Mismatching the clematis vine’s conditions to its basic conditions is the most common reason for Clematis leaves turning yellow. Check that the soil, draining, and light condition are correct first. If the plant is being cultivated correctly, the yellowing may be caused by pests or diseases.
If you want clematis vines in your garden, don’t think of them as difficult to grow. In general, vines are among my favorite plants to cover my garden. And some of them certainly are finicky. But clematis vines are, in general, tolerant of a variety of conditions. They usually thrive once their basic needs are met.
When they do flounder, however, the first sign is usually yellowing leaves. This, of course, ruins their lovely effect, so let’s get to the bottom of the problem and fix it right away.
About Clematis Vines
These vines are beautiful, with trailing foliage full of colorful flowers that can be grown to cover walls and fences across the garden.
With bursts of vivid purple or pink, they are often known as “Queen of the Vines.” You can get them in a range of species and hybrids, with a wide range of flower shapes and sizes, allowing you to get the best ones for your garden.
To thrive, clematis vines will need some sun (about 6 hours a day), well-draining soil, and a light amount of pruning. However, if the plant's health suffers, you may see that pretty foliage turning yellow.
This guide will let you diagnose the problem and what steps you need to take to resolve it.
Improper Drainage
Leaving clematis roots sitting in water is a bad idea. The water blocks the vine from taking the nutrients it needs from the soil.
They need only one inch of water per week, and well-draining soil so that you can give them lots of water without it waterlogging the roots. It’s also a good idea to water clematis vines in the morning.
Heat and Sunlight
Clematis are fine with some shade. They need sunlight, but about 6 hours a day is enough. High heat can stress clematis vines and cause them to droop and yellow. Don’t worry, this will disappear as soon as the heat does.
Soil Nutrients for Clematis Vines
If your clematis has the right amount of water, the most likely cause of yellow leaves is magnesium deficiency. High-potassium fertilizers can interfere with the plant’s ability to uptake magnesium.
Check any fertilizer that you’ve used. If it’s high in potassium, this is likely to be the problem. Another sign is that the older leaves will turn yellow before the younger ones.
To treat it, mix a quarter cup of Epsom salts with a gallon of water. Spray this directly on the plant. You can also sprinkle the Epsom directly onto the soil.
Diseases That Affect Clematis Vines
Rust
Rust diseases cause yellow and orange splotches to appear on the plant. The disease thrives in high humidity and can be a result of overwatering and poor drainage.
Treat the condition by removing any foliage that’s affected and an organic fungicide.
Powdery Mildew
As well as yellow leaves, you will see a fuzzy covering on the leaves if they are affected by powdery mildew. The good news is that, though they may look bad, these infections are usually mild and don’t require treatment.
With the right amount of water and sunlight, this condition rarely affects plants.
Tomato Ringspot Virus
If the plant is suffering from the “tomato ringspot virus,” this is a more serious condition and you will need to dispose of the plant before it spreads.
Signs of this disease are streaks of yellow on the leaves, deformity, and stunted growth. This soilborne disease affects strawberries too, so be careful if these are planted near each other.
Pests that Affect Clematis Vines
Mites
The most common garden pests to affect clematis vine are mites. If you place a blank white piece of paper under the plant and shake it, you will see tiny black dots appear.
These are the culprits, and a sure way to discover if these are the culprits. Horticultural spray or oil applied every few days will help prevent these creatures from feeding on the vines.
Aphids
Aphids can infest clematis vines, turning them yellow as they feed. You will see a sticky trail of “honeydew” they produce as they feed. The nutrients they sap will kill the plant, so it is important to treat them straight away.
The first step is to dislodge as many as possible with a blast from your garden hose. After this, you can apply insecticidal neem oil to prevent their return and rid the plant of any remaining insects.
If you prefer, you can introduce ladybugs to the area. These are natural predators of aphids and will rid them of the plants.
Scales and Whiteflies
Scales and whiteflies can also infest clematis and sap nutrients from the plant. Solve this in a similar method to aphids, with a blast of water and application of insecticidal oil.
Frequently Asked Questions
Here is the answer to a few other common questions about clematis vines.
Q: When do clematis vines flower?
A: Clematis vines usually bloom in two waves. The first bloom is in late spring to early summer. They usually repeat bloom 2-3 months later.
Q: How often should you prune clematis?
A: Prune the vine yearly, cutting all stems back to a strong set of buds. The best time of year is March.
Q: What’s the best way to support clematis?
A: A mesh or trellis that protrudes an inch from the wall will allow your clematis vine to scramble up.
Clematis Leaves Turning Yellow – Conclusion
Though there are many factors that can turn your clematis vines yellow, most are not fatal. Using the advice above, you can tell what is causing the yellow leaves of your plant and make moves to change its care routine.
Soon after, the health of your vines will improve so that they can once again add magic to your garden.
Have problems with other plants' leaves yellowing? Check out our guide on how to determine why for your Kalanchoe or Oleander.