How to Grow Geraniums – The Ultimate Guide!

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The Geranium plant is an iconic and popular flowering plant. They have been commercially grown for over two hundred years. 

These fragrant blooms come in many shapes, sizes, and colors. They are also versatile in where they can be grown. 

Geranium plants are easily grown in containers or pots, flower beds and even hanging baskets. 

Geranium plants are scientifically known as Pelargonium hortorum. These plants originated in South Africa and made their way to France. 

From there, Geranium plants traveled over to the northern parts of America in 1786. They are now common in many parts of the world. 

Relatively easy to care for, Geraniums are rewarding plants to grow. Everything about this plant is beautiful. Their blooms are dainty and attractive with varying color combinations. 

Surrounding the clusters of blooms, Geranium plants also sport fancy-looking leaves. So, if you’re planning to bring one home, then continue reading below.

 

Care Guide for Geranium Plants

Geranium plants are fairly easy to care for when they are kept in their ideal conditions. The most important aspect is the soil that they grow in. These plants need to be planted in medium to light-weight and well-draining soils. They are sun-loving plants but require some afternoon shade protection in very sunny climates. Geraniums are not too fussy when it comes to humidity levels. They are, however, slightly more particular where temperatures are concerned. Geranium plants are not cold hardy and grow best in temperatures between 50 to 75 degrees Fahrenheit (10 to 24 degrees Celsius). The lowest temperatures of which are to be taken during the nighttime. The frequency of watering is determined by where your Geranium is grown. If it is being grown in a pot, it will require slightly more frequent watering than one that is grown in the ground. Regardless of where the Geranium plant is grown, however, they prefer their soil to be slightly moist at all times. 

 

Soil requirements 

Geranium plants are not fans of heavy soils such as clay types. They prefer soil that is loose and has good drainage properties. 

If your soil is on the heavier side, it is simple enough to lighten it up. All you need to do is to incorporate some perlite, peat, or compost. It is not recommended to use vermiculite or manure. 

With fertile soil and a medium moisture level, your Geraniums will be perfectly happy. It is also known that these plants require a soil pH level of between 5.8 and 6.3. 

If these simple requirements are met, your plant will yield its best growth. 

If your Geranium’s soil is lacking nutrients, you can incorporate other types of organic matter to improve it. 

Organic materials you could work into the soil include bark fines, compost, and rotted manure. Including these types of materials will also help to improve the soil’s drainage.

 

Light

Geranium plants enjoy their fair share of sun. But, they also love spaces that are open and well-ventilated. 

The ideal sun exposure for Geranium plants is four to six hours of full sun in the morning. And later in the day, after noontime, light shade is preferential. 

These plants should not be left exposed to the full sun on a very sunny day. 

 

Watering

Geranium plants like their soil to be kept moderately moist. To achieve this, you will need to water them quite thoroughly and deeply.

If you are growing your geraniums in the ground, it is best to allow the top layer of soil to dry slightly in between watering periods. Doing so will aid in avoiding your plant contracting root rot. 

On the other hand, Geranium plants that are grown in pots or containers need to be watered quite regularly.  This is because the soil in a pot or container is known to get warm. 

It is an absolute necessity that the pot your Geranium is planted in has drainage holes. These holes allow excess water to drain freely which helps to prevent root rot. This in turn allows you to water your plants more frequently. 

The time at which you water your Geranium plants is also important. 

The best times to water these plants are either early in the morning or later in the evening. It is not advised to water your Geranium plants the noontime and especially not when it is very hot outside. 

Over-watering is one of the most common causes of the death of these plants. 

Geranium plants would much rather go without water for a period of time than be left to sit in water-soaked soil. A sign that you are under-watering or over-watering your Geranium plant is the yellowing of its leaves. 

Although it is possible, you should always avoid allowing your Geranium plants to wilt and then reviving them. 

Continued periods of your plant wilting and your revival of it will result in your plant having a flower production that is poor. It is also possible for your Geranium leaves to drop because of this. 

