When to Plant Knockout Roses – Planting Guide 2024

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If there is a shrub rose cultivar that beginner and experienced home gardeners love, it’s Knockout roses.

And it’s understandable.

From its extended blooming season to increased disease resistance, you’ll find many reasons to love this garden staple.

The best part? They don’t require much care and maintenance, as long as you plant them at the right time.

When to plant Knockout roses? The best time to plant Knock Out roses is in late winter or early spring. This way, your rose bushes will have enough time to establish strong roots before the summer heat sets in. If you are growing container Knock Out roses, you can plant as late as late spring.

Planting Knockout Roses in Different Climates

The good thing about Knockout roses is that they easily adapt to various environments and will thrive in different climates with not much issue.

As long as you plant them in well-draining soil and provide them with 6-8 hours of full sun, they will have the best chance of surviving.

If growing in areas that get extremely hot weather, you will want to water your roses regularly and keep the soil moist.

On the other hand, while still possible, planting Knockout rose bushes in colder climates will require a little more care.

You can keep them protected against freezing temperatures and piled-up snow by covering them with boxes.

In case that’s not doable, you can manually clear the snow so that the stems don’t have a hard time carrying all that weight.

Alternatively, you can choose to plant them in containers and bring them indoors during particularly harsh weather.

Choosing Knockout Roses Seeds

In choosing which Knockout rose variety to grow, make sure you only buy seeds from Star Roses and Plants.

Also known as the Conard-Pyle Company, they hold the patent and are the official sellers of this rose shrub cultivar.

You will have three choices when it comes to growing Knockout roses.

You can start them from seeds, plant bare-root plants, or transplant already-established rose bushes from a container.

If you are confident enough to start Knock Out roses from seeds, you will probably be able to buy them from your favorite local garden store.

Once you have them, you’ll want to carefully pick the seeds that have the best chance of germinating.

To do this, get a jar with water and put a handful of the seeds in it.

Those that float to the top are the ones that are less likely to germinate, so you’ll want to throw those away.

You will then be left with the healthy ones, which you will need to either chill or stratify.

How to Plant Knockout Roses Seeds

Knock Out roses come in different varieties, letting you grow multi-colored, bright red, yellow, or pink flowers to add life to your home garden.

After acquiring the seeds, the next step is making sure you time the planting and growing process correctly.

Here’s the step-by-step guide to planting these beautiful flowering plants:

Step 1: Stratification

While known for their hardiness, you will have greater chances of growing healthy Knockout rose bushes if you stratify the seeds beforehand.

Aptly termed “waking up the seeds,” stratification allows the seeds to survive the cold winter and germinate only when the conditions have become more favorable.

To do this, simply place the seeds in a folded, moist paper towel or moist peat moss, making sure there’s ample space in between.

Then, place that in a container and store it in the fridge for about a month or two.

Ensure the container has holes to allow for ventilation and prevent the growth of mold.

Step 2: Germinating the Seeds

After about 45 to 60 days, you’ll know that your seeds are ready for germination.

In a container with about an inch of potting mixture, plant the seeds 1/4-inch deep and water the container afterward.

Then, place the container outdoors under direct sunlight.

During particularly frosty mornings, transfer the container under a tree or on a patio to protect the seeds from the cold.

In about six weeks, you can expect to see sprouts.

Wait until they reach three inches tall before transplanting them into individual pots or their permanent outdoor spot in your garden.

Step 3: Picking the Right Spot

Though hardy, a Knockout rose bush needs 6-8 hours of sunlight every day to ensure it stays healthy.

This is where choosing the right location for your plants will come in.

Determine which part of your garden gets that much direct sunlight.

At the same time, you will also want to make sure that the soil drains well and quickly.

To check, dig a hole around 18 inches deep and fill that hole with water.

If you still find water in the hole after 24 hours, you’ll need to pick another location.

Alternatively, you can plant your Knock out roses in raised beds around one to 1.5 inches high.

Step 4: Planting the Seedlings

To plant the young rose bushes, dig a hole slightly bigger than the base of the plant.

Then, take the plant out from its container and gently loosen the roots.

Place the rose in the hole and add in the previously dug soil, making sure you firm it up around the roots.

STEP 5: Water DEeply After Planting

After planting, water the base of the plants thoroughly and let the water seep in.

How to Water Knockout Roses

Like any other young plant, newly planted rose bushes require watering at least every other day for the first few weeks.

During especially dry couple of days, we recommend that you water them a little more to make sure they don’t dry out.

The key is making sure the soil stays moist but not overwatered, which could result in root rot.

Here are more proven tips when it comes to watering Knock out roses:

Tip 1: Do Overhead Watering From Time to Time.

During the summer season, your rose bushes will benefit from overhead watering once in a while as opposed to watering at ground level.

If you decide to do this, do so in the morning to allow the foliage to dry before night falls and the temperatures lower.

Tip 2: Double the Amount of Water When It’s Hot.

When growing any plant, it’s very important that you don’t allow the soil to dry out for long periods between waterings.

This is especially true during hot days.

In such cases, it would be for the best if you give your rose bushes plenty of water but don’t overdo it.

Allow the soil to dry in between to avoid overwatering.

Think of it as giving your Knock Out roses a long, thirst-quenching drink rather than tiny amounts of water from time to time.

The water should be absorbed by the soil down to around 18 inches deep.

Tip 3: Water About a Foot Beyond the Edges of the Branches.

As your rose shrubs grow, their root systems will extend out.

Hence, it is a good idea to distribute the water about one foot beyond the branches.

This way, you can be sure that every inch of the root system gets enough hydration.

Tip 4: Water Less as They Grow.

For the first two years of its life, you will need to water your Knock Out rose bush every time the top of the soil dries out so that it stays healthy.

However, after this time, it will require less and less watering that it can go a week without hydration.

You’ll know you are watering too much when the leaves start turning yellow and become droopy.

How to Grow Knockout Roses

Knockout rose bushes are considered hardy plants and don’t require much maintenance.

Still, giving them extra attention won’t hurt but, instead, contribute to their overall health.

Here are more expert tips when it comes to growing these perennials:

Tip 1: Pruning

Like any cultivar from the rose family, Knock Out roses will benefit from regular pruning.

Doing so will encourage new growth and allow for better ventilation in and around the thick foliage.

Pruning also lets you reshape the bushes and cut away useless interior branches to make them more presentable.

Tip 2: Fertilizing

Spring is the best time to give your rose bushes some fertilizer.

Often, you’ll need a feed exclusive for roses with a ratio of 4-8-4 or 5-10-5.

Simply spread about half a cup of fertilizer on top of the soil around the base of the plants before watering them.

Then, you’ll want to repeat this step when you see the first buds beginning to appear.

Avoid feeding them with fertilizer in the late summer or fall, as the new stems won’t have enough time to grow before winter.

How Long Do Knockout Roses Take To Grow?

Knock Out roses are hybrids known for being moderate to fast growers.

With proper nutrition, regular watering, and enough sunlight every day, you can expect about two feet of growth every year.

Take good care of them, and they will easily last for more than a decade.

They are resistant to diseases and pests for the most part, but it would also help if you check for these from time to time.


With its brightly colored blooms, any home gardener will love to have Knock Out roses in their garden.

Besides being low maintenance, you can easily multiply them by planting cuttings.

You can also give them away to friends and family to add to their own gardens.

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