance can go a long way in preventing these diseases from affecting your roses.

Make sure to water them regularly, prune them regularly, and fertilize them as needed. Also, be sure to plant them in an area that receives plenty of sunlight and has good drainage.

If you do notice any signs of disease on your knockout roses, it is important to act quickly to prevent the disease from spreading. You may consider using a fungicide to treat the plant.

How Fast Do Knock Out Roses Grow?

Knockout Roses

Knock Out Roses are known for their fast growth. They can grow up to two feet tall and wide in just one season.

However, the exact growth rate will depend on a variety of factors, including the specific variety of rose, the growing conditions, and how well they are cared for.

How Much Space Do Knock Out Roses Need?

Most Knock Out Roses should be spaced three to four feet apart to allow for their mature size and good air circulation.

This will help prevent disease and ensure that your roses stay healthy and beautiful.

How Long Do Knock Out Roses Live?

Knock Out Roses are known for their robust nature and ability to bloom for extended periods. They are also known for their relatively long lifespan.

A Knock Out Rose can have a lifespan of three to five years. However, with the right care, they can live for much longer—up to 10 years or possibly longer.

The lifespan of Knock Out Roses can vary depending on several factors, including the variety of the rose, the climate in which it grows, and the care it receives.

Some varieties of Knock Out Roses have a longer lifespan than others. The Double Knock Out Rose, for example, can live up to several decades with proper care.

It is important to note that even with proper care, Knock Out Roses will eventually reach the end of their lifespan. When this happens, you can replace them with new plants to ensure continued beauty in your garden.

Check out these related posts:

11 Types Of Knock Out Roses

Which Roses Are Best For Windy Areas?

A tip of the trowel to OpenAI's ChatGPT for helping cultivate this article.

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