 

Temperature and Humidity

Geranium plants are not very cold hardy. If they are grown outdoors, in the ground, they are often dug up early in the autumn to be over-wintered. 

If they are grown outdoors but in pots or containers, it is easy enough to relocate them.

Ideal outdoor temperatures for these plants are between 65 degrees Fahrenheit and 75 degrees Fahrenheit (18 degrees Celsius to 24 degrees Celsius) during the day. 

During the night, temperatures should preferably range between 50 degrees Fahrenheit and 60 degrees Fahrenheit (10 degrees Celsius to 15.5 degrees Celsius). 

When temperatures begin to fall to below these ideal temperatures you will need to move your Geranium plants. If your Geraniums are grown in pots or containers all you need to do is move them indoors to a warmer spot. 

If they are grown in the ground, however, it is common practice to uproot the plants and store them for the winter. 

Geranium plants are known to tolerate a range of different humidity levels. However, in regions that are very humid, rust and mildew may occur. 

These issues are nothing to be too concerned about though as they are not life-threatening to your Geranium plants. 

 

How to Over-Winter Geranium Plants

Storing plants over the colder seasons is known as over-wintering. This is done so that the plant can be planted and regrown the following growing season. 

To do this for Geranium plants is not too difficult of a task. 

You should dig your Geranium plants up before the first frost occurs in autumn. Gently knock any extra soil you’ll find off the roots. You will then need to hang your Geranium plants upside down in a cool and moist place. 

The conditions required for the location you store your plants in are a humidity level of around eighty percent. Temperatures in this spot will also need to be between 35 degrees Fahrenheit to 45 degrees Fahrenheit (1.5 degrees Celsius to 7 degrees Celsius). 

Your Geranium plants may appear as though they are starting to dry out. If this is the case, you will need to soak their roots in water. 

When the springtime comes around, you can get ready to replant your Geraniums. Make sure that the date of the last frost has passed through. 

To replant your Geranium plants, you will need to take them out of their storage place. Cut about one-half to three quarters away from their tops. Then simply, plant them outside again. 

 

Where to Plant Geranium Plants

Geranium plants will grow happily in just about any gardening zone. Although they enjoy periods of full sun exposure, in some areas this is not recommended.

In areas with very hot summers, these plants will need access to some shade. 

Geranium plants do not ask for much of an ideal growing location. All these plants need to grow happily and thrive in a spot that receives full sun in the morning. 

In the afternoon the location should get some shade. And of course, soil that is well-draining is an absolute necessity. 

Another important factor to consider when looking for a spot to plant your Geranium plants is size. If you are planning on growing more than one Geranium plant, you will need to choose a location that is adequately sized. 

When planting multiple Geranium plants together, you will need to space them appropriately. Not leaving enough space between these plants in their garden bed can be detrimental to their health. 

Planting your Geranium plants with proper spacing between them will aid in reducing the risk of disease. 

Growing your Geranium plants in a flower bed is not your only option, however! These plants can also be grown easily inside pots or containers. 

And better yet, they do not have to be grown as outdoor potted plants. Geranium plants can be grown as houseplants!

 

When to Plant Geranium Plants

As Geranium plants are not cold hardy, you should not rush into their planting season. However, waiting too long to plant your Geraniums is also not ideal. 

It is the cooler evening temperatures that encourage the budding of these plants. 

So, finding the happy medium of when to plant these beauties is the key to success. It is important that you wait until there is no longer the danger of frost. 

Once the last frost has passed and the soil reaches a temperature of 60 degrees Fahrenheit, or 15.5 degrees Celsius, it is time to plant your Geraniums. 

 

Fertilizer

These plants appreciate just a light feeding every now and then. What some people do not know or may not realize is that it is possible to feed Geranium plants too much. 

The reason this fact is not so well known is that it does not affect the plant in a seemingly negative way. 

When you fertilize Geranium plants too much or too often, their foliage will flourish. This is not what you would expect to see from a plant that is being over-fed. 

The part of the plant that is really being affected by too much fertilization is its blooms. 

