Geraniums, also known as Pelargoniums, are a popular species of flowering plants that are native to southern Africa. These perennials are known for their vibrant and colourful blooms, which come in a variety of shapes and sizes.
There are over 200 different species of geraniums, and they can be divided into several different groups based on their characteristics. The most common types of geraniums include the zonal, ivy-leaved, scented, and species geraniums.
Zonal geraniums are the most popular variety, and they are known for their distinctive zone or band of colour around the edge of the leaf. These geraniums come in a wide range of colours including red, pink, white, and salmon. They can be grown as bedding plants or in pots, and they are often used in hanging baskets or window boxes.
Ivy-leaved geraniums are another popular variety, and they are known for their trailing habit and ivy-shaped leaves. These geraniums are often used in hanging baskets or window boxes, and they come in a wide range of colours including red, pink, and white.
Scented geraniums are another type of geranium, and they are known for their fragrant leaves. These geraniums come in a variety of scents including lemon, rose, and mint. They are often used in perfumes and potpourri, and they are also popular in herb gardens.
Species geraniums are the wild relatives of the cultivated geraniums. They are usually smaller in size and have smaller flowers, but they often have a longer blooming period and are more tolerant of poor soil and drought conditions.
Geraniums are hardy plants that are easy to grow and care for. They prefer well-drained soil and full sun, and they should be watered regularly. Geraniums can be propagated by taking stem cuttings in late summer or early fall. (We recommend using this rooting hormone to help root formation in your cuttings.)
Geraniums are one of the most popular flowering plants grown in gardens and containers. Native to South Africa these cheerful bloomers brighten patios borders, and balcony gardens with their vibrant flowers and lush leaves.
However, geranium leaves sometimes turn from green to red, which can be alarming for gardeners So why do geranium leaves turn red, and what can you do about it?
Reasons for Reddening Geranium Foliage
There are several potential causes of red leaves on geraniums
1. Cool Temperatures
Geraniums thrive in warm weather and can suffer from shock when exposed to cool or fluctuating temperatures. This stress often turns their leaves red, especially in spring and fall when temperatures rise and dip. Container-grown geraniums are particularly prone as their roots are more exposed to temperature changes.
2. Overwatering
Too much moisture is a common culprit behind red geranium leaves. Geraniums prefer moderately moist, well-drained soil. When overwatered, their roots suffocate, unable to access oxygen. This stresses the plant, causing leaves to redden and potentially drop.
3. Underwatering
While overwatering is more common, underwatering can also turn geranium leaves red. If the soil dries out too much between waterings, the plant becomes stressed. Leaves redden and wilt as the geranium struggles to absorb sufficient moisture.
4. Sunburn
Geraniums need lots of sun but can get sunburned if light levels are excessive, especially on hot, bright days. This manifests as reddish spots or scorches on the most exposed leaves. Moving the plant to light shade prevents further sun damage.
5. Mineral Deficiencies
Lack of phosphorus and other minerals can starve geraniums of nutrients vital for photosynthesis and growth. This deficiency stress makes their older leaves turn red. Fertilizing with phosphorus-rich plant food restores health.
6. Diseases
While less common, fungal diseases like leaf rust can cause red/brown lesions on geranium foliage. These develop as spots on leaf undersides rather than the whole leaf reddening.
Solutions for Red Geranium Leaves
Now that we’ve covered the reasons behind reddening geranium foliage, let’s discuss solutions to restore their normal, vibrant color:
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Adjust watering – Check soil moisture before watering and only water when the top 1-2 inches become dry. Empty excess water from saucers after 30 minutes. This prevents over and underwatering.
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Move containers – Bring potted geraniums indoors or under cover during cold snaps and temperature drops. This protects their roots from chill damage.
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Provide shade – Filter sunlight with sheer curtains or move containers to a spot with light afternoon/midday shade. This prevents sunburn.
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Fertilize regularly – Feed every 2-4 weeks with a balanced liquid fertilizer or slow-release granular plant food. This prevents nutrient deficiencies.
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Prune affected leaves – Remove any leaves which are entirely red to promote new healthy growth. Make cuts just above the leaf joints with clean shears.
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Treat diseases – If fungal leaf spots are present, apply suitable organic fungicides like neem oil, sulfur, or copper soap. Always follow label directions.
