Calla lily plants have bright flowers and are easy to grow but some problems can cause their leaves to turn yellow. The top causes of yellow leaves on calla lilies are caterpillars, snails and slugs, a lack of nutrients including nitrogen and too much water.
There are some easy ways to solve each of these problems and this article will explore all you need know to save your Calla lily.
Causes of yellow Calla lily leaves and solutions
Here are the top 5 causes of yellow leaves on calla lilies and how to solve each one.
1. Caterpillar nibbles
One of the top causes of yellow marks on calla lily leaves is attack by caterpillars. These bugs can nibble the middle or edges of the leaves. You will see holes or marks that will turn yellow on the edges. These are usually recognizable bite marks and otherwise the leaf will look clean.
Dealing with caterpillars naturally in your garden is the best approach. If there are only a few nibbles you can let the birds move in and eat them.
Egg shell caterpillar traps
Use broken egg shells to attract passing cabbage white butterflies who will lay their eggs on the shells. While these caterpillars usually attack cabbages, they can also eat your calla lilies.
Bacillus thuringiensis (Bt)
For a natural caterpillar treatment Bacillus thuringiensis is bacteria that has been developed into a spray called Dipel. This spray is designed only to kill caterpillars and will take a few days to work.
2. Snails and slugs
Snails and slugs love calla lily leaves and can cause them to turn yellow where they have been eaten. Snails and slugs attack during the night so you usually can’t see them but see the results of their chewing.
The other thing to look for to know it is slugs or snails is a silver line or marks that come from their trails.
3. Lack of nitrogen
A range of nutrients are essential for healthy leaf growth on calla lilies and if they lack any, including nitrogen the leaves can turn yellow. If the whole leaf starts to turn yellow this is a nitrogen problem. If the veins stay green but the rest of the leaf is yellow then it could lack iron.
Calla lilies grow best if they get regular all-purpose organic fertilizer. I add slow release pelleted chicken manure in fall and spring to give them a range of nutrients and to feed the soil bacteria and worms. If you notice green veins and yellow leaves add some iron chelates.
4. Too much water
Too much water can wash away key water soluble nutrients including nitrogen from your calla lily causing the leave to turn yellow. Too much water can also cause fungal growth in the soil and on the roots, causing root rot. This stops the plant from absorbing the nutrients and water it needs and can cause yellow leaves.
If it is you that is adding more water, slow down your schedule and only add water once the soil is dry 2 inches below the surface. Calla lilies like moist soil but if you have high rainfall you may not need to add any extra yourself. We having getting a very rainy spring and summer so after I planted my lily out I haven’t had to water it.
5. Not enough water
Another cause of yellowing leaves on calla lilies is a lack of water. Calla lilies are tropical and are tolerant of dry spells but letting them dry out too much can cause the leaves to turn yellow and then brown.
Act quickly to moisten the soil and revive your calla lily. If your plant is in a pot, you can place the whole pot in a bucket of water to soak through. Add a dash of liquid seaweed to help to revive the roots. Take the pot out and let it drain well. Water the plant every 4-7 days to keep it moist for the next 2 weeks.
Calla lilies planted in the ground can be deep watered with your hose. Always cover the surface of the soil with mulch like bark or sugar cane. You can mix the two together for a great mulch that will keep water in the soil and break down to improve it over time.
Calla Lily Leaves Turning Yellow | Summary
Calla lilies are hardy plants but their leaves can turn yellow if they are not cared for or if they suffer from bug attack. Look out for snail or slug trails or caterpillar bite marks. Check the soil to see if it feels dry or wet and make an adjustment to your watering schedule. Always surround your plant with mulch and give it some slow release fertilizer in spring and fall.
My new calla lily is taking pride of place in the middle of my yard. It is planted next to some standard canna lilies and in front of my new mango tree. It is thriving with big, bright purple flowers and the high rainfall we are having.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.