How to prune canna lilies – to keep them looking healthy all season long

Canna lilies, vibrant and tropical-looking, will add bold color to your garden. To help them stay healthy year round, canna lilies need pruning. 

How, and how much, you have to prune canna lilies depends not only on the plant's state, but also the season. Canna lilies can produce beautiful flowers during spring and through to colder seasons, and towards the end of their bloom cycle they produce seeds that can be replanted during April and May. 

After their blooming is complete when the first frost hits, canna lilies should be pruned right down to keep them healthy. Follow our expert tips to know when and how to correctly prune your canna lilies to keep them healthy and thriving.

Why is it important to prune canna lilies?

Pruning canna lilies is a great way to 'reset' the plant. What this means is that by removing unhealthy or dead foliage the plant can focus on growing new healthier and stronger foliage.

Zahid Adnan, gardening expert and founder of The Plant Bible says, 'Pruning canna lilies helps maintain their overall health and appearance while encouraging robust growth and abundant flowering. By following pruning techniques, gardeners can ensure that their canna lilies thrive and contribute to the beauty of outdoor spaces.'

Gardening expert Drew Swainston at Homes & Gardens adds: 'Cannas can produce many blooms throughout the summer so can benefit from being deadheaded. This will stop the plant putting a lot of energy into producing seed and can encourage further flowering.'

Zahid Adnan

Zahid Adnan is the Founder and Editor of The Plant Bible , as well as managing a plot of 10-hectare agricultural land. He is also involved in a project to develop sustainable urban farming practices by utilizing farming technologies to increase food production and reduce environmental impacts.

Drew Swainston

Drew qualified as a journalist before studying for a horticulture qualification, after which he worked as a professional gardener for several years, specializing in kitchen gardening. He's now bringing his expertise and passion to Homes & Gardens as a member of our team. 

How to prune canna lilies

First, you should remove spent flower stalks. Stephen Sullivan, Editor at PlantNative advises: 'I begin by cutting back the canna stalks, about 4 to 6 inches from the ground. The goal is to remove the spent flower stalks and any dead or damaged foliage. As I trim away the old growth, I'm always mindful of maintaining the plant's overall shape and balance. I aim for a clean and tidy appearance, removing any straggling or unsightly stems. By doing so, I encourage new growth and prevent the plant from becoming unruly.'

Zahid Adnan suggests that 'after canna lilies finish blooming, it's advisable to remove the spent flower stalks. Trim the stalks back to their base using pruning shears or a sharp knife. This practice encourages the plant to direct its energy towards root and foliage growth rather than seed production.' 

When cutting off the dying or dead flowers, prune the stem to the node where this part of the plant joins the main stem.

Zahid continues, 'Trim foliage: as the growing season progresses, some of the lower leaves on canna lilies may become yellow or damaged. Prune these leaves individually by cutting them back to the base of the plant. However, avoid excessive removal of healthy foliage, as it plays a crucial role in the plant's photosynthesis and overall vigor.'

When dealing with canna lilies connected by a stem, Drew Swainston says, 'As cannas can flower on the same stem, pick a spent bloom and carefully snip or pinch it off, taking care not to damage any other buds.'

Don't cut the stem when trimming the canna lilies, instead chop where the dead leaves and the stem connect. This may mean you trim off single leaves at a time or even whole sections of leaves if they are all looking spent.

Finally, Zahid Adnan recommends, 'Every few years, canna lilies benefit from division to rejuvenate the plant and promote healthier growth. The ideal time to divide canna lilies is in early spring before new growth emerges. Dig up the clump, separate the rhizomes, and replant them in well-prepared soil. Ensure each divided section has a healthy rhizome with viable buds.'

Stephen Sullivan

Stephen Sullivan is the editor at PlantNative. PlantNative is dedicated to moving native plants and naturescaping into mainstream landscaping practices. They believe this promotes biodiversity, preserves our natural heritage, reduces pollution and enhances livability. Their goal is to work with nursery owners, landscape professionals and consumers to increase public awareness of native plants and related landscaping practices and to increase both the supply of and demand for native plants.

When is the best time to prune canna lilies?

Zahid Adnan, gardening expert and founder of The Plant Bible recommends, 'The best time to prune canna lilies depends on your climate and the specific variety of canna lily you are growing. 

