Double Knockout Roses Plant Care

Roses are fussy, but what if we told you there is a rose that is not so demanding? We can see your eyebrows moving upwards with a frown as you love rose bushes.

Well, the Double Knockout Roses are the cousin to the Knock Out Rose and just as pest resistant to even drought tolerant to some extent.

While gardeners would say these beautiful flowers are easy to maintain, we at Plantly still feel it needs your attention and is less fussy than most other cultivars in the rose family.

Plant Name: Rosa x ‘Radtko’

Other Name: Rosa Radtko or Double Knockout Roses

Plant Type: Flowering Tree or Shrub

Native Areas: Cultivar

Light Requirement: Full Sun to Partial Shade

Watering: Moderate

Fertilizer: Nitrogen-Rich Feed

Toxicity: Non-toxic

Temperature: Down to 10°F

Propagation: Cuttings

Growth: 2-4 feet tall and 3-4 feet wide

Soil Type: Well-Drained Soil

USDA Hardiness Zones: 5-10

More About Double Knockout Roses

The first variety of rose bushes created by William Radler was the Knockout roses in 1989. After that, he wanted to develop tree roses that would last. The Knockout roses were meant to be disease resistant.

He mixed a Floribunda with Razzle and a Carefree Beauty producing a single tier of petals. As a result, the blooms had five petals per flower. Yet, he took it further to create the Pink Double Knock, a variation of the original Knockout.

Compared to other roses, the flowers are fuller as it has two tiers of petals. Thus, the rose bush has a woody form that grows between two and four feet tall to three and four feet wide. As a result, the Knockout roses have a longer bloom cycle flowering most of the year.

Still, it is very thorny, and you need gloves to handle this plant. Neither is it well known for its fragrance or using as a cut flower. But compared to most other roses, it has disease, drought, and pest resistance.

Caring For Double Knockout Rose Bushes

Care is more accessible than the other flowers in the rose bush family regarding Double Knockout Rose. Yet, you still need to follow some vital tips when caring for your new rose.

The Best Soil For Double Knockout Roses

Whether you grow your Double Knockout Rose tree in the garden or on the patio, it needs a neutral soil pH between 5.5 and 6.5.

The most important thing is to find a well-prepared spot; rototilling the ground helps at 12 inches. The crucial thing is to provide well-draining soil, and some organic matter worked in.

For Double Knockout Roses care, provide enough drainage holes in a container and provide them with nitrogen. While these roses are drought resistant, it helps to keep the soil moist.

How Much Sun Do Your Roses Need?

You plant Knockout Roses in full sun and partial shade for outdoor plant care. Yet, these cold hardy roses can still become sensitive to extreme heat.

Getting at least six hours of direct sun is essential for your Double Knock Out Roses.

Beautiful blooms will fill the garden when your roses get enough sun during the blooming season.

Watering Your Knockout Roses

Watering your Double Knock Out Rose in the home garden depends on your climate. Your new flowers will need more sun and water to thrive in the first year. Nonetheless, the soil needs to remain moist but not dry out completely.

Therefore, we recommend deep watering around the rose base and when the top few inches of the soil are dry.

Temperature and Humidity

You can quickly grow Double Knockout Roses in Zones 4 to 10 as they can survive frost and temperatures down to 10°F.

Still, if you get a hard frost, we recommend winter protection from the first wave of frost by covering them with burlap.

The same applies to humidity by giving your roses good air circulation to prevent diseases from forming on the foliage, even if they have disease resistance.

Fertilizing in Early Spring

As you can see, the Double Knockout Roses have the same care as most roses and do not need much feeding. Still, you can feed them in early spring during the growing season. Or invest in a nitrogen-rich feed.

Pruning Tips

The Knockout Roses are self-cleaning and do not need much pruning. The flowers will die and fall to the ground. You can prune off the dead or dying blooms as it will not hurt the container plant.

Alternatively, you can remove the dead or dying branches to allow the greenery to grow bushier. Finally, we recommend removing the crossing branches as it gives the shrub a complete look.

Also, remove the whole branch, as new growth will not develop from the stub left behind. For cut flowers, cut the stem to the base where it grows from the cross branch.

You can also prune your Double Knockout Roses to keep them in a compact size.

Propagating Knock-Out Roses

A great way to propagate your Knock Outs is using cuttings by taking a tip cutting where the hip forms.

• Cut a six-inch long cutting at a 45° angle and leave it to dry.

• Find a sunny location with partial shade and mix compost pine bark with peat moss in the ground.

• Ensure there is good drainage and keep the soil moist. Remove the lower leaves on the cutting and dip that end into a rooting hormone.

• Then plant the cutting into the ground or in a container and leave it in that spot for up to a year before transplanting it.

Knockout Roses Similar Plants

The Double Knockout Roses are not the only hardy flowering shrub in the rose family. Here are some other selections you can grow in your garden:

The Original Knock Out

The rose is powdery mildew and black spot resistant with hot pink or cherry red single blooms.

Pink Knock Out

You will find this rose in a single to double flower in a bright pink color that is drought resistant.

Blushing Knock Out Roses

A single pink flower that fades over time.

Rainbow Knock Out

The shrub has a compact growth with coral-pink flowers with yellow centers.

Sunny Knock Out

The rose is famous for its citrus fragrance and blooms yellow-cream flowers.

sunny knockout rose @fuzzjay

Double Knockout Roses Common Diseases and Pests

While the Double Knock Out Roses are not bothered by many pests or diseases, they can still get bacterial infections and insects bothering them.

When you notice a black spot on the leaves, it can result from high humidity, and it will start dropping leaves. Water your roses at the base and not over the foliage.

While powdery mildew can occur in spring and fall, it will start by coating the leaves, stems, and buds with a white color. It also results from high humidity.

Also, watch the Japanese beetles, mealybugs, aphids, rose slugs, and spider mites, as they can still travel from other plants in the garden to your roses.