My New Rose Bush's Bottom Leaves Are Turning Yellow With No Black Spots

Cause

• Yellow leaves on a rose bush can be symptomatic of a number of things. Yellow leaves concentrated at the bottom of the bush may be older leaves that are ready to fall. If the lower part of the rose bush develops yellow leaves in the summer, suspect a spider mite infestation. Spider mites generally remain toward the bottom of the plant on the undersides of older leaves. Spider mite populations build quickly in hot weather and can seriously weaken and damage the rose bush.

Additional Problems

• Ruling out other causes is the only way to determine if the yellow leaves on the bottom of the rose bush are a result of the natural process of the plant shedding older leaves. Look first for spider mites. Evidence of an infestation, aside from yellow leaves, includes fine webbing on the leaves, usually at the junction of leaf and stem.

Solution

• If you determine that the yellow leaves are old, either pull them off or wait until they fall by themselves. Rake them up so that they don't provide a breeding spot for pests or pathogens. Manage a spider mite infestation with a garden hose. Use a strong blast of water from the bottom to the middle of the plant to knock the mites from the leaves. Wait 3 days and then spray the rose bush again. According to master gardener Al Karsten, this disrupts the spider mites' breeding cycle. Check the rose bush in 1 week and if there are still signs of spider mites, repeat the spraying. Miticides work for heavy, persistent infestations.

Prevention

• The best way to prevent pest infestations, including spider mites, is to provide good cultural conditions in the rose garden. Rake the bed periodically to remove any leaves or other vegetation that may harbor the pests. Follow a consistent watering schedule to keep the rose strong and healthy. Although overhead watering is not recommended for roses, if you have continuous spider mite problems, give the plant a good overhead shower periodically during the hottest part of the summer. Water in the morning so the foliage dries before sundown.