Geranium Leaves Turning Red

If you’ve noticed your geranium leaves turning red, you’re not alone. This is a common sight for many gardeners, and it can mean several different things. Some causes are completely normal, while others signal your plant needs a little help. Let’s look at why this happens and what you can do about it.

Red leaves on geraniums often catch us by surprise. We expect those classic green leaves, so a crimson hue can be worrying. The good news is that in many cases, it’s not a serious problem. It can even be a sign of a healthy, hardy plant reacting to its environment.

However, it’s important to know the difference between a natural response and a cry for help. By understanding the reasons, you can make the right choice for your geraniums. You can decide whether to take action or simply admire the beautiful color change.

This specific heading covers the main topic. The red coloration in leaves is primarily due to pigments called anthocyanins. These are the same pigments that make blueberries blue and strawberries red. In geraniums, they’re always present in the leaves at a low level.

When certain conditions occur, the plant produces more anthocyanins. This can mask the green chlorophyll, leading to red, purple, or burgundy leaves. The trigger is often environmental stress. But remember, not all stress is bad stress.

Common Causes of Red Leaves on Geraniums

There are a few key reasons why your geranium might be showing this color. Some are part of the plant’s natural cycle, and others point to factors you can control. Identifying the correct cause is the first step to proper care.

1. Cool Temperatures (The Most Common Cause)

Geraniums are warm-weather plants. When temperatures drop, especially at night, they often respond by producing more anthocyanins. This is a protective mechanism. Think of it like the plant putting on a sweater.

This is very common in early spring or late fall.
It often starts at the leaf edges and moves inward.
The red color might be accompanied by slower growth.

If the cool weather is temporary, the plant will usually return to green as it warms up. This type of reddening is generally harmless and can be quite beautiful.

2. Sunlight Exposure and Sunscald

Geraniums love sun, but sometimes they can get too much of a good thing. Intense, direct sunlight—especially when combined with heat—can cause a sunburn effect. The leaves may turn red, then yellow, and finally brown and crispy.

South or west-facing exposures with reflected heat are often culprits.
New plants or ones moved suddenly from indoors to full sun are most at risk.
The reddening will be most severe on the leaves facing the sun.

This is the plant’s way of creating a “sunscreen.” The anthocyanins help protect the leaf tissues from further UV damage.

3. Nutrient Deficiencies

A lack of certain nutrients can interfere with chlorophyll production. When the green fades, the underlying red and yellow pigments become visible. The two most common deficiencies linked to red leaves are:

Phosphorus (P) Deficiency: This is a classic cause. The leaves, especially older ones, turn a dull, dark greenish-red or purple. Growth is often stunted.
Nitrogen (N) Deficiency: While usually causing yellowing (chlorosis), severe nitrogen lack can also lead to red or purple tints, starting with the older leaves.

Nutrient issues are more common in potted geraniums where soil reserves get depleted. It can also happen in very acidic or very alkaline garden soil.

4. Watering Issues

Both too much and too little water can stress your geranium and lead to red leaves. The plant’s systems get disrupted, triggering the anthocyanin response.

Overwatering: Soggy roots can’t take up nutrients properly, leading to deficiencies (like phosphorus) that cause red leaves. Leaves may also feel soft and limp.
Underwatering: Severe drought stress forces the plant into survival mode. Leaves can turn red or reddish-brown, become dry, and curl at the edges.

Consistent moisture is key. Geraniums prefer to dry out slightly between waterings but not to the point of wilting.

5. Natural Variegation and Genetics

Sometimes, it’s just in the plant’s genes! Many geranium varieties are bred for colorful foliage. If the reddening is symmetrical, appears on new growth, and the plant otherwise looks vigorous, it’s likely just its natural color.

Varieties like ‘Vancouver Centennial’ or ‘Happy Thought’ have beautiful bronze-red leaves normally.
Some zonal geraniums develop a dark “zone” or ring that can appear reddish.

In these cases, the red leaves are a feature, not a flaw. Enjoy the extra color in your garden.

How to Diagnose Your Geranium’s Red Leaves

Don’t guess—assess. Follow this simple checklist to figure out what’s going on with your plant.

Check the weather: Have nighttime temperatures been below 55°F (13°C)? If yes, cool temps are the likely cause.
Look at the pattern: Are only the sun-facing leaves red? Think sunscald. Are the lower/older leaves affected first? Think nutrient deficiency.
Feel the soil: Is it sopping wet or bone dry? Adjust your watering accordingly.
Examine the whole plant: Is it still growing and producing flowers? If yes, the issue is probably mild. Is it stunted, dropping leaves, or looking sickly? The problem is more serious.
Consider recent changes: Did you just repot it, move it, or start a new fertilizer? Any change can cause temporary stress.

Step-by-Step Solutions for Each Cause

Once you’ve identified the probable cause, here’s what to do.

For Cool Temperature Stress

This is usually a wait-and-see situation. If the plants are in the ground and frost is not expected, they will often acclimate. For potted geraniums, you can bring them indoors at night if possible. If you’re planting early in the season, choose a sheltered spot against a warm wall. There’s not much else to do, as this is a natural, non-harmful reaction.

