Knock out roses are gaining popularity because they are easy to care for and fairly disease resistant. One of their selling points is that they are “self cleaning” meaning the petals fall clean, and while that may be true this article discusses why you should regularly deadhead them and explains the simple process of pruning Knock Out roses annually.
Deadheading Knock Out Roses.
During the growing season it’s worth your time getting rid of any spent flowers by deadheading the rose bush. Deadheading on a regular basis will help the plant maintain its compact bushy habit and encourage prolific flowering. It is promoted as “self cleaning”, however, lightly pruning knock out roses is beneficial to the plant. If you don’t remove the spent flowers, they will develop into rose hips and the energy the rose uses in forming these hips greatly reduces flower production.
If you like the look of the orange coloured hips on the rose as some do, then just realise that you wont get masses of flowers on your knock out rose. When deadheading you just cut the spent flowerhead back a couple of inches – nothing too severe during the growing season as the flowers bloom on new wood. This encourages new growth and an abundance of new flowers. You also want to trim any wayward branches to help keep its shape.
When to Prune Knockout Roses
Knockout roses benefit from an annual prune. For those living in a warmer climate zone, for example in zones 7+, you’ll want to prune knock out roses in mid to late Winter. For those living in colder climate zones, early to mid Spring once the frosts are over, is more ideal. Though you are always better off asking a local plant nursery, local garden club or rose society the ideal rose pruning time for your particular location, so you get the timing spot on.
Pruning Knockout Roses
Because the knock out rose is a landscape shrub rose, it doesn’t need the detailed pruning that some other species need. Remove any dead or damaged wood and if there is a lot of overcrowding of branches in the centre of the rose you can remove a few of these branches if you wish, to open the rose plant up a little and improve air circulation. This is not necessary however, and some people are happy to leave them as is. It won’t hurt the plant if you don’t.
Knockout Roses Pruning
You can easily prune knock out roses annually by reducing their height by half to two thirds. This way you will end up with a knockout rose that is around 12-18 inches high after pruning. You don’t need to fuss with each stem individually, cutting to an outward facing bud either; you can use hedge trimmers or loppers to prune the knock out roses down to size.
Some folk don’t prune down to 12 inches as they prefer to have taller knockout rose bushes so it’s up to you. You can afford to experiment a little with this plant so one year you might prune it 12 inches and see what height you end up with at the end of the growing season; the next annual prune, you could prune a little higher; 18 inches or more, and see how tall they grow from that pruning height.
There’s no hard and fast rule with this easycare rose, though knockout roses do benefit from an annual prune. After experimenting, you can just decide on the pruning height you prefer.
Every couple of years remove some of the older woodier branches at the base of the plant to encourage the development of new branches which will produce much better blooms. Doing this will keep your knock out rose blooming for many years. Pruning Knockout roses is an easy garden task and one more reason this rose is so popular with gardeners.