Knockout Rose Bushes

I have 1/2 doz or so but no expert. I follow LSU AgCenter general recommendations/suggestions. By Labor Day, at the latest, cut back by 1/3, fertilize. By Valentines Day, cut back by 2/3rds, or maybe 18 inches above ground, remove any large, dead canes, fertllize. May or so, another fertilization.

Yes, I think you are watering too frequently. In the absence of at least 1 inch + rain, one good watering soaking per week, equivalent to a 1 inch + rain.

These are direct quotes from an article by Dan Gill, retired consumer horticulturist LSU AgCenter, on knockouts. Sorry I can’t provide a link as this article isn’t posted on-line.

“The first pruning is done in late January (south Louisiana) through early to mid-February (Valentine’s Day is commonly used as the time to prune in north Louisiana). Pruning later will delay the outstanding spring and summer flowering. There is no set way to prune a Knock Out rose (or other landscape roses). It depends entirely on the desires of the gardener and the situation.”

“ Fertilize the bushes in March with any general purpose fertilizer or a fertilizer labeled for roses following label directions.”

“ Another opportunity to cut the bushes back arrives in late August (north Louisiana) through early September (south Louisiana). Again, you don’t have to be too fussy about this. This pruning is not as severe as the late winter pruning. Plants are generally cut back by about one-third their height, more or less, depending on how much control is needed. Don’t forget to remove anything dead when you cut the bushes back. Fertilize the bushes after this pruning with any general purpose fertilizer or fertilizer labeled for roses following label directions.”

“A Note on Watering:

Knock Out roses (and landscape roses in general) are very drought tolerant. After their first year in the ground when they are getting established, Knock Out roses rarely need supplemental irrigation. Gardeners plant these roses because of their lower maintenance requirements, and then often proceed to pamper them to death.

Generally, established Knock Out roses can get along quite well on natural rainfall with little supplemental irrigation. Resist the temptation to water them when they look perfectly fine just because the weather is dry. Wait for the foliage to wilt slightly before watering deeply and thoroughly. And, then don’t water again until the plants let you know they are thirsty.

A leading cause of Knock Out rose bushes dying is due to over irrigation that leads to fungal root infections (or planting in poorly drained beds). This is entirely avoidable. These are low maintenance plants – treat them that way.”

To properly trim them back you first take out any interior growing stems to open it up for better air circulation.

Then take out the growth that starts on the outside and grows toward the middle. Also any dead branches.

I cut mine back pretty severely twice a year, once around February and again around August. They look like shite for a few weeks until new growth appears, but then they take off and the blooms are plentiful off the new growth.

I also use Miracle Grow blue crystals and put that in a watering can to water around the base of the bush 5-6 times a year.

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I cut mine back severely every other year. They come back fuller and create more blooms. Full sun, very little water on mine.

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This, but I am on my second planting of them. First ones lasted about 10 years, but got to the point they were just tired and not producing roses.

Second ones, really not happy with them after the third year. Got those up in Forest Hill as the first. Most likely will rip them out in the fall and go with something new.

Mine are 5 years old and probably 6-8 foot wide. I definitely missed a pruning or 2 and they are growing strong.

I cut mine back hard a couple of times a year and they come back fine every time