Rose Troubleshooting!

Black Spot

What is it? Rose black spot is a common fungal disease affecting the foliage. Dark purple-black spots appear on the leaves and stems. Although unsightly, black spot will not affect the health of the rose unless allowed to completely take over the rose.

How to treat it:

• We advise removing all affected foliage and dispose of it away from the plant.
• There are various topical treatments you can use. We recommend using a Plant Invigorator Spray. This particular spray is also a foliar feed. Affected foliage will still need removing – these treatments are not “cures” but will protect against any further bouts.
• If using gloves or pruners on a rose with blackspot, make sure to wash them before moving on to another rose to avoid contamination.

For more information, see our Common Rose Problems guide.

Powdery Mildew

What is it? Rose powdery mildew is a fungal disease, that is usually noticed first on the leaves but can appear on any part of the plant. It appears as a white, powdery growth, and can disfigure leaves and buds if left untreated. New shoots and leaves are more susceptible, and will often appear after the temperatures start to rise.

Much like other fungal diseases, powdery mildew is spread via airborne spores, and can lay dormant over the winter. Mildew is usually an issue during dry summers, and particularly likes high air humidity, dry soil, and poor air flow.

How to treat it:

• Prune out and bin infected leaves, and keep the soil around the roots moist at all times.
• Mulch in late winter to aid soil water retention.
• Grow roses with lots of room around them so the air can circulate

Rust

What is it? Rose rust is a fungal disease that affects the leaves of a rose. Many strains of rust only affect roses. Rust is first noticeable as orange coloured spots on the underside of leaves. As these mature they turn black, and also cause a distinctive mottling on the tops of the leaves.

How to treat it:

• We advise pruning off all affected foliage and stems, and dispose of it away from the plant.
• There are various topical treatments you can use. We recommend using a Plant Invigorator Spray.
• Grow roses with lots of room around them so the air can circulate, and prune out any congested stems/foliage.

Nutrient Deficiency

What is it? Nutrient deficiency occurs when the rose is struggling to obtain all the nutrients it needs to grow. It can present with a number of symptoms, including weak stems, discoloured leaves, buds that fail to open, and increased susceptibility to other issues such as blackspot. The good news is that it is easy to treat, and regular feeding helps avoid the issue entirely.

How to treat it:

• Avoid this in the long-term by mulching each year with good quality compost.
• We recommend feeding the rose with a rose specific feed as soon as you notice the problem. Foliar feed or liquid soil feed are quickly absorbed, and will give your plant a quick boost of nutrients that is easily accessible.

For further information about Nutrient Deficiency in roses, take a look at our Common Rose Problems guide.

Aphids

What are they? Aphids are insects that love roses, in particular the younger, softer growth of new leaves and flower buds. They are particularly active in early spring, but are very common garden visitors all summer long. Although unwanted, aphids are virtually harmless to the rose unless allowed to remain there long term.

How to treat it:

• We recommend brushing them off with a paintbrush, or wash them off with a hose or jet of water.
• Plant herbs such as basil and chives that are a natural repellant to aphids – available in the garden herb seedball mix for easy planting.
• You can also buy and release ladybirds onto infested roses to eat the aphids.
• Grow plants for natural aphid enemies like hover-flies – they’re particularly fond of umbellifers like fennel, cow parsley and sweet alyssum.