Double Knock Out® Rose Tree

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Double Knock Out Rose Tree is a striking, tree-form rose known for its vibrant, double-petaled red blooms and elegant, upright structure. Its disease resistance and long flowering season make it a standout feature in gardens, providing a bold and colorful focal point.

  • Botanical name: Rosa ‘Radtko’
  • Bloom time: Spring to frost
  • Evergreen (in warmer climates)
  • Grown in the USA

SUNLIGHT:
Prefers full sun

WATER:
Water when the top 1-2 inches of soil are dry. Approximately every 1-2 weeks. Watering frequency may vary based on climate and establishment phase.

IDEAL CLIMATE:
Hardy in USDA Zones 5-11; thrives in temperate to warm climates with well-draining soil

Note: Double Knock Out Rose Tree may require occasional pruning to maintain its tree shape and encourage healthy growth.

PLANT DESCRIPTION & MATURE SIZE

The Double Knock Out Rose Tree, scientifically designated as Rosa 'Radtko', elevates the beloved qualities of Knock Out roses into a striking tree form. This exceptional variety is celebrated for its abundant, double-petal blooms that offer a continuous display of vivid cherry red flowers from early spring until the first frost. Known for its robust disease resistance, particularly to black spot and powdery mildew, the Double Knock Out Rose Tree combines the low-maintenance and hardiness of Knock Out roses with the elegant appeal of a standard tree. Its compact size and manageable growth make it an ideal choice for accentuating patios, entries, and garden focal points, providing unparalleled beauty with minimal care.

GROWTH RATE & MATURE SIZE:

Moderate growth rate; reaching a mature height of 4-5 feet and canopy achieving a mature spread of 3-4 feet.

Sizing: Our patio rose trees are primarily utilized as outdoor patio plants and are potted. Accordingly, we measure our rose trees from the bottom of the pot to the top of the tree for accuracy.

WATERING & SUNLIGHT

Water regularly during the first growing season to establish a deep, extensive root system; thereafter, it is drought-tolerant, requiring only occasional watering. Requires full sun for optimal growth and blooming.

PLANT CARE & PLANTING INSTRUCTIONS

Pruning: Light pruning in late winter or early spring helps maintain shape and promotes vigorous new growth. Deadheading is not necessary as it is a self-cleaning variety.

Fertilization: Apply a balanced, slow-release fertilizer in early spring to encourage healthy growth and abundant flowering.

Winter Protection: Apply a layer of mulch around the base of the tree to insulate the roots and conserve moisture. Consider using a protective cover or wrapping the tree with burlap to shield it from harsh winter conditions.

PLANTING INSTRUCTIONS:

Choose a sunny location with well-draining soil. If planting in a container, ensure it is large enough to accommodate growth and has drainage holes. Water thoroughly after planting and mulch around the base to conserve moisture and support overall health.

USDA GROW ZONE:

Zones 5-11

The Double Knock Out Rose Tree is adaptable to USDA Zones 5-10, thriving in well-drained soil and requiring at least six hours of direct sunlight daily. Its versatility and durability make it suitable for various landscape applications, from residential gardens to public spaces.

Frequently Asked Questions

The Double Knock Out Rose tree typically grows to a mature size of about 3 to 4 feet in height and spread, forming a compact and bushy shrub. However, in ideal growing conditions with ample space and proper care, it can reach slightly larger dimensions, possibly up to 4 to 5 feet in both height and spread. Pruning can also influence its size and shape, allowing gardeners to maintain it at their desired height and spread.

The Double Knock Out Rose tree is known for its relatively fast growth rate. Under optimal growing conditions, it can grow anywhere from 1 to 2 feet in height per year. However, growth rates may vary depending on factors such as climate, soil quality, and care practices. With proper care and maintenance, Double Knock Out Rose trees can establish quickly and develop into beautiful, bushy trees with abundant blooms.

The best place to plant Double Knock Out Rose trees is in a location that receives plenty of sunlight, ideally at least 6 hours of direct sunlight per day. Choose a spot with well-draining soil to prevent waterlogging, as these roses prefer slightly acidic, fertile soil. Additionally, ensure there is adequate air circulation around the plants to minimize the risk of fungal diseases. Plant them in garden beds, borders, or containers where they can be showcased and provide a stunning display of blooms throughout the growing season.

