The Complete Guide to Knock Out® Roses
The Knock Out Rose is the solution to all the rose-lover’s problems. Unlike other delicate varieties, the Knock Out is one of the toughest plants in the garden. It’s winter hardy (from Florida all the way to Canada). It self-cleans spent blooms. It can even handle drought and resists Black Spot. In fact, it’s resistant to pretty much any disease or pest.
Best of all: the Knock Out has at least 4 cycles of blooms each season, compared to just 3 bloom cycles of other roses.
This miracle of the garden world grows with vigor, displaying a blanket of bouquets that spreads four feet at maturity. You can choose from numerous colors: reds, pinks, yellows, or whites. Flower gluttons can even pick out the Double Knock Out® Rose with double the flowers of the original. You can even have your own Knock Out® Rose Tree!
The Knock Out® Rose Varieties and Colors
There are several different varieties and forms of the Knock Out Rose. Here’s a timeline of their introductions:
2000 – The Original Knock Out® Red Rose is introduced to an unsuspecting public. Winner of the All America Rose Selection Award.
2004 – Blushing Knock Out® introduced: Pale pink petals.
2004 – Pink Knock Out®: Deep pink petals.
2005 – Double Knock Out® : Red bloomer with double the petals of the original
2006 – Sunny Knock Out®: Light petals with a deep yellow center. The only fragrant Knock Out Rose.
2007 – Rainbow Knock Out®: Pink petals with a yellow center. Winner of the All America Rose Selection Award.
2010 – Knock Out® Rose Tree: The same hardiness and bloom characteristics of the Knock Outs, but in a standard tree form. Great for patios.
Picking the Perfect Knock Out® Rose
And while the Knock Outs all exhibit the same hearty characteristics, take time to consider what style of growing Knock Outs is best for you.
● Bareroot vs. potted
● Container vs. ground
● Do you want variety of color?
● Do you want shrub or tree?
● Is fragrance important?
For the budget minded, the bareroot is cheapest, but also takes the longest time to establish in your landscape. Compared to the potted Knock Outs that already have the celebrity rose looks, the bareroot is, well, bare. Buying a potted plant gives you that instant satisfaction. You become immediately acquainted with the Knock Out’s looks, and it’s ready to plant.
Knockout Roses are highly adaptable, and they can live happily in the ground or in a container. It’s up to you to consider what is best for your space. If you have a limited amount of growing space (mature Knock Outs shrubs grow out to four feet wide and high in the ground), consider the benefits of the container:
● Great for sprucing up a bare patio or walkway.
● Can be moved around to more desirable locations.
The Knock Out Rose Tree can also live a comfy life in a container thanks to its dwarf tree characteristics. It reaches a manageable height of 7 feet and only spreads out about 3 feet!
If you have the space in the ground, the Knock Out will add a colorful punch to your garden designs. And if you live in growing zones 5-9, you can rest assured that the Knock Out will brave the winter with ease. Thanks to its spread, consider getting a group of three or five shrubs to cover a bare spot or add a flourish of color along the driveway. And thanks to blooms that last from early spring until the last days of fall, you’ll have a garden space covered in petals of every color imaginable. The Knockout Rose Trees also sits pretty in almost any landscape feature.
You should also take color into consideration when planning your spring garden. Do you want the traditional red looks of the original Knock Out Rose, or do you prefer the Pink Knock Out? You can also go out of the mainstream with the canary yellows of the Sunny Knock Out. Plus, the Sunny is the only member of this prestigious family to have a fragrance. Also, you can always mix and match colors for a rainbow of blooms in the backyard. You can even snip some flowers to make an incredible bouquet for every room in the house.
How to Plant the Knock Out® Rose
Now comes the fun part. You get to spend some time outdoors, and it’s up to you to create a design that works for your new Knock Out Roses. Plus, they are easy to plant and fertilizing is a cinch.
Your main task is planning. Pick an area where you have at least four to eight hours of sunshine. Make sure to space the plants between 20-30 inches for…
● Optimal hedge appeal
● Disease prevention
Next, determine what kind of soil you are working with. A well-draining loamy soil is preferable, but not everyone is so lucky. If you’re dealing with lots of clay, don’t fret. You can break up the clay with green sand fertilizer. This potassium powerhouse enriches the soil and keeps clay from bunching up your plant’s roots. Also, an addition of good compost in the soil creates a nutrient rich environment that not even clay can ruin.
Also, try to plant your roses in the evening or on an overcast day. Planting Knock Outs when the sun is in full force can inhibit your plant’s growth.
