Yellow leaves on a rose bush can be a frustrating sight. When rose leaves turn yellow, it can ruin the overall effect of the rose bush. Rose leaves turning yellow and falling off can be caused by several things. Below are a few reasons why rose leaves turn yellow.
Causes of Yellow Leaves on Rose Bush
If you notice yellow leaves on a rose bush, you’ll need to determine the likely cause before treatment can take place. Here are some causes of yellow rose leaves:
Light– Rose leaves turn yellow and fall off at the bottom of the rose bushes at times when the upper leaves are shading them. The lower rose leaves are not getting the sunlight they need to, so the rose leaves turn yellow and drop off. When foliage is not getting the sunlight necessary for good growth, the bush simply allows the lower leaves to turn yellow and eventually drop. This is usually an age cycle thing and not harmful to the rose bush.
Heat stress– Another reason for rose leaves turning yellow is the rose bush is under some sort of stress. A common cause of stress is heat stress. The rose bush turns yellow and drops its foliage in an effort to cool down in the case of heat stress. Sometimes with other stressors the rose bush will start dropping foliage until the stress is relieved, whatever stress that may be.
Yellow leaves on rose bushes may also be caused by radiant heat. The ground or area below the rose bush is retaining too much heat, which then radiates up into the lower portions of the rose bush. This radiant heat causes heat stress and the lower foliage will turn yellow and fall off as the rose bush tries to protect itself and de-stress. Dark colored mulch or some rock mulches can hold too much heat in and reflect it back at the rose bushes. If there is a dark mulch or just the bare ground below your rose bushes, try using some shredded cedar mulch or some other light colored mulch all around the base of the rose bush, 24 inches (61 cm.) in diameter for younger rose bushes.
Water– Another source of reflected heat that can cause yellow rose leaves is water. If rose bushes are watered and the water is left to sit at the base of the rose bush, such that the sun’s rays are reflected off the water and up onto the lower foliage, the lower leaves will be somewhat burned. Thus, the rose foliage will turn yellow and fall off. To avoid this, keep your roses well watered but not soaking wet, and keep an eye on the soil moisture. If you do not have a moisture meter, just stick your finger into the dirt as far as you can. If it feels moist, there is no need to water the roses just yet.
Fertilizer– Sometimes the rose’s foliage can be burned by either too much granular fertilizer of foliar feeding (Miracle Gro) and it will burn the foliage such that it will turn yellow in places and fall off.
Nutrient deficiencies can be to blame too. Nitrogen, magnesium, and iron deficiencies can cause yellowing of the leaves. If treated correctly, the leaves regain their nice green color and do not reach the falling off stage. Make sure to research symptoms to recognize what you may be dealing with. Treating the roses for the wrong deficiency will only lengthen the stress period.
Pests or disease– Roses with yellow leaves can also be a sign that the rose has a pest or disease problem, of which there are many that cause yellow leaves. To help determine which it may be, look carefully on the rose bush for other signs of damage or symptoms of disease.
Treating Yellow Rose Leaves
While treating yellowing rose leaves on your plant depends on whatever the specific factor is that’s causing it, there are a few things you can do to help prevent problems by encouraging healthy growth.
Keep your rose bushes well watered but not soaking, soggy wet. Use a moisture meter prior to watering to see if watering is really necessary, or if it can wait two or three more days.
Water your roses either early in the morning or in the evening once the temps have started cooling off. Rinse the bushes off with good, clean water after a hot day. Plus, the rinsing of the foliage helps wash off contaminants of the day that can lead to foliage burn or other problems like insects.
Set up a feeding program for your rose bushes and stick to it. I like to alternate what fertilizer I give my roses, thus the program helps me remember which fertilizer gave the best performance. A well-fed and watered rose is far less likely to fall victim to many diseases.
Spend some time in your rose bed or garden checking their foliage (top and bottom of leaves) for any damage or insect presence. Early detection of a possible problem goes a very long way to its cure and to avoiding the frustration of dealing with rose plant leaves turning yellow.