Taking care of a Double Knock Out Rose tree involves several key steps:

Watering: Provide consistent watering, especially during dry spells or hot weather. Water deeply to encourage strong root development.

Fertilizing: Apply a balanced fertilizer formulated for roses in spring, just as new growth begins. Follow the manufacturer's instructions for application rates.

Pruning: Prune in late winter or early spring to remove dead or damaged branches and shape the plant. Deadhead spent flowers regularly to encourage continuous blooming.

Mulching: Apply a layer of organic mulch around the base of the plant to conserve moisture, suppress weeds, and moderate soil temperature.

Pest and Disease Control: Monitor for common pests like aphids, spider mites, and Japanese beetles. Treat as necessary with insecticidal soap or horticultural oil. Watch for signs of diseases like powdery mildew or black spot and address promptly with appropriate fungicides.

Winter Protection: In colder climates, consider providing winter protection by mulching around the base of the plant and covering with burlap or other insulating material to prevent winter damage.

Sunlight: Ensure the plant receives adequate sunlight, ideally at least 6 hours of direct sunlight per day, for optimal growth and blooming.

By following these care guidelines, you can help your Double Knock Out Rose tree thrive and produce beautiful blooms throughout the growing season.

Yes, pruning Double Knock Out Rose trees is recommended to maintain their shape, promote healthy growth, and encourage continuous blooming. Pruning should be done in late winter or early spring before new growth begins. This helps remove dead or damaged branches, encourages new growth, and stimulates flower production. Additionally, regular deadheading of spent flowers can also prolong blooming and keep the plant looking tidy.

Double Knock Out Rose trees are known for their prolific blooming habit, which typically results in multiple bloom cycles throughout the growing season. In favorable conditions, they can bloom from spring to fall, providing a continuous display of beautiful flowers in the garden.

The Double Knock Out Rose tree produces double flowers in a stunning cherry red color. These vibrant blooms add a bold and eye-catching display to gardens, landscapes, and flower arrangements.

For Double Knock Out Roses, a balanced fertilizer specifically formulated for roses is ideal. Look for a fertilizer with an N-P-K ratio (nitrogen, phosphorus, potassium) of around 10-10-10 or similar, which provides essential nutrients for healthy growth and abundant flowering. Additionally, choosing a slow-release or granular fertilizer can provide consistent nutrition over an extended period, reducing the need for frequent applications.

When fertilizing Double Knock Out Roses:

Timing: Apply fertilizer in early spring when new growth begins and again in late spring or early summer to support the first bloom cycle. Avoid fertilizing late in the growing season, as this can encourage tender new growth that may be susceptible to frost damage.

Application: Follow the instructions on the fertilizer package for proper application rates and methods. Typically, you'll sprinkle the fertilizer evenly around the base of the plant, then water thoroughly to help the nutrients penetrate the soil.

Additional Nutrients: In addition to a balanced fertilizer, consider supplementing with micronutrients like iron, magnesium, and calcium if your soil is deficient in these elements. Soil testing can help determine any nutrient deficiencies and guide your fertilizer choices.

Organic Options: If you prefer organic gardening practices, there are organic fertilizers available specifically formulated for roses. These products contain natural ingredients and beneficial microorganisms that promote soil health and plant vitality.

Mulching: Applying a layer of organic mulch around the base of your Double Knock Out Roses can help retain moisture, regulate soil temperature, and gradually release nutrients as it decomposes. This can complement the effects of fertilizer and improve overall soil fertility.

By providing the right fertilizer and nutrients, you can support the growth, health, and abundant flowering of your Double Knock Out Roses, ensuring they thrive and dazzle with their vibrant blooms throughout the growing season.

The Double Knock Out Rose tree is celebrated for several exceptional qualities:

Abundant Blooms: It produces an abundance of vibrant, double-petaled blooms throughout the growing season, providing long-lasting color and beauty to gardens and landscapes.

Continuous Blooming: Unlike traditional roses that bloom once or twice a year, the Double Knock Out Rose tree blooms continuously from spring to frost, ensuring a stunning display of flowers for months on end.