For Sunlight and Heat Stress

Provide afternoon shade: Use a shade cloth or move pots to a location that gets morning sun and afternoon shade.
Avoid reflective heat: Move plants away from south or west-facing walls that radiate heat.
Acclimate plants slowly: When moving geraniums from indoors to outside, do it gradually over 7-10 days.
Do not prune the red leaves immediately. They are still functional and providing protection. Let them be until new growth comes in.

For Nutrient Deficiencies

Correcting a deficiency takes a little patience. First, ensure the problem isn’t caused by overwatering, which locks out nutrients.

Test your soil: A simple test kit can confirm low phosphorus or nitrogen levels.
Choose the right fertilizer: Use a balanced, water-soluble fertilizer (like a 10-10-10 or 20-20-20). For a suspected phosphorus boost, look for a formula with a higher middle number (e.g., 10-30-10).
Apply correctly: Feed your geraniums every 2-4 weeks during the growing season. Always water the soil first before applying fertilizer to prevent root burn.
For potted plants, consider repotting with fresh potting mix each spring. Old mix loses its nutrient content and structure.

For Watering Problems

Establishing a good watering routine is crucial. Geraniums like a “soak and dry” method.

Check before you water: Stick your finger about an inch into the soil. If it feels dry, it’s time to water.
Water deeply: When you water, do so thoroughly until water runs out the drainage holes. This encourages deep root growth.
Ensure excellent drainage: Pots must have drainage holes. In the garden, amend heavy clay soil with compost to improve drainage.
For overwatered plants, stop watering and let the soil dry out completely. You may need to gently remove the plant to check for root rot.

Prevention: Keeping Your Geranium Leaves Green

An ounce of prevention is worth a pound of cure. Follow these tips to minimize stress and keep your geraniums in top shape.

Plant in the right spot: Choose a location with at least 6 hours of morning sun and some protection from intense afternoon heat.
Use quality soil: Plant in well-draining potting mix or garden soil amended with compost.
Fertilize consistently: A regular, light feeding schedule is better than occasional heavy doses.
Water wisely: Learn the weight of your pots when dry vs. wet to help gauge moisture. Use mulch in garden beds to conserve moisture and keep roots cool.
Protect from early/late cold: Be ready to cover plants or bring pots in if an unseasonable cold snap is forecast.

When Red Leaves Are a Sign of a Bigger Problem

While often benign, red leaves can sometimes accompany more serious issues. Be concerned if you see the following:

Widespread reddening with yellowing and leaf drop: Could indicate a severe root problem from overwatering or disease.
Red spots or streaks with wilting: This could be a sign of a bacterial or fungal disease like blight.
Red leaves that are also distorted or curled: Might point to a pest infestation (like mites) or a viral infection.

In these cases, isolate the plant if possible. Remove severely affected leaves with clean shears. For suspected disease, you may need to use an appropriate fungicide or, in worst cases, dispose of the plant to protect others.

FAQ Section

Q: Is it bad if my geranium leaves are turning red?
A: Not necessarily. It’s very often a harmless response to cool weather or bright sun. You only need to worry if the plant also shows signs of decline like stunted growth, wilting, or leaf loss.

Q: Should I remove red leaves from my geranium?
A: No, not unless they are also crispy, brown, or diseased. Red leaves are still photosynthesizing and protecting the plant. Let them fall off naturally or remove them only once they are truly spent.

Q: What is the best fertilizer for geraniums with red leaves?
A: Start with a balanced fertilizer. If soil testing confirms a phosphorus deficiency, use a bloom-booster formula higher in phosphorus. Remember, proper watering is essential for nutrient uptake.

Q: Can overfertilizing cause red leaves?
A: Yes, it can. Too much fertilizer can damage roots (called “burn”), making them unable to absorb nutrients and water properly. This stress can lead to red leaves. Always follow label instructions.

Q: Do all types of geraniums get red leaves?
A: Most common zonal geraniums (Pelargonium x hortorum) are prone to it. Ivy, regal, and scented geraniums can also show red leaves, but it’s less common. Their stress signs might show differently.

Q: Will red geranium leaves turn green again?
A> It depends on the cause. If it’s from cool temps, they will often green up as weather warms. If it’s from a nutrient deficiency, new growth will come in green after you correct the problem. Sun-reddened leaves usually stay red or are replaced by new green leaves.

Q: How often should I water my geraniums?
A. There’s no fixed schedule. Water when the top inch of soil is dry. This could be daily in hot, windy weather, or weekly in cooler, cloudy conditions. Always check the soil moisture first.

Final Thoughts on Geranium Care

Seeing your geranium leaves turning red is mostly a chance to understand your plant better. It’s a visual cue telling you something about its environment. By observing carefully and responding appropriately, you can ensure your geraniums stay healthy and florish.

Most of the time, a little adjustment to watering, feeding, or placement is all that’s needed. The resilience of these plants is remarkable. With good basic care—plenty of light, consistent moisture, and regular feeding—your geraniums will reward you with vibrant greenery and plentiful blooms all season long. Paying attention to changes like red leaves is what makes you a thoughtful and successful gardener.