I love writing about subjects I'm passionate about, especially gardening, and have been growing Knockout roses around my home for years.
So you've planted Knockout roses, and they have started displaying their beautiful blooms. Now, you wonder how to keep your roses blooming all the way through fall. It's pretty easy to do. This guide will show you how.
What Makes Knockouts Different From Other Roses?
Knockouts are hardy shrub roses that grow about 3 feet high. In warmer climates, they can grow larger. There are many varieties and colors, including red, pink, rainbow, and double Knockout roses.
Knockout roses are a true success story in the botanical world. They are very hardy perennial plants and can withstand very difficult conditions—the kinds of conditions that would severely stifle (or kill) most other roses. Besides being hardy in drought conditions, they also survive cold and hot weather very well and are much more resistant to diseases and pests than other types of roses.
All that being said, there are ways to keep your Knockout roses blooming from spring all the way up until the first hard frost of fall. While these roses normally bloom on their own, you can help the process along with a few simple steps. This can result in more blooms and more frequent flowering.
How to Keep Knockout Roses Blooming Longer
Although Knockouts are very hardy and resilient plants, there are still a few good practices you can use to help ensure that they stay healthy and bloom to their fullest extent.
Keep Your Bushes Well Watered and Well Drained
Though they are drought resistant, regular watering will produce more blooms if the season is dry. Water at the bottom to avoid promoting diseases. Even though Knockout roses are disease resistant, it is still better to take these steps. Help keep the moisture in the ground by lightly mulching around the base of the rose bush, leaving about an inch gap near the main trunk to avoid mildew or disease. On the flip side, don't overwater your roses. They must be in well-drained soil to prevent possible rot.
Find a Good, Rose-Specific Fertilizer
Of course, adding fertilizer will help keep your Knockout roses blooming regularly. Find one formulated specifically for roses. Water the soil well to protect the roots before adding the rose fertilizer. Start fertilizing them after the first flowering cycle is over. Continue to fertilize according to the package instructions until the end of the summer season.
Spray Some Neem Oil to Keep Pests Away
If aphids are a problem with your roses, try neem oil spray. It is a natural way to get rid of pests without using harmful chemicals.
Knockouts Deadhead Themselves
Another great thing about Knockout rose bushes is that they were developed to deadhead themselves. What this means is that whenever a bloom dies, the bush will drop off the withered bloom in order to replace it with a new one. They will bloom about every six weeks or so until late fall. Many other rose species must be deadheaded manually, or the rose will stop blooming for the season.
Prune the Bushes in Early Spring
Another way to keep Knockout roses blooming each year is to prune them back each spring, early in the season. This will produce new growth and blooms.
How I Came to Discover (and Love) Knockout Roses
I have a bit of history with roses and all of their problems. Or rather, my husband does. We bought an old house that used to have a rose garden on the south side. Only a couple of the rose bushes survived.
My husband set to reviving them and adding new roses. It was an exercise in futility. We live in the humid South. The poor roses and my poor husband kept fighting, but it was a losing battle. He would get rid of one problem and another would pop up. You name it, our roses got it: mold, fungus, aphids, Japanese beetles, black spot, powdery mildew—the works.
I explained to him that the previous owners no doubt had a professional gardener that worked on the rose garden full time. He still was not deterred. As a matter of fact, my husband didn't give up on the roses until he took a job that required travel almost all year long.
That was when I decided to plant Knockout rose bushes.
Where Should You Plant Knockout Roses?
If you haven't planted your Knockout rose bushes yet, they do best in sunny locations, just like other roses. Most roses require pretty much full sun to do well at all. Knockout roses can get by on partly shady conditions, but they do best in sun. Try to plant them in well-drained soil. This is one of the most important requirements for healthy rose bushes.
Add compost or manure to the soil before planting, if possible. You can also add rose fertilizer formulated just for this purpose.
Vicki on July 20, 2020:
Today is July 20 2020 my neighbor purchased me a knock out rose from Home Depot. Lower leaves are missing top is blooming. That means it has been in a pot since March. Do I prune at all or leave it. Just plant and water help
Nicholas Cirilli on July 04, 2020:
Hello my wife and i hired a pro landscaper to plant 3 knock out rose bushes however once they were planted they were in full bloom . Now roses have dried out and died they get watered 2 times per day for 17 mins with a mister sprinkler installed on each bush. I dont know if i should cut out old dead roses please advise thanks.
Joe Mack on June 30, 2020:
The deer have eaten all my knockout rose flowers and buds. It’s July now. Will they reboot. I’m going to put netting around them now. Hope it works.
Than you for your kind advice,
Laurie Annie on September 28, 2011:
My knock roses have black spots and it looks like something is eating them rather aggressively. I am going to cut them back and treat them. Have you heard of epson salt sprinkled in the soil. Is it ok for me to prune them know? Any words of wisdom shared would be greatly appreciated!
Mini Greenhouse on April 13, 2011:
My gran used to prune her roses so aggressively it used to bother me, thinking that it would never recover. Then later in the year they'd be a huge bloom of colour and she'd say 'told you so' haha. Great hub here, thank you for the info
Jim and Laura from Chicago area on July 25, 2010:
Very informative hub! I love Knock Out Roses and recommend them to anyone looking for an easy care, low maintenance rose.
Emily on July 05, 2010:
Last Friday we just planted 12 knock-out roses around our fountain and got up Monday morning to find all the beautiful blooms missing!!! Did deer eat them?
samiaali on May 20, 2010:
Thanks for a very informative article. I just purchased several Knockout Rose plants. I planted 2 of them and will plant the others this weekend. I can't wait. You have given me some useful tips. Thanks!
GiftedGrandma from USA on May 19, 2010:
They are quite popular in my neighborhood. Thanks for the information.
prasetio30 from malang-indonesia on May 11, 2010:
good tips for beautiful flower. I liked it very much!
Holle Abee from Georgia on May 06, 2010:
I used to grow roses. I need to plant more. Great tips!
Hello, hello, from London, UK on May 06, 2010:
Thank you for a wonderful help.
Katie McMurray from Ohio on May 05, 2010:
Thanks for the helpful how to keep knockout roses blooming through-fall. I have some roses that will benefit from this. Thanks and Peace :)
Sandy Mertens from Wisconsin, USA on May 05, 2010:
Thanks for the information. We love to plant roses.
Angela Harris (author) from Around the USA on May 05, 2010:
Thanks for the compliment! I love knockout roses, too. They are my lazy gardener's dream! ;-)
Debra Allen from West By God on May 05, 2010:
Thank You for this informative hub! I have a couple of them and love them.