● Wheelbarrow (for dirt)
● Gardening gloves
● Tape measure (to space plants)
For each hole, make sure to dig six inches wider and deeper than the root ball. Set aside the dirt in your wheelbarrow, but a small amount back in the hole. Grab your tape measure and distance each hole. Go ahead and dig all the holes to allow the roses to have more time to sit in the seaweed solution.
Now it’s time to show the Knock Outs their new home. Carefully place each plant into their respective holes and gingerly spread the roots out. Add the rest of the dirt and tamp down the soil lightly to give your roses some breathing room.
Now, if you live in a warm climate (Growing Zones 9 and higher), leave your roots just above the soil level. But, if you have frequent cold spells, place the roots just under the soil level. Water the soil well and keep it moist (but not saturated) for the first several months until the plants establish. A great way to check the soil’s moisture is to dip your finger in the dirt. If it’s more than an inch dry at the top, it’s watering time.
Don’t feed your Knock Out Roses with a full strength organic rose fertilizer for at least the first month after planting. Once they establish, you can apply a granular feed (like a 6-6-4) several times in the growing season. Also for a more aesthetic look, you can add nice layer of mulch around the roses. Plus, it keeps your beds weed free.
Pruning Your Knock Out® Roses
Don’t worry, pruning is quite easy. Your blooms will thank you.
You've probably heard the nightmarish scenarios of rose pruning. Unforgiving thorns destroying hands. Bad cuts killing a prized rose bush. It’s enough to make any beginner’s pruning hands shaky.
Luckily, the Knock Outs can typically withstand even the most errant pruning. Plus, if you just planted your bushes, it’s a good chance you won’t have to start cutting for one to two years.
Spring time is the best cutting time. If you see the rose buds swelling, but the plant is lacking new growth, then it’s time to prune.
Dip your shears in rubbing alcohol (or bleach) to ensure they are free of disease. Cuts should be done at a 45 degree angle.
Now determine how big you want your bush to be and apply what is called the “two foot rule”. This means that whatever size you cut the rose back to, it will grow back two feet in the season. For example, if you want your Knock Outs to be their full size in the middle of the growing season (four feet high and wide), cut your bush down to two feet in the spring.
Cut all healthy shoots back by no more than half. Cut out any interior growth and take out any canes (the spindly branches) that are overlapping with healthy branches. The added benefit of cutting your roses back is that the plant will stop focusing all its energy on foliage and spend more time focusing on bloom production.
As summer hits, you must rid the roses of the “Three D’s”: dead, diseased and damaged wood. Also, consider if you want to deadhead your Knock Outs. One of their main attributes (and what makes them unique from other roses) is that they “self-clean” by dropping old blooms. However, you can give your bushes an elegant appeal by cutting off flowers earlier. If you decide to go this route, cut old flowers just above the five-leaflet leaf found under the flower. This is also a great time to trim up new growth and canes. Just don’t go wild with the pruners. A blazing sun can wreak havoc on an over-pruned rose bush.
You don’t have to prune in the autumn since your bush is slowing down and preparing for dormancy. But if you’re just itching for one more trim before winter, prune the plant up to one-third but no more. Make sure to fertilize one more time before the onset of cold. And, mulch heavily (up to four inches) to give your Knock Out Roses’ roots a strong winter coat.
The Knock Out Rose was born in a basement. Its father is William Radler, a rose breeder from Milwaukee whose obsession for the flowers began at age 9, when Radler bought his first rose for 49 cents at the local A&P. The plant thrived the next summer, and Radler’s addiction grew. He chaired his first rose show at 19. While earning a landscape architecture degree, he worked as the director of a botanic garden to fuel his obsession with breeding roses.
Radler worked hard to breed a rose that not only had elegant looks, but also be resistant to the diseases that made growing roses so difficult. He wanted a shrub-like specimen with little need for pampering. In 1989, he germinated his first Knock Out seed in his small basement.
For 11 years, Radler toiled on how to create the perfect rose through bud grafting and even introducing disease pathogens in his basement. Radler would dry and grind black-spot infected leaves into a powder and sprinkle them on young plants. Any roses that contracted the disease were taken out. The disease-resistant plants were grown to maturity and became the breeding stock.
In 1997, Radler introduced his perfected rose to the All America Rose Selections committee. His Knock Out was declared the overall winner. 3 years later, 250,000 Knock Out Roses were released to the public. The mania reached Beatle hysteria proportions, and the Knock Out is about to surpass the 100 million sold mark.