Another common misconception about fertilizing Geranium plants is what type of fertilizer can or should be used. Although there are Geranium plant-specific fertilizers available for purchase, there is no rule to say you have to use them. 

The best fertilizers to use for these plants are known to be those that are water-soluble. 

For Geranium plants that are grown in pots with a soil mix that is rich in nutrients, fertilizing is only necessary every four to six weeks. And only a minimal amount is required. 

This is true for the months of spring and summer only. Some climates allow for Geranium plants to continue to grow throughout autumn and winter. 

If this is the case for your Geranium plants, feeding during this time should only be done once every eight weeks. 

In some cases, however, certain varieties of Geranium plants require a bit more food. Or, they may need more frequent feedings. 

For example, annual Geranium plants have slightly larger appetites. These plants are typically fed with a slow-release fertilizer that is applied at the time of planting. 

This is then maintained with an application of liquid fertilizer once every two weeks to twenty days. This is only done four weeks subsequent to the time of planting. 

 

Growth

Geranium plants vary in shape and size depending on the variety. Zonal Geranium plants can grow from around one to two feet tall, or 0.3 meters to 0.6 meters. 

If they have been pinched back over the season, they are likely to reach a spread of about two feet wide, or 0.6 meters. 

Ivy or trailing types of Geranium plants can grow to as long as four feet, or 1.2 meters. This is of course only possible if they are left to grow freely from window boxes or hanging baskets. 

Other Geranium plant varieties known as ‘Regal types’ can grow to two and a half feet tall, or 0.75 meters. They may also reach as far as two feet wide, or 0.6 meters!

 

Pruning Geranium Plants

Geranium plants that are planted outside annually do not need to be pruned. However, regular checks and, when necessary, deadheading will help to prevent diseases. It is also known to increase the plant’s production. 

Deadheading is a term used when pruning plants. It refers to removing old blooms off of a plant once they begin to turn brown. This is not done by simply removing just the top flowers. 

It is required that you cut the stem that sustained the flower off at the bottom. Doing so allows the plant to redirect and use the nutrients it receives more efficiently. This will effectively result in aiding the plant to produce new flowers. 

You should also remove any dry or yellowed leaves from your Geranium plants. These leaves can often be found near the base of the plant. 

Their yellowing in color is typically due to a lack of light, improper watering, or plant disease. 

Removing these leaves will not only help to keep your Geranium plants looking their best but also growing their best! Yellowed and possibly affected leaves that are left intact may result in the spread of the plant’s condition to neighboring leaves. 

Other types of Geranium plants, such as the ‘Hardy Geraniums’ may require shearing after they have bloomed. 

Although they do not require very much care once they have been established, they can get a bit unkempt. This generally occurs after the Geranium’s blooming period. 

Because it is the nature of the plant to have many wispy-type stems, deadheading can be rather difficult. Shearing the Hardy Geranium plant back to basal growth is the solution. 

Not only will it improve the plant’s look, but it will also encourage reblooming! 

Within a few weeks, these types of Geranium plants will have filled back. There is, however, an exception to this. 

The variety Geranium macrorrhizum does not need to be sheared. This type of Geranium plant is easily deadheaded. 

 

Propagation

Geranium plants are among the easier plants to grow through propagation. Propagating these plants is possible through the use of seeds, stem cuttings, as well as by division. 

However, the most popular ways to propagate Geranium plants are definitely through division or stem cuttings. 

 

Stem cuttings

These are easy to do and can be done on moist soil or even in water. Select healthy stems and plant them out. 

The best time is spring or early summer but you can do it most times of the year. The plant grows very easily from a stem cutting. 

Geranium stem cuttings root fairly easily. Adequate rooting materials include, but are not limited to, water, perlite, soil, coarse sand. 

 

Division

The plant also can also be propagated from division. After a season or two of growing, new growth will appear at the base of the plant. If this growth has its own root stem, it is easy to separate and replant. 

 

Different Varieties of the Geranium Plant

There are more than four hundred species of Geranium plants. With so many variants comes a large variety in characteristics. 

