Common Garden Plant Diseases

Taking care of your garden, and all of the hard work that you have put into it can seem tiresome when garden plant diseases strike.

To learn more about common plant diseases, and how you can combat them, we have written a series of guides to the common signs of infection, treatment and prevention.

Powdery mildew

Of all the garden diseases, powdery mildew is one of the most widespread and easily recognised. No plants are safe from this disease, but it most commonly affects edible plants including apples, squash, cucumbers and ornamental flowers such as lilac, zinnia, rose and phlox.

The surface of the leaves develops spots or patches of white to greyish talcum powder-like growth.

To learn more, visit our powdery mildew guide.

Grey mould

Grey mould (botrytis) is a disease that can run riot if given a chance, especially in a greenhouse. This fuzzy grey mould grows on buds, leaves, flowers and fruit, attacking injured or stressed plants.

Once a plant is infected, botrytis may spread to all parts depending on its species and variety.

To learn more, visit our grey mould guide.

Plant rust

As its name suggests, garden rust is characterised by rust coloured spots and irregular discolouration on a plant’s leaves and stems. Rusts are fungal garden diseases and there are many different species affecting a variety of garden and greenhouse plants.

To learn more, visit our plant rust treatment guide.

Root rot

The most common cause of root rot is from over watering which can cause some of the roots to die due to a lack of oxygen. As the plants die they will start to rot. This can then spread to healthier roots and kill them as well, even if the soil conditions are put right.

To learn more, visit our root rot guide.

Rose black spot

This is one of the garden diseases specific to all types of roses. It takes the form of a black spot fungus and produces spores, which are released under wet conditions.

Small pin-head sized black spots on the leaves if unnoticed the spots increase in size to become large black or dark purple spots on the surface of the leaves or stem.

Rose black spot thrives in warm, wet weather, especially in the spring. Leaves less than two weeks old are most susceptible and spores can survive on fallen leaves and within the soil. It can be passed from plant to plant as well as on hands, clothing or tools.