Knock Out roses are supposed to be one of the hardiest, and disease resistent roses available at the moment. In order to keep them disease resistent you want to plant them in an environment that’s conducive to their health and vigour. Follow these steps when planting Knockout roses and they should reward you with disease free growth and prolific blooms.
Planting Knockout Roses - do this before planting
Make sure you plant your Knockout roses in a position that gets at least 5-6 hours of sun each day. If they don’t get enough sun they start getting sparse foliage and become more prone to rose diseases.
Check the pH of the soil; all roses, including Knockout roses like a soil pH of about 6.5. There are simple to use pH testing kits available from your local nursery or garden centre stores.
Check the drainange – I can’t stress this enough – bad drainage is one of the main reasons newly planted roses can droop and die (other reasons they can droop and eventually die are not watering enough; applying fertilizer to newly planted roses, esp bare-root roses; and overdoing the fertilizer when it’s time to fertilize (usually a month or so after planting).
So make sure the soil drains freely after a good soaking. Like any roses, Knock Out Roses hate wet feet. Rose roots left in waterlogged soil end up rotting. The fine root hairs that carry water to the rose plant rot and disintegrate, so even though the soil is wet, the roses roots can’t uptake that water to the rest of the plant.
After making sure the soil drains freely, add some well composted and milled cow manure or rose planting compost to the soil. Avoid fresh manures or rose food at planting time so you don’t burn any newly forming fine root hairs.
When planting bare-root knock out roses it’s a good idea to soak them for an hour before planting in a bucket of water that’s got some liquid seaweed mixed in at half strength (make sure it’s only at half the recommended dosage rate). While they’re soaking, dig out a hole large enough for the roots to spread across and deep enough for the bud union to sit just above soil level if planting in warm climate zones or just under soil level if planting in cold zones that have harsh winters.
How To Plant Knock Out Roses
When you’re ready to plant the bare root Knock Out rose, make a small mound at the bottom of the hole and sit the rose on that and spread the roots out without any kinks in them. then its just a matter of backfilling the soil and firming it down well but gently as you go. You don’t want to compact the soil too tightly so there’s no tiny particles for soil air but you don’t want to backfill too loosely either and have too many air pockets around the rose roots.
If you’re planting a potted knockout rose, just dig a hole double the width of the pot and at the same depth as the pot so that once planted, the rose sits at the same soil level it did whilst in the pot. Again though, if you live in a cold climate zone where it’s recommended to plant your roses with the bud union just under the soil surface, then make the planting hole a little deeper (say 3-5 inches) for the potted rose so the bud union sits just under soil level.
Remove the rose from the pot and gently tease out some of the fine feeder roots, then place in the hole and backfill as above.
Give the rose a good watering, then fill up a watering can and add liquid seaweed like Maxicrop Liquid Seaweedat half the recommended dilution rate and water that in. Liquid seaweed will help your knockout rose cope with the shock of being placed in a new environment and get it off to a good start. I never plant anything without doing this, but it’s important to water the plant in well first with just plain water, then use the half strength liquid seaweed.
I can’t stress how important it is to keep the water up to your newly planted roses for the first few months while they are establishing. Older, established roses can tolerate dry spells, but a newly planted rose needs plenty of water while it is establishing. If in doubt about whether it needs watering, stick your finger into the soil to check the first few inches. If it’s dry an inch or more down, it’s time to water.
And give it a long deep soak, not a quick spray. Long deep soaking helps the roots to grow deep. Shallow watering causes roots to grow close to the surface and in hot weather, esp if not mulched, the roses are more prone to moisture stress.
After watering your knockout rose in, you can cover the soil with some mulch. Spread it about 2 inches thick to help retain moisture in the soil, and suppress weeds. Be sure not to put the mulch too close to the stem.
If the weather is still cool where you’re planting, don’t worry about putting the mulch around your rose until it gets warmer, so the soil has a chance to warm up. If you plant your knockout rose when the weather is quite hot, then put the mulch over the soil to keep moisture in, weeds out and the soil temperature cooler in the heat.
Please don’t fertilize your newly planted knock out roses until a month after planting, especially bare-root roses. The fine feeder roots are trying to establish and if you fertilize the roses, it will cause the tiny hairs on the newly forming feeder roots to burn and die and then there will be nothing to uptake water and nutrients to your plant.
This is the typical scenario of fertilizing at planting time or over-fertlizing when it’s time to fertilize; the plant droops or wilts after a short period of time because it can’t uptake the soil water because feeder hairs on the roots have burned, folks keep watering and feeding the rose wondering why the plant is still continuing to droop and not perk up, and its because there’s no root hairs on the roots to uptake the water and nutrients in the soil water, so the rose is just sitting there slowly dying from lack of water and nutrients even though there’s plenty of both in the soil.
That’s why it’s important to wait until the new buds have formed into shoots and the leaves on those shoots are leafing out to full size before you fertilize.
These steps on planting knockout roses should get them off to a flying start, and keep them growing vigourously and disease free for years to come.