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clcscaper
11-13-2008, 06:33 PM
I installed a few knockout roses for a customer around midsummer and they started out great but lost most of their leaves, quit blooming and growing before cold weather came. I thought these were supposed to be very hardy and need little care. I checked them for visible pests and found none. should this be expected in their first year or do you think there is a problem?

White Gardens
11-14-2008, 01:13 AM
I installed a few knockout roses for a customer around midsummer and they started out great but lost most of their leaves, quit blooming and growing before cold weather came. I thought these were supposed to be very hardy and need little care. I checked them for visible pests and found none. should this be expected in their first year or do you think there is a problem?

Was watering an issue???

Could have been a disease that the roses weren't resistant too. Regardless of hardiness, something might nail them.

A lot of Knockouts I've dealt with don't seem to like the stresses of the late summer heat etc, and have looked a little wilted or even drop a few leaves, but never all of them. Some damage was from JB.

Did the leaves ever exhibit any spots or discoloration before the wilted??

I really don't like knock outs, I'm a traditionalist when it comes to roses, and I never liked the form of knock-outs.

Dreams To Designs
11-14-2008, 10:11 AM
Knockouts are extremely hardy, but do need some care to get established. Did they receive enough water? Which variety of Knockout did you use. There are Knockouts, Double Knockouts (Red), Pink & Double Pink, Rainbow, Blushing and Sunny. The Rainbow seems to be the most troublesome, especially in nursery conditions, but once established they will flourish.

If all of them dropped all of their leaves, that would likely be transplant shock and likely from a watering issue. They are pest and disease resistant, but not immune.

Kirk

clcscaper
11-14-2008, 03:23 PM
I don't think watering was an issue. As a matter of fact I thought the owners might have been overwatering after about a month so I ask them to back off to just a couple times a week. The problem started after about a month. First they stopped producing blooms them they started to loose leaves. I looked at them when the problem started and they didn't look to have any mildew on the leaves or worms. I have had problems before with worms getting on knockouts but I could see them. These particular ones are double reds. I didn't put any fertilizer on them considering it was summer so I'm not sure what the problem is. I was expecting them to just about double their size by the end of growing season but they look pitiful now. They don't get full sun but they get several hours of midday sun. Any more ideas?

Spartan Pride
11-14-2008, 04:59 PM
Over watering could definitely be a problem. Most roses do very poorly if over watered or planted in poorly drained soil.

On another thought, are there any other plantings near the roses? If you are having a soil issue, maybe some other newly planted beds are struggling?

clcscaper
11-14-2008, 06:16 PM
The only other plantings close by are some daylillies that I planted on the border of the same bed. They didn't neccesarily flourish but they did OK, continued to bloom off and on through the season. I mixed in some topsoil with the dirt when I planted to help with drainage.

Dreams To Designs
11-17-2008, 11:29 AM
Double Knockouts are reliably tough. Are there leaf or flower buds emerging now? What is the soil composition?

Use a soil probe and check near the roots for how well or over watered the soil is. Typically when folks see wilt or leaves dropping, they water more. Rather than mix topsoil into your backfill, try compost, gravel and maybe a plant starter, like Espoma Bio-Tone. The amount of sun will definitely affect growth and flowering, but not to the devastation you are experiencing.

Depending on the root system of what you planted, roses will often restructure their roots to become established before pushing top growth or flowers. Sounds like your situation has become severe, so removal and inspection of at least one plant would be in order. I still have Knockouts blooming here in containers and in the ground. That may change this week with highs expected in the 30's. Time for the long pants.

Kirk

White Gardens
11-17-2008, 10:13 PM
Double Knockouts are reliably tough. Are there leaf or flower buds emerging now? What is the soil composition?

Use a soil probe and check near the roots for how well or over watered the soil is. Typically when folks see wilt or leaves dropping, they water more. Rather than mix topsoil into your backfill, try compost, gravel and maybe a plant starter, like Espoma Bio-Tone. The amount of sun will definitely affect growth and flowering, but not to the devastation you are experiencing.

Depending on the root system of what you planted, roses will often restructure their roots to become established before pushing top growth or flowers. Sounds like your situation has become severe, so removal and inspection of at least one plant would be in order. I still have Knockouts blooming here in containers and in the ground. That may change this week with highs expected in the 30's. Time for the long pants.

Kirk


Ditto, and the only other thing I could think of is to do a soil sample. That is one of the simplist and the first point I usually look when trying to find the root of problems.

PHS
11-18-2008, 09:06 PM
clc, Lots of good advice so far. Also keep your eyes open for chilli Thrips. They came into Florida a few years back. Last year here I only had two properties with infested Roses. This year they're everywhere. Probably half the Knockouts I've seen around town this year are totally wrecked by them.

Smallaxe
11-20-2008, 08:50 AM
clc,
There is a lot of "Should be..." , or "If anything...", or "I did this..." - in your responses.

