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help with knockouts

Discussion in 'Landscape Architecture and Design' started by clcscaper, Nov 13, 2008.

  1. clcscaper

    clcscaper LawnSite Member
    Messages: 31

    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?
  2. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    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.
  3. Dreams To Designs

    Dreams To Designs LawnSite Bronze Member
    Messages: 1,406

    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.

  4. clcscaper

    clcscaper LawnSite Member
    Messages: 31

    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?
  5. Spartan Pride

    Spartan Pride LawnSite Member
    Messages: 15

    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?
  6. clcscaper

    clcscaper LawnSite Member
    Messages: 31

    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.
  7. Dreams To Designs

    Dreams To Designs LawnSite Bronze Member
    Messages: 1,406

    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.

  8. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    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.
  9. PHS

    PHS LawnSite Senior Member
    Messages: 724

    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.
  10. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    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. :)

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