Roses provide a beautiful staple in many gardens. They also are as resilient as they are attractive. Weed killer can seriously harm your rose, but most weed killers should not kill your plant. However, any weed killer should be used with caution around roses. Used improperly, weed killer can stunt growth, kill leaves and even stalks of your rose and inhibit flower formation for a season.
The recommended method of weed control for your rose garden is to hand-pick any existing weeds and apply a 3- to 4-inch layer of mulch. Placing a woven landscape cloth under the mulch will control the weeds in your garden for several years. Use caution when using tools to weed near your roses, as they may damage the plant's shallow roots. If you have a large garden, invasive weeds and an herbicide is needed, there are specific chemicals deemed safer for roses.
Pre-emergent herbicides--those that kill the weed by inhibiting germination of the seed--are less likely to damage your rose bush. These herbicides primarily control grasses, but also will stop the production of a few broadleaved weeds such as spurge and oxalis.
If a post-emergent herbicide is desired for existing weeds, chose a day with no wind to reduce possible damage due to drift. Some herbicides have been known to drift for 100 yards or more.
To reduce possible damage to your rose bush, cut a 2-liter bottle in half and place it over the weed. Spray the herbicide into the open end of the bottle and move onto the next weed. Continue until all the weeds are treated. For most weeds, only one treatment is necessary, but for perennial weeds, such as Bermuda grass, a follow-up treatment may be required. It takes up to six hours for the herbicide to become rain-fast, so spray on a clear day, when no danger of rain is present. Don't water your garden for six hours to prevent spread of the herbicide to nearby plants.
Signs of Damage
Although roses are resistant to most weed killers, when exposed, you'll see yellowing, curled or limp leaves and weakened stems. The effects may be long-lasting. The spring after a fall exposure may result in your rose buds breaking off the stem before blooming.
Prune off the damaged stalks and continue watering and feeding as usual. Your rose plant should recover by next spring.