How to Revive a Dying Rose Bush

The reason for a dying rose bush is usually because of water stress or a nutrient deficiency. Rose leaves can turn yellow and wilt as a result of both over and under watering. The fungal disease black spot (Diplocarpon rosae) causes rose leaves to turn yellow with black or brown blotchy spots.

Here is a summary of the most common reasons for dying rose bushes:

Keep reading to learn what is causing the problem with your rose bush and how to implement the solutions to save it…

Why are my Rose Bush Leaves Turning Yellow with Brown or Black Spots?

• Symptoms: Leaves develop black spots and the leaves turn yellow and eventually drop off.
• Causes: Black spot is a very common fungal disease by the name of Diplocarpon rosae.

Black spot is a very common disease which can present as black spots on green leaves as shown in the photo which then typically turns yellow as the rose battles the disease and loses its overall vigour.

Black spot is so common and such a problem for rose growers that even ‘black spot resistant’ roses eventually succumb to the disease as the fungus is genetically diverse and new strains arise that overcome the resistance.

Roses can survive black spot but it does affect growth and the abundance of flowers, so it is always important to get it treated.

Black spot is most prevalent when the weather in Summer is both warm and wet and can be also related to a shortage of potash (potassium) in the soil. However black spot is now so prevalent that it can spread even when conditions are not ideal.

How to Save a Yellowing Rose Bush with Black Spot

I have personally saved many roses with black spot with a combination of careful watering, pruning and the use of a fungicide spray.

• Increase the air circulation around the rose if you possibly can. Prune back any foliage from nearby shrubs or perhaps transplant the rose (either in the Spring or the Fall) to a more exposed area. The increased airflow creates a more hostile environment for fungal spores.
• When watering your rose bush, aim the hose or watering can at the base of the plant rather then overhead watering on the foliage and ideally water in the morning. The key is to avoid damp foliage as this increases the risk of black spot. If you water in the morning the rose is then charged with water for a hot sunny day ahead and any moisture that does happen to go on the leaves has a good opportunity to dry quickly.
• Cut back the most severely affected leaves, stems and branches to prevent the fungus spreading and burn it. Do not place it in the compost heap and clear up any leaves that may have dropped around the rose as this can harbour the fungal spores which can reinfect the bush.
• If almost all the rose’s leaves are infected with black spot then it becomes impractical to cut off all the leaves as this would prevent photosynthesis. In which case use a fungicidal spray (I bought mine from the local garden center). I often requires repeat applications of a fungicide to tackle a severe case of black spot so persistence is required.

Once the black spot infection has cleared up, remain vigilant for any signs of reinfection as the spores can be transported by the wind.

Apply a granular fertilizer in the Spring and Summer to address any nutrient deficits in the soil which should make your rose bush more resilient to infection.

I have personally bought and planted ‘disease resistant rose bushes’ and after 3 years or so they had black spot, such is the fungus’s ability to develop new strains that cause the disease, but by following the steps and the occasional use of the spray my rose collection is largely disease free.

Why are My Rose Bush Leaves Turning Yellow?

• Symptoms: Leaves can turn yellow or brown, droop and fall off.
• Causes: Water stress, poor drainage, too much or not enough fertilizer and seasonal change.

The above photo is of my rose with yellow leaves at the end of Fall coming up to Winter. Rose bushes are deciduous and lose their leaves every Winter, but the leaves turn yellow or brown before falling off. If your rose leaves are turning yellow before Winter, then you have nothing to worry about.

However water stress from underwatering, overwatering or poor drainage is more serious and can be fatal.

Roses need soil that retains moisture yet retains a porous open structure to allow excess water to drain away (so that the soil is not boggy).

This balance is achieved by planting the rose bush in organic matter (compost, manure and leaf mould) and by mulching every Spring to further improve the soil’s structure.

If the rose is planted in sandy soil, it drains too quickly for the rose to draw up any moisture whereas heavy clay retains too much water and can cause boggy conditions, both of which cause the roses leaves to turn yellow as a sign of stress.

It is also important to moderate your applications of fertilizer. Nutrient deficiencies (particularly as deficiency in nitrogen) turn the leaves yellow and reduce growth, whereas too much fertilizer can burn the roots and cause the leaves to turn yellow.

It is also important to acknowledge excessive fertilizer produces growth at the expense of flowers.

If the leaves are yellow with some brown then this is the result of severe of black spot. In which case follow the steps listed above this section.

How to Revive a Dying Rose Bush With Yellow Leaves

• If your soil is heavy clay and draining slowly, or the soil is sandy and draining too quickly it is important to transplant the rose bush to avoid root rot or drought stress. Roses cannot survive in boggy soil so move the rose to either a pot, raised bed or dig a hole 18 inches deep and across to remove the heavy clay or sandy soil and backfill with compost to create a more favourable soil structure.
• Apply a compost mulch every Spring on the surface of the soil as this integrate naturally into the soil over time further improves the soil structure and fertility of the soil.
• Apply a fertilizer that is specifically formulated for roses such as this miracle grow granular fertilizer which I use personally. This provides all the nutrients a rose needs at the right concentration to address any nutrient deficiencies. Roses are heavy feeders and generally benefit from additional fertilizer regardless of whether the leaves are turning yellow or not.

• Avoid apply fertilizer too often as too high a concentration is likely to result in yellowing leaves. If you use a granular product then this is less likely to be the problem. Keep in mind that I have seen people apply lawn fertilizer before rainfall which has then diluted and wash its way onto a nearby rose bed and caused the leaves to turn yellow.
• Rose typically only need to be watered once a week in Summer (although as often as every 3 days heat waves and pronounced drought) and once they have established after several years they do not typically require any watering, so scale back the watering if necessary.

If the leaves have turned yellow and you suspect the problem is too much fertilizer then the leaves are likely to stay yellow for the rest of the season and then drop off at the end of the year. I would refrain from applying any more fertilizer for the following year.

Give the soil a really good soak with a hose if you have applied too much fertilizer as this can help dissolve any accumulated salts from the fertilizer which should help the rose bush recover.