Rudbeckia Are Generally Problem Free – But There Are A Few Issues To Look Out For
Chris is a gardening writer and nature enthusiast. He graduated from Oxford Brookes University in 2022 with an MA in Psychology. Chris works with the Leeds Green Action Society, helping their food cooperative by growing various fruit and vegetables on their two allotments in Hyde Park, Leeds.
Reviewed By COLIN SKELLY
Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.
IN THIS GUIDE
Rudbeckias are well-loved by gardeners around the globe and have become a staple in the British country garden.
Not only do gardeners love them but they are also beloved by helpful pollinators like butterflies and bees and are a source of food and shelter to many animals.
Rudbeckias are particularly popular because they are so easy to grow and take care of.
“Rudbeckias are the proverbial ‘bullet proof’ garden plant,” shares Horticultural Consultant Colin Skelly.
“The only problem I have ever had with Rudbeckia is slugs and snails on young plants. Once established, they look after themselves and only need dividing every few years.”
Like any plant though, there are a few problems you may run into.
The most common issues gardeners experience when growing rudbeckia include:
- Rudbeckia leaf spot
- Mildews
- Pests
See guidelines for dealing with each of these common problems below.
1) Rudbeckia Leaf Spot
Rudbeckia can suffer from both bacterial and fungal leaf spot diseases.
Bacterial Leaf Spot
Bacterial leaf spot disease will usually present itself as red-brown or brown spots on the leaves which will sometimes have yellow borders around them.
This type of disease can also cause the leaves to become malformed.
Fungal Leaf Spot
With fungal leaf spot diseases, you will often find tiny dark spots.
You will see this disease start at the base of the plant and gradually work its way upwards.
Preventing And Dealing With Leaf Spot
As with any problem, ideally, we want to prevent it from happening in the first place.
You can avoid leaf spot diseases by watering the plants at the base over the soil rather than watering them overhead.
If you find you have a leaf spot disease in your rudbeckias, we advise removing and destroying the affected areas or the whole plant if the disease is widespread.
Be sure to sterilise any equipment you use before and after to avoid the further spread of the disease.
2) Mildews
Powdery and downy mildew are both common problems with Rudbeckias.
Powdery Mildew
Powdery mildew usually becomes a problem in summer.
If you spot powdery white growth on the upper side of the leaves then powdery mildew is probably the culprit.
Left untreated the leaves will become yellow and eventually drop off.
If you notice powdery mildew on your plant you should remove and destroy the affected areas.
Downy Mildew
If you notice greyish-white, velvet-like growth on the underside of your leaves then you are probably dealing with downy mildew.
You may also notice dark spots on the upper areas of the plant.
Downy mildew can cause leaf drop and eventually kill the plant entirely.
To prevent downy mildew do not use overhead watering but rather water directly over the soil at the base of the plant.
3) Pests
Rudbeckias are usually untroubled by pests, however, aphids are quite partial to them.
To get rid of aphids you could start by setting natural enemies on them that eat aphids.
These can be bought at gardening centres or you can try and encourage them into your garden by planting their favourite plants.
If this doesn’t work we advise using a low-strength insecticidal soap and apply liberally to the plant.
As you can see rudbeckias are generally low-maintenance, making them perfect for novice gardeners!