Low Maintenance: Known for its disease resistance and adaptability, this rose tree requires minimal maintenance compared to other rose varieties. It is highly tolerant of heat, humidity, and various soil conditions.

Versatility: Double Knock Out Rose trees can be grown as standalone specimens, hedges, or incorporated into mixed borders. They are also suitable for container gardening, making them versatile choices for landscaping projects of all sizes.

Longevity: With proper care, Double Knock Out Rose trees can live for many years, providing reliable beauty and enjoyment season after season.

Attracts Pollinators: The abundant blooms of Double Knock Out Rose trees attract pollinators such as bees and butterflies, contributing to a healthy garden ecosystem.

Overall, the Double Knock Out Rose tree is prized for its stunning blooms, ease of care, and versatility, making it a popular choice among gardeners and landscapers alike.

Watering requirements for Double Knock Out Rose trees can vary depending on factors such as climate, soil type, and rainfall. However, as a general guideline:

Established Trees: Once established, Double Knock Out Rose trees are moderately drought-tolerant. Water deeply once or twice a week during dry periods, providing enough water to moisten the soil to the root depth.

Newly Planted Trees: For the first few weeks after planting, water more frequently to help the roots establish. Water deeply immediately after planting and then every 2-3 days, adjusting based on weather conditions.

Summer Months: Increase watering frequency during hot summer months, especially if there's limited rainfall. Water early in the morning or late in the afternoon to minimize evaporation.

Container-Grown Trees: Container-grown Double Knock Out Rose trees may require more frequent watering, as containers can dry out faster than the ground. Check the soil moisture regularly and water when the top inch of soil feels dry.

Avoid Overwatering: While Double Knock Out Rose trees appreciate consistent moisture, they are susceptible to root rot if the soil remains waterlogged. Ensure proper drainage to prevent water from pooling around the roots.

Always monitor the soil moisture and adjust your watering schedule accordingly, taking into account weather conditions and the specific needs of your Double Knock Out Rose tree.

More Details

We process and ship your order as quickly as possible, typically within 1-3 business days. You will receive a shipping confirmation with tracking information once your item(s) ship.

We have perfected packaging and shipping plants & trees! That is why we DO NOT use any third-party fulfillment like most other online retailers. Your trees go straight from our farm to your door, safely packaged by our team of seasoned professionals. Our process ensures your plants leave our facility and arrive to your door in the best condition possible!

In cases of extreme cold or hot weather, we may temporarily delay shipping to ensure the well-being of your plants. Our primary focus is on delivering healthy and thriving plants to you. Rest assured, we'll make every effort to notify you of any delays promptly.

Please allow additional ship times during inclement weather and sale periods. We do not process or ship orders on the weekend or U.S. Holidays. Simply Trees is not responsible for delays due to carriers, local disruptions, or weather.

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Learn more about our Shipping Policy

At Simply Trees, we're committed to your satisfaction. If your plants arrive considerably damaged or sustained damage beyond the point of recovery, please contact us within five days at sales@simplytrees.com with clear photos of the entire plant in question for assistance. Our 30-day guarantee covers issues after planting, subject to our terms and conditions. We can't cover plants in the wrong climate or with inadequate care, but we're here to help in other situations. For a detailed understanding of our 30-day guarantee and how we ensure a fair process, click here to learn more.

What's inside?

Your order from Simply Trees is more than just a box of plants—it’s a carefully curated experience. Here’s what’s inside:

  • We hand-select our plants for premium-quality from top growers nationwide
  • Each plant is then cleaned, prepped, and pruned to remove any blemishes and encourage new growth
  • Expertly treated and inspected for preventative measure
  • The pot is wrapped in a durable plastic bag and secured with a zip tie; house plants get extra protection with a recyclable nursery bag
  • Your plant is strapped into our durable double-pane boxes, secured in place with a heavy-duty zip tie to ensure safe transit
  • A thank you card with a QR code leads to our guide on welcoming your new plants home

We take pride in making sure every detail is just right, so you can enjoy your new greenery from the moment it arrives.

Sustainable shipping, quality care

We've perfected the art of packaging and shipping plants and trees! Unlike most online retailers, we handle everything in-house—no third-party fulfillment. Our experienced team carefully packages your plants to ensure they arrive from our farm to your door in perfect condition.