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Repot annually – Refresh potting mix and increase container size every spring so roots have room to grow. Use porous soil and add drainage material.
With proper site selection, watering, fertilization, and care, geranium foliage will remain lush and green all season long. Red leaves are usually an easy fix. Just diagnose the cause and implement solutions to restore your geraniums to colorful health. With a bit of attention, you can enjoy these classics for years to come.
Frequently Asked Questions about Red Geranium Leaves
To summarize key points about reddening geranium foliage, here are answers to some common questions:
Why are my geranium leaves turning red?
The main causes of red geranium leaves are cool temperatures, overwatering, underwatering, sunburn, mineral deficiencies, and diseases. Identify the cause and adjust care accordingly.
Should I remove red leaves from my geraniums?
Yes, pruning off fully red or mostly red leaves promotes new healthy growth. Make clean cuts just above the joints using sterilized pruning shears.
How can I prevent red geranium leaves?
Proper planting site, attentive watering, fertilization, pruning, and disease management prevents almost all cases of reddening geranium foliage.
Are red leaves bad for geraniums?
Red leaves mean the plant is stressed. While not immediately fatal, long-term stress weakens geraniums and makes them prone to decline. Address the cause before extensive leaf loss occurs.
What deficiencies cause red geranium leaves?
Lack of phosphorus and other nutrients due to insufficient fertilizer can lead to red geranium foliage. Apply a balanced plant food every 2-4 weeks.
Should I bring geraniums with red leaves indoors for winter?
No, it’s best to discard stressed geraniums with extensive leaf reddening before overwintering. Start fresh with vigorous new plants the following spring.
By understanding what makes geranium foliage turn red and taking prompt action, you can restore their vibrant color and keep these classics flourishing. With the right care, geraniums will thank you with endless flowers and foliage all season long.
Why are my geranium leaves turning red?
Geranium leaves can turn red for a variety of reasons, including:
- A lack of water: Red leaves can be a sign of drought stress. Scratch away soil from the top 3-5cm, if the soil is dry then the geranium needs water and this is what could be causing the leaves to turn red. Give the geranium a deep watering by hand, add some wetting agents to help the water penetrate the soil and Seasol to help the plant recover from the stress. (This product is great for helping with heat stress; best applied before the stress but can also help after or during a heat wave.)
- Genetics: Some varieties of geraniums have red or bronze-coloured leaves as part of their natural coloration. If this is the case, the leaves turning red is normal and not a cause for concern.
- Sun exposure: Geraniums prefer full sun to partial shade, and prolonged exposure to direct sunlight can cause the leaves to turn red. This is a natural response to protect the plant from sun damage, and it is not harmful to the plant.
- Temperature: Geraniums prefer temperatures between 60-75°F (15-24°C), and exposure to extreme heat or cold can cause the leaves to turn red. This is a sign that the plant is stressed, and it is important to move the plant to a more suitable location or provide protection from extreme temperatures.
- Disease: Red coloration on the leaves can also be a symptom of a fungal or viral disease, such as powdery mildew, botrytis, or verticillium wilt. If you notice any other symptoms such as wilting, yellowing, or browning of the leaves, it’s important to consult with a professional for diagnosis and treatment.
- Nutrient Deficiency: Geraniums need specific nutrient to grow and bloom, if they are not getting enough of these nutrients, it can cause the leaves to turn red. This can be due to a lack of fertilisation or poor soil quality.
It’s important to note that in all cases, it’s always good to check for other symptoms, such as wilting, yellowing, or browning of the leaves, to identify the causes and take the appropriate action.
Growing geraniums in the ground:
- Advantages: Geraniums planted in the ground have a larger root system, which allows them to access more water and nutrients. They also benefit from natural rainfall, which can help to reduce the need for watering. Geraniums planted in the ground can also establish deeper roots, which can help them to survive through dry periods.
- Disadvantages: Some people will not have space to plant a geranium in the ground, so the only option is to plant in a pot.
In conclusion, Geraniums can be grown in pots or in the ground, and the best option depends on your personal preference and the conditions of your garden. Geraniums grown in pots are easy to move around and can be placed in different locations, but they will dry out faster and will need to be watered more frequently. Geraniums planted in the ground have a larger root system, and can establish deeper roots, but they are more affected by the soil and weather conditions and can be difficult to move around.