Canna lilies actually originate from Mexico. With its warmer climate, we can understand why canna lilies prefer hotter climates.

It is important to prune them regularly during summer to prolong their flourishing. Stephen Sullivan suggests, 'When the growing season comes to an end and the foliage starts to fade or when the first frost hits, it's time to prune the canna lilies.'

'In regions with mild winters, canna lilies can be pruned in late fall or early winter when the foliage starts to die back naturally. This timing allows the plant to enter a period of dormancy without the risk of frost damage,' says Zahid Adnan. 

Bryan Clayton, CEO of GreenPal adds: 'In my experience, the best time to prune canna lilies is in the late fall or early winter, after the first frost. Frost typically signals the plant to go dormant, which is when you want to start your pruning. 

Pruning back canna lilies quite severely is ideal during winter, because the plant will simply regrow in warmer seasons. Just make sure that you have checked for any seed pods first, and taken them to use to replant your canna lilies before you give the plant the chop. 

'In colder climates, it's best to wait until early spring, just before new growth emerges, to prune canna lilies,' continues Zahid Adnan.

Drew Swainston agrees: 'Cannas can be pruned after the first frosts and cut back to around 6 inches from the ground. They can survive this hard pruning and will grow back next year.'

Bryan Clayton says, 'It's important to wait for the first frost because premature pruning can make the plant vulnerable to pests and diseases.'

Also remember, if all of the foliage and flowers on your canna lily plant are brown then it's okay to cut the plant right down to the stem which will simply reset the plant for next season. They are quite resilient plants so don't worry if you have to take drastic pruning steps – this is still better than leaving the plant to turn completely brown.

'Based on the results I've seen, this routine of proper timing, pruning, and care can keep your canna lilies looking their best and bring a splash of tropical flair to your garden for years to come,' comments Bryan Clayton.

Bryan Clayton

Bryan Clayton is the CEO of GreenPal, an online marketplace for landscaping services. Bryan has over two decades in the landscaping industry. Prior to founding GreenPal, Bryan started Peachtree Inc., a landscaping company in Tennessee.

4 tips for successful canna lily pruning

1. Clean your tools before pruning

Zahid Adnan recommends ensuring you're using clean tools: 'Use clean and sharp pruning tools to make precise cuts without causing damage or introducing potential diseases. Disinfect the tools before and after use to minimize the risk of spreading pathogens between plants.'

We recommend properly researching how to clean your garden tools in order to make pruning easier and avoiding reversing all your hard pruning work. McKesson Isopropyl Rubbing Alcohol from Walmart can be used to effectively ensure your garden tools are sanitized.

2. Mulch

Next, he recommends mulching: 'Apply a layer of organic mulch around the base of canna lilies after pruning. Mulch helps conserve moisture, suppress weeds, and insulate the soil, providing favorable growing conditions for the plants.'

3. Feed

'After pruning and dividing canna lilies, provide them with a balanced slow-release fertilizer to support their growth and flowering. Follow the manufacturer's instructions for application rates and frequency.'

A good fertilizer for snapdragons is an Expert Gardener Flower Plant Food Fertilizer, with a 10-10-10 ratio, available at Walmart.

'In terms of long-term care, I always recommend a balanced, slow-release fertilizer for canna lilies in the spring and early summer.' 

We recommend Osmocote Smart-Release Plant Food from Walmart.

4. Check for pests and disease

'Regularly inspect canna lilies for pests, such as aphids or caterpillars, and promptly take appropriate measures to control them. Additionally, keep an eye out for common diseases like leaf spot or fungal infections, and address them using appropriate treatments.'

Bryan Clayton also advises to take caution if your canna lily has diseased foliage, 'Remember to remove any dead or diseased foliage during the growing season. This helps to keep the plant healthy and also encourages more blooms. 

'Let me explain why it's crucial to dispose of the cuttings properly, especially if they're diseased. You don't want to inadvertently spread any diseases to other parts of your garden.'

FAQs

Canna lilies are a great addition to any garden, and having the know how to prune these beautiful plants will keep these them alive and healthy year round without needing to replant. And if you harvest last season's canna lily seeds you have a ready stock of new plants for next year.