Although they all come from the same family, Geranium plants can come in many different forms. 

Characteristics of these plants that are likely to change from one species to the next include their shape and size, their height, their foliage, and even their fragrance. 

Geranium plants are divided into four main categories. These categories are Common Garden Geranium Plants, Ivy Geranium Plants, Scented-leaf Geranium Plants, and Regal Geranium Plants. 

Common Garden Geranium Plants are, as the category name suggests, the most popular types of Geraniums. This category is also known as Zonal Geranium Plants. These Geranium plants are characterized by their large, ball-shaped flowers. 

Ivy Geranium Plants are the runners up to the Common or Zonal Geraniums. The plants in this category are commonly incorrectly identified as other types of plants. 

This is due to their slightly different appearance. These Geraniums have thick and glossy green leaves. They are decorated with trailing flowers which make them perfect for hanging baskets or window boxes. 

Scented-leaf Geranium Plants are adorned for their abundant fragrances released by their foliage. Compared to other types of Geranium plants, these only produce small-sized blooms. 

Their leaves may be rounded in shape, lacy, or even serrated. Some of the scents you may experience with different scented varieties include mint, citronella, rose, and even lemon. 

Regal Geranium Plants are commonly called “Martha Washington” Geraniums. These varieties are best suited to be grown as indoor plants. 

This is because of their ability and acceptance to be overwintered. Varieties in this category tend to prefer colder temperatures too. Regal Geranium Plants produce blooms that are bi-colored. 

 

Common Problems with Geranium Plants

As with all plants, pests, and plant diseases are bound to be an annoyance or become a problem every once in a while. Geranium plants are no exception. 

However, these plants are surprisingly quite resistant to pests. Although there is still a number of insects that are a pest to this plant, a large number of possible threats tend to avoid Geranium plants. 

 

Pests

The most common insects to attack Geranium plants are aphids or plant lice, whiteflies, and caterpillars or slugs. One of the most destructive of which is the caterpillar. 

 

Caterpillars

These pests attack and damage the Geranium plant’s leaves as well as their flowers. The damage caused is generally minor, however. 

Unfortunately for some, the most effective way to get rid of caterpillar or slug pests is to remove them by hand. Although many may not agree with this method of control, it is the most effective way. 

The other option, of course, is to use a pesticide. 

When buying a pesticide, it is important that it contains Bacillus Thuricide. Bacillus Thuricide is a bacteria that occurs naturally. 

It is known to attack a caterpillar or worm’s digestive system once it has been ingested by its host. Pesticides that are based on this bacteria are safe for humans as well as pets. 

 

Budworms

The worst pests of all are budworms. Budworms are caterpillars that burrow into the buds of flowers. These pests feed off of the flower’s undeveloped petals. 

When their time comes to bloom, the petals are often seen to have holes in them or are even shredded. Most times the flowers that have been affected by budworms rot before they unfurl.

Budworms are rather difficult to control. This is because pesticides and sprays do not penetrate the buds of the flowers. 

 

Whiteflies

Whiteflies, on the other hand, are not considered to be very serious pests. They are most likely to attack Geranium plants late in the summer. 

These pests are generally only interested in the plant’s leaves. Therefore, you are likely to find them on the undersides of your Geranium’s leaves. 

Treating whiteflies is not necessary unless you are planning on overwintering that particular Geranium plant. You should never take an infested Geranium plant into your house. 

Doing so puts the rest of your houseplants at risk of becoming infected with whiteflies. 

 

Diseases

Although Geranium plants have somewhat of a resistance to pests, they are prone to contracting fungal diseases. These diseases start very readily on blooms that are spent. 

Dead flowers should be removed regularly. This is best done by snapping their stems off at the base. 

There are five diseases that most commonly affect Geranium plants.

 

Alternaria Leaf Spot

This disease can be identified as dark, circular, water-soaked spots. They are typically quite small measuring only at a quarter of an inch to half an inch in diameter.

