Geraniums are highly sought-after flowering plants that produce attractive pink, purple, white, or red blooms, adding a Mediterranean cheer to your garden or flower bed. They are easy to grow and maintain and have eye-catching, scented foliage. However, you might be wondering how to keep the leaves of your geraniums green throughout the growing season.
Here are 7 effective ways of keeping geranium leaves green:
- Plant your geraniums in suitable soil.
- Avoid overwatering or underwatering your geraniums.
- Keep your geraniums well nourished.
- Protect your geraniums from pests and diseases.
- Meet your geraniums’ sunlight requirements.
- Protect your geraniums from cold snaps.
- Avoid using herbicides on your geraniums.
This article explores various methods of maintaining the green color of geranium leaves. So, keep reading to learn more.
1. Plant You Geraniums in Suitable Soil
Geraniums (pelargoniums) are perennial flowering plants that can also grow as annuals. These gorgeous plants have evergreen leaves if planted in suitable soil during their growing season. Hence, any yellowing or discoloration of the leaves could mean an issue with the soil or potting mix.
Understand Your Species of Geranium
However, before we explore this possibility further, it’s essential to note some facts about geraniums:
What most people in the US refer to as ‘geraniums’ are actually pelargoniums. Both are genera of flowering plants that belong to the Geraniaceae family and have some similarities. But a distinct difference between the two plants is that true (hardy) geraniums have five similar petals. However, in pelargoniums, the upper two petals are different from the lower three, giving them a pom-pom appearance.
So, in this article, we’ll focus on the geraniums (storks bills) in the genus Pelargonium.
Plant Geraniums in Well-Draining Soil
Although geraniums can grow in any soil type, they thrive in rich, well-draining soil with medium moisture. Moreover, since they lack an extensive root system, the plants will do well in porous soil where the roots can breathe and absorb minerals. And potted geraniums don’t mind shallow containers since their roots don’t grow deep into the soil.
Planting your geraniums in compact, waterlogged soil will harm your plants’ health since the roots can’t absorb nutrients from the soil. Furthermore, the roots can’t translocate dissolved nutrients to other parts of the plant. Consequently, the leaves won’t receive their share of nutrients from the root system, hence, turning yellow.
If you’re growing your geraniums outdoors, it would be best to plant them in loamy soil since they are rich in organic matter and well-draining. So, your plants will thrive, and their leaves will remain green throughout the growing season.
However, if this soil type is unavailable, adding compost to your garden soil is a suitable way to improve its drainage. So, you can spread a compost cover of about 2 to 4 inches (5 – 10cm) to the 6- to 12-inch (15 – 30cm) top layer of your soil.
Consider Using a Potting Mix
If you want to grow your geraniums indoors or on overhanging baskets, a soilless growing medium (potting mix) would be ideal. However, you must ensure that it is best suited for your plants such that it doesn’t drain too rapidly or retain a lot of moisture.
Also, ensure that the potting mix has the correct pH since geraniums prefer a pH range of 5.8 to 6.5. Some potting mixes with peat might be too acidic, and you might have to add some lime to neutralize them a bit.
If you prefer growing your geraniums in raised flower beds, it’s preferable to mix your garden soil with the potting mix to ensure proper drainage. However, some gardeners prefer using commercial raised bed soil since it has the perfect consistency and drainage.
2. Avoid Overwatering or Underwatering Your Geraniums
Geraniums are hardy, drought-resistant plants. Nevertheless, they love to grow in soils with medium moisture. Moreover, it’s challenging for most gardeners to find the right water balance, and many either overwater or underwater their geraniums.
Signs That You’re Overwatering Geraniums
Some gardeners overdo the watering, and geraniums can’t stand it; they hate sitting in wet, soggy soil.
Therefore, you’ll know that you’re overwatering your plants if you notice the following signs:
- Yellowing of leaves, especially the lower ones
- Pale water spots
- Waterlogged soil
Most people overwater their outdoor geraniums in spring or summer when there are some rainfall episodes. You can also overwater your indoor plants if the soil or growing container isn’t draining correctly.
Therefore, it’s essential to have a watering schedule. It can be once per week in typical situations or once daily (morning or evening) during hot weather.