You needed to have investigated the soil several days after soaking them in. Too many scapers do not know how to water in a plant and treat the soil bed thereafter as though it does not exist. Non of these things can be guessed at.

Scratch around in the dirt and know what is going on with a plants roots. :)

KACYDS
11-20-2008, 03:31 PM
clc, Lots of good advice so far. Also keep your eyes open for chilli Thrips. They came into Florida a few years back. Last year here I only had two properties with infested Roses. This year they're everywhere. Probably half the Knockouts I've seen around town this year are totally wrecked by them.

Chilli Thrips? Never heard of them before. Where they easy to kill? What did you use? Keep them in Lafayette, dont send them to New Orleans. Have enough problems already. lol:laugh::laugh:

Learn something everyday........

Lawnworks
11-20-2008, 06:43 PM
When is the best time to prune knockouts? One of my neighbors, pruned her knockouts SEVERLY a month ago... I mean these were 4' tall knockouts about 3 years old, and they pruned them about 1.5' off of the ground leaving no foilage. I was amazed to see new growth a couple weeks ago. When I pruned mine that severely, it died!

White Gardens
11-20-2008, 07:00 PM
All roses are recommended to be cut back in the spring after they have began to bud out for the season.

Fall cut backs aren't recommended, and that's kinda an old school method that is out-dated. Also, the only protection they need for the winter is a mound of mulch around the base to help protect the roots over the winter, and that's only for delicate antique varieties.

Styrofoam cones and cages filled with leaves around the roses are a no-no.

Lawnworks
11-20-2008, 07:16 PM
How severly have you cut knockouts back? I am scared to prune them to where there is no foilage.

White Gardens
11-20-2008, 07:59 PM
My rule of thumb is if it's more than 1/4 inch in diameter in size (stem), then I leave it alone, unless I have Elmer's glue with me.

If the stem is bigger than 1/4 inch, then it is recommended to put Elmer's white glue on the cut to seal it from infection.

I always leave at least 12 inches of height when I cut roses back. After they have started to bud and fill out, I go back in and trim them to shape and take out any canes that are going the wrong direction.

Cut angles, and distance to the next bud are also critical.

Some roses I can cut back and not think twice about, and some I meticulously cut and clean my pruners with a light bleach solution after each plant is done so I don't transfer disease.

I've seen some people cut their roses clear to the ground, but I don't unless I see new canes forming just above ground and I know for sure I'm going to get new growth.

Lawnworks
11-20-2008, 09:27 PM
With these red knockouts... I guess it is a crapshoot b/c they are not exactly a compact growing specimen. It seems to cut it down to 1.5', there will be no foilage... that is kind of why I am scared to prune so low. Elmer's glue... great suggestion.

White Gardens
11-21-2008, 01:14 AM
With these red knockouts... I guess it is a crapshoot b/c they are not exactly a compact growing specimen. It seems to cut it down to 1.5', there will be no foilage... that is kind of why I am scared to prune so low. Elmer's glue... great suggestion.


Crapshoot, I like that.

The one thing I don't like about knockouts is that they don't seem to push up too many new canes every year compared to most traditional varieties. It seems like they just want to keep the same apical stem for their life cycle.

Just go easy on them when pruning. Just like with any rose, wait until early summer to give them a detailed pruning, by that point you should be able to tell the health of the plant and how well it's growing. All in experience.

When I prune all my roses for customers in the spring, usually I cut off most if not all the sprouting leaves. I only do this if I can tell for sure that there seems to be a good bud (red in color) on the canes to let me know that they will shoot out. The only real problem I've had with this is that I trimmed 15 rose bushes for a customer one spring and we had a really late freeze that killed back all the exposed canes. Luckily the roses were old enough and healthy enough that they snapped out of it no problems, they just started out much shorter than I like.

Good luck, do some research on-line to see what other Knock-out enthusiasts do for pruning.

PHS
11-21-2008, 09:39 AM
Kris, PM me your email address and I'll send you some info on them. They were giving me problems on a few different plants, Knockouts, antique and climbing roses, Nandina, Plumbago, and Impatiens.

I tried a variety of different materials that seemed to work ok but the bigger problem is they come back so fast. I would spray the plants, the next week they looked great with new clean foliage and the second week all the new growth is shriveled up and loaded with thrips. I think next year I'm going to treat them all with merit to try and slow them down and then alternate with Orthene and Conserve every two weeks.

Along with that a lot of them are going to be dug up to really work over the beds and then replant them properly. Change the irrigation from overhead spray to drip, etc, etc.

When is the best time to prune knockouts? One of my neighbors, pruned her knockouts SEVERLY a month ago... I mean these were 4' tall knockouts about 3 years old, and they pruned them about 1.5' off of the ground leaving no foilage. I was amazed to see new growth a couple weeks ago.

Around here it's recommended to do a hard pruning in August on knockouts. They way I do it is a heavy pruning in early January and then deadhead every two weeks through the growing season and then the cut back in Aug and then ride out the season deadheading as needed. For me that keeps them blooming strong all season.