Upon closer inspection, the individual spots can be seen to have a formation of concentric rings. The individual spots may, in some cases, be surrounded by a yellow, halo-type ring. 

The best way to treat this disease is through the application of a fungicide.  

 

Bacterial Blight

This form of blight has a few different looks. In some cases, it can be identified as round or irregular-shaped, water-soaked lesions or spots. These are commonly brown or tan in color. 

It is also possible for this blight to appear as wedge-shaped, yellow areas. These may appear along the wider part of the leaf’s margin. The point of the yellowed wedge touches the leaf’s vein. 

In severe cases where the blight has been left untreated, it may result in the wilting, stem rotting, and the death of the plant. 

Unfortunately, infected Geranium plants will need to be discarded. After this, sanitation of anything that may have come into contact with the affected plant will need to be done. 

 

Botrytis Blight

Botrytis Blight is commonly known as gray mold. This disease is most active or common during periods of cool and damp weather. Typically, the first part of the Geranium plant to be affected by this mold is its flower. 

The disease will cause the blossom to turn brown and initially appear as if it is water-soaked. Following this, there may be a transition where it becomes covered by a coating of fungus spores. These fungus spores are seen as gray in color. 

These diseased blossoms will fall off prematurely. Any leaves that the affected petals come into contact with along the way down will also develop lesions or spots. 

The best way to go about dealing with this disease is to prune away infected parts of the plant and destroy them. The soil around your plant should also be kept clean and clear of debris. 

If you happen to catch the disease in its early stages, fungicides can be used in order to help control further spread. 

 

Pelargonium Rust

Rust fungus is a fairly easy disease to identify as opposed to blight or leaf spot diseases that can become difficult to distinguish between one and another. 

When a Geranium plant is infected with Pelargonium Rust, pustules can be seen developing on the underside of the plant’s leaves. The pustules are reddish-brown in color. 

Directly above them, on the upper side of the leaves, yellow areas will form. 

Geranium plants that are afflicted with this rust fungus are best treated through the application of fungicides. The infected leaves should also be removed from the plant. 

 

Blackleg

This is a disease that affects young Geranium plants or cuttings. It is a very distinct disease and is practically unmistakable. This disease causes the Geranium’s stem to rot. 

The Geranium plant’s stem starts out resembling a brown-colored water-soaked rot. This occurs at the stem’s base. The affected area then turns to a black color and begins to spread up the plant’s stem. 

Following this results in the plant’s rapid demise. If a cutting becomes infected with the blackleg disease, it must immediately be removed and then destroyed. 

There are precautions that can be taken in order to avoid Geranium plants becoming affected by this type of disease. 

One of the most important precautions that should be taken is to use rooting media that is sterile. Garden tools that are being used to take the stem cuttings should also be disinfected before and after use. 

Damp environments are known to foster this disease and should therefore be avoided. This is also inclusive of dampness as a result of overwatering the stem cutting. 

 

Frequently asked questions about how to grow geraniums

 

What plants grow well with Geranium plants?

Geraniums make for great companion plants. This is due to their natural ability to repel many different insects and pests. They are the ideal plants to grow alongside those that are typically targeted by pests. Crops such as cabbage, corn, and grapes are especially common. Aside from that, traditionally, Geranium plants were paired up as companion plants for roses. 

 

Are Geranium plants perennials or annuals?

Geranium plants are considered to be annual growers throughout most of the world. The exception is for the warmer parts of Northern America. However, it is possible and commonly practiced, to force these plants into growing as perennials. This is done by over-wintering the Geranium plants. 

 

Conclusion

There are so many Geranium plant varieties available. There is bound to be one to suit every person’s preferences. 

Better yet, if you are an all-out plant enthusiast, you can collect all your favorites! 

What is also fantastic about these plants is that they can be grown just about anywhere. Whether you have a spot in your flower bed, or a new pot, or even a lonely hanging basket Geraniums will grow quite happily!

Geraniums are not plants that should be feared by beginner gardeners either. With the right care, these plants will be a rewarding addition to any gardener’s collection, home, or garden.