However, this might depend on some factors, including the following:
- Your soil type
- The season and weather conditions
- The growing environment
Only water your geraniums when it’s clear they need a drink. The best way to determine this is by doing a test using your fingers. If the topsoil feels dry, you can water your plants. But ensure that you irrigate your plants by focusing on the roots—avoid wetting the leaves.
Signs That You’re Underwatering Geraniums
Since geraniums are drought-tolerant, they can bear an extended period of dryness or heat waves. However, this doesn’t mean you should neglect their water requirements. The plants need some water once in a while, and they’ll be stressed if they don’t get any for a long time.
You’ll know that you’ve underwatered your geraniums if you notice the following:
- Yellowing of the leaf edges
- Drooping leaves
Therefore, it would be best to water your geraniums when the soil feels dry, as we’ve already established. Furthermore, avoid drenching the soil since geraniums can’t stand waterlogged soil.
You might need to occasionally monitor the soil’s moisture to ensure that your plants have the correct amount. Consider using a meter to test the moisture levels.
3. Keep Your Geraniums Well Nourished
Geraniums are moderate-to-heavy feeders. Like other flowering plants, they require regular feeding to grow healthy and bloom in time. Moreover, geranium leaves are dark green when they have an adequate supply of nutrients, including nitrogen, potassium, phosphorus, iron, and manganese.
Hence, they’ll start turning yellow or have other discolorations due to nutrient deficiencies. Furthermore, this phenomenon is common with potted flowering plants that have been growing in these containers for months or even years.
So, if you notice that your geranium leaves are turning pale green, yellow, or have other discolorations, it’s crucial to determine if they’re undernourished. However, it’s confusing to tell the specific nutrient that your plants could be lacking. Hence, it’s essential to know what to look out for.
Here’s a table that elaborates on geranium nutrient deficiencies and their symptoms:
| Nutrient | Role in Plant | Deficiency Symptoms |
| Nitrogen | Essential in plants’ growth and development |
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| Phosphorus | Production of proteins, DNA, RNA, and cell membranes |
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| Potassium | Starch formation, drought tolerance, pH stabilization, cell turgor, and enzyme activation |
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| Sulfur | Protein synthesis, respiration, and photosynthesis |
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| Magnesium | Formation of chlorophyll, enzyme and cofactor reactions, carbohydrate metabolism, stabilizing cell membranes |
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| Iron | Chlorophyll, DNA, and RNA formation, formation of heme and sulfur proteins |
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| Manganese | Photosynthesis (formation of free oxygen radicals) |
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| Zinc | Protein synthesis |
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| Copper | Removing formed radicals, lignification, formation of some enzymes and proteins |
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How To Deal With Nutrient Deficiencies
Nutrient deficiency occurs due to a lack of nutrients in the soil or growing media. Furthermore, it can be due to leaching, overwatering, or pH fluctuations. Hence, knowing why your geraniums are undernourished is essential to establishing the best remedy.
Here are effective ways to deal with nutrient deficiencies and keep the leaves of your geraniums green:
- Use nutrient-rich soil or potting mix when planting your geraniums.
- Fertilize newly planted (outdoor) geraniums every two weeks throughout their growing period.
- Feed potted (indoor) geraniums every four to six weeks using a water-soluble fertilizer.
- Repot geraniums that are growing in containers when they start wilting.
Note: Apart from lacking sufficient nutrients in the soil (or growing medium), geranium leaves could turn yellow if the roots can’t absorb nutrients from the soil. To solve this issue, you can sprinkle some Epsom salt around your geraniums to boost the absorption of nutrients like nitrogen and phosphorus.
4. Protect Your Geraniums From Pests and Diseases
The foliage will maintain its green coloring if you’re feeding and watering your geraniums properly. However, these flowering plants are susceptible to diseases that might cause leaf discoloration (among other effects).
Therefore, it would help if you knew what diseases affect geranium leaves, their causes, and how to identify and treat them.
