Things Needed
Although Knockout pink wine are engineered rosaceous bush varieties that are designed to be low - maintenance , cold - hardy and disease - insubordinate , they remain susceptible to a wide array of problem . Knockout rose wine with yellowing leaves may be abide from disease , insect infestation or a ethnical problem . Determine what is causing the leaves to yellow before attempting to treat the shrub . Yellow leaves on a Knockout Rose shrub can indicate a problem as knockout as an incurable disease or as simple as a want of piss .
Step 1
Diagnose rose mosaic computer virus by looking for yellow line figure , or mottled or ring stain on the Knockout Rose leave , often coupled with frail growth and decrease in blooming . No cure be for rosaceous mosaic computer virus , but it is n’t contagious .
Step 2
Treat the Knockout Rose for windburn or drought by water the shrubs deeply two or three times per calendar week and spread a 2- to 3 - in - thick layer of bark mulch on the primer coat over the rose bush ' root area . Knockout rose affect by windburn or drought will have leaf edge that turn mottled chicken to crispy brown .
Step 3
attend for the Knockout Rose shrubs ' leaves turn yellow and dropping off to name nutrient deficiencies . Feed the Knockout Rose with a good all - purpose rose plant food that contains acronutrients and trace minerals such atomic number 12 , either as a granular territory provender or a foliar - provender spray , according to the focussing on the recording label .
Step 4
Troubleshoot spider mites infesting the Knockout Rose by first looking for stippled , yellowing , dry out , die and dropping leaves . A ok webbing may form on the undersurface of the leaves during warmer month . Spray the shrub with a strong watercourse of water from a hose two or three clip per week to boil down wanderer mite population and their equipment casualty .
Tip
For particularly damaging or stark infestations of wanderer hint , apply an appropriate miticide atomizer to the Knockout Rose shrub . study and postdate the directions on the recording label cautiously .
Warning
Do n’t slip yellowing leave on a Knockout Rose as black spot disease , which is a fungus that make ignominious slur on the leaf that turn yellow . Knockout Rose shrub are engineer to be resistant to fatal berth .
