It can be very confusing when talking about geraniums.
This is because the term applies to both the Geranium (jer-AY-nee-um) and Pelargonium (pe-lar-GO-nee-um) genera.
These two members of the Geraniaceae family, which were separated in 1789, share many qualities but are also distinct in others.
Those from the actual genus are best known as either hardy geraniums or true geraniums.
They also go by their common name:
They come from tropical regions around the world where they grow on mountainsides, giving them a higher tolerance to cold and other harsh conditions.
Of the 422 species, most originate in the eastern Mediterranean area.
Meanwhile, pelargoniums have only 280 species and hail mainly from southern Africa.
They’re a lot less tolerant of cold and other harsh conditions, although they’re somewhat drought tolerant.
Pelargoniums, along with their many hybrids and cultivars, are far more popular than hardy geranium and have been divided into several types.
To make things even more complicated, several species of geranium were placed in a third genus, Erodium (er-OH-dee-um), which closely resemble the hardy geranium but aren’t usually associated with the term “geranium.”
But you may be surprised to learn that, despite so many different geraniums, all can technically be grown indoors as perennials.
Potted Geranium Care
Size And Growth
There’s a lot of variety in geraniums, including their size and growth habit.
Hardy geraniums generally range from 4” to 24” inches tall and wide, holding a more shrublike appearance when grown in containers.
Pelargoniums are a lot more varied, with different types having their own size rangers.
- Ivy geraniums (Pelargonium peltatum) have a trailing growth habit up to 48” inches long and heart-shaped leaves, making them a popular alternative to true ivy species.
- Regal geraniums (Pelargonium × domesticum) are hybrids designed primarily as container plants and tend to be 12” to 24” inches tall.
- Zonal geraniums (Pelargonium x hybridum) are better known as common garden geraniums and have both dwarf cultivars of 5” to 6” inches and full-sized shrubs up to 24” inches tall.
Another group is known as the “scented-leaf geranium” and includes members of the other groups with the common attribute of having leaves that give off a scent, usually when bruised or crushed.
Flowering And Fragrance
Perhaps the most notable difference between true geraniums and pelargoniums is in the flowers and fruit.
True geraniums have disc flowers with five equal-sized ray petals, while pelargoniums usually have two smaller upper ray petals and three larger lower petals.
Bloom times and frequency can vary greatly, with some only blooming once and others blooming throughout the growing season.
Geranium flowers come in a wide range of colors, including bi-color, solid, and richly veined.
Another distinction between the plants is the number of stamens or anthers, with pelargoniums having 7 stamens and true geraniums having 10.
True geraniums gained their common name because a few species have fruit shaped like a crane’s bill, while many pelargoniums have fruit shaped like stork bills.
Light And Temperature
All geraniums love the sun but can be a little sensitive to full, harsh sunlight.
A spot with bright, indirect sunlight or filtered sunlight is generally best for all indoor geraniums, although the ones grown in containers outdoors will enjoy morning or evening full sun exposure.
Normal household humidity is perfect for these plants, but it can develop fungal infections if the humidity gets too high.
Also, while these plants have specific hardiness zones for growing outdoors, they can all enjoy nearly the same indoor temperature ranges.
Aim for temperatures of 70° to 75° degrees Fahrenheit during the day and a slightly cooler 65° to 70° degrees Fahrenheit for pelargoniums and 50° to 60° degrees Fahrenheit for hardy geraniums.
Avoid temperatures below 60° degrees Fahrenheit when growing a pelargonium.
Regardless of the type you have, all geraniums dislike sudden temperature drops, so try to keep them away from drafts.
Watering And Feeding
The soak-and-dry method is perfect for all geraniums.
- Aim to water when the soil feels dry 1” inch down.
- Water slowly and thoroughly with tepid water, avoiding getting any water on the leaves until moisture begins to seep from the drainage holes.
The exact amount of food your geranium needs can vary greatly, but all indoor plants will benefit from a balanced liquid houseplant fertilizer applied according to the instructions on the package.
Soil And Transplanting
Hardy geraniums are far more tolerant of different soil types than their siblings, but all geraniums can agree that the soil needs to be well-draining.
True geraniums will want a soil pH of 5.8 to 6.3, while pelargoniums can vary greatly, with some needing a minimum of 6.0 and others needing a minimum of 6.3.
As a result, it’s best to check on the requirements for your specific type of pelargonium before choosing a soil mix.
That said, a loamy potting mix with some coarse sand or perlite will work for almost any geranium.
Repot your geranium every 2 to 3 years to give it fresh soil and divide as needed.
True geraniums need to be divided every 3 to 5 years to retain heavier blooms, but both genera can be divided in spring to avoid increasing pot size for propagation.
Grooming And Maintenance
Once established, geraniums need very little maintenance.
- Prune away any dead or diseased leaves.
- Remove the lowest branches to improve air circulation to the base of the plant.
Deadheading is entirely optional but may benefit plants that bloom in waves.
How To Propagate Geraniums
While it’s possible to propagate through stem cuttings or seeds (if you have an actual species or don’t mind getting a surprise plant), the most popular method is through division since the plants need to be divided anyway.
Check out How To Start and Propagate Geranium Plants
Geranium Pests Or Diseases
All geraniums have a degree of drought tolerance, but only hardy geraniums are tolerant of cold.
Most common houseplant pests can become an issue, although the damage is usually mild.
However, be on the lookout for thrips, which carry the mosaic virus, and fungus gnats which can be evidence of a fungal infection.
And speaking of fungal infections, this is the most common category of disease you’ll face outside of root or stem rot.
Moreover, some Geranium species or cultivars are more susceptible to specific pests or diseases, so be sure to find out your own plant’s vulnerabilities.
Hardy geraniums are non-toxic and can even be used for food and medicinal purposes, but pelargoniums are all toxic to both humans and pets, so be sure to keep them out of reach of curious mouths.
Potted Geranium Uses
Regal geraniums may take the cake when it comes to looking good in a container, but ivy geraniums will eat that cake if you put them in a hanging basket where they shine the best.
Depending on the species or cultivar, potted geraniums may be used as an outdoor plant in summer or grace entryways, or be a wonderful table or shelf display.