These diseases include the following:
| Disease | Cause/Pathogen | Symptoms | Remedy/Prevention |
| Southern bacterial wilt | Ralstonia solanacearum |
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| Leaf rust | Puccinia pelargonii-zonalis |
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| Bacterial blight | Xanthomonas campestris pv. pelargonii |
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| Oedema | Water imbalance |
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| Pseudomonas leaf spot | Pseudomonas cichorii |
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| Botrytis blight | Botrytis cinerea |
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| Alternaria leaf spot | Alternaria alternata |
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| Viral disease | Various viruses, including Cucumber Mosaic Virus (CMV), Pelargonium Flower Break Virus (PFBV), Impatiens Necrotic Spot Virus (INSV) |
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5. Meet Your Geraniums’ Sunlight Requirements
Geraniums are sun-loving plants. These attractive flowering plants thrive and will be evergreen if you meet their sunlight needs. Therefore, the leaves might start yellowing if your geraniums aren’t obtaining enough sunlight.
Your geraniums will require four to six hours of sunlight daily to grow healthy and bloom in time. So, if you’ve planted your geraniums indoors, ensure that you place them at a location where they’ll access adequate sunlight—preferably the morning sun.
Therefore, shift them to a shaded, well-ventilated space from noon.
However, if you’re growing these flowering plants outdoors, they’ll love to grow in full sun and can even survive a heat wave. However, geraniums will need some shade when the temperatures are extremely high, especially on summer afternoons.
6. Protect Your Geraniums From Cold Snaps
Temperature significantly affects geraniums’ growth and development, especially when it comes to the following key processes:
- Photosynthesis
- Respiration
- Formation of flowers
Since they’re native to South Africa, geraniums love warm weather. In the US, they grow well in USDA plant hardiness zones 9 to 12, and their leaves remain green at optimum temperatures.
Geraniums planted in regions whose temperatures don’t drop below freezing point can grow as perennials (all year round). However, those in areas experiencing harsh winter weather will only grow as annuals.
Therefore, annual geraniums will not withstand extended periods of wet and cool weather, and even a light freeze can be detrimental to their survival.
Generally, geraniums growing indoors need a temperature range of 65 – 70°F (18 – 21°C) during the day and 55°F (13°C ) at night. On the other hand, outdoor geraniums can withstand daytime temperatures of about 65 – 75°F (18 – 24°C) and nighttime temperatures of 50 – 60°F (10 – 16°C).
Exposing your geraniums to temperatures below 50°F for an extended period will result in stunted growth and delayed maturity. So, the leaves might start yellowing or showing reddish discolorations.
Outdoor geraniums are also vulnerable to frost damage, especially in early spring. Hence, you can protect them from the harsh weather by taking a few extra steps:
- Bringing them indoors and placing them in a dry space.
- Insulating them using cloches (bell jars), bedsheets (or blankets), and frost cloths.
- Watering your geraniums the night before spring frost.
It would help if you were up-to-date with your region’s weather forecast to predict when you’ll expect the first frost.
On the other hand, potted geraniums are more susceptible to cold snaps since their roots are shallower than in garden plants. Hence, they lose heat to the atmosphere when placed in a cold environment.
To protect your indoor (potted) geraniums, take care to follow these tips:
- Keep them away from the windows to prevent any exposure to cold drafts.
- Avoid placing them near AC vents.
7. Avoid Using Herbicides on Your Geraniums
Weeds are a nuisance to many farmers since they deprive plants of essential nutrients. Moreover, they’re invasive and aren’t a pleasant sight when they encroach on your garden or landscape. Therefore, most people reach for herbicides to control weeds.
If you’ve planted geraniums, you might need to use some herbicides to control weed infestation in your garden. Most herbicides will not harm your geraniums and will only kill the weeds.
However, this doesn’t mean there won’t be any side effects. In most cases, herbicides will injure your geraniums. The most common impact of herbicides on geraniums is the bleaching effect on the foliage. Therefore, the leaves will start yellowing or appearing pale.
So, it would help if you minimized herbicide use on your geraniums and used alternative weed control methods:
- Remove the weeds manually (and frequently)
- Mulch your geraniums to discourage the growth of invasive plants
Final Thoughts
Geraniums are drought-resistant and will thrive in warm weather. Furthermore, they maintain their evergreen foliage when grown in optimum conditions. Unfortunately, some factors cause yellowing and leaf discoloration, including diseases, water imbalance, and cold snaps.
Hence, it’s important to adopt strategies to keep the leaves of your geraniums green throughout their growing season. These include:
- Watering them properly.
- Feeding them correctly.
- Protecting them from diseases.
- Meeting their sunlight requirements.
- Protecting them from cold snaps.
- Minimizing herbicide use.
