Versatile and vibrant, geraniums are a familiar sight in gardens all throughout summer. Their combination of bright blooms, decorative foliage, and delicious aromas, coupled with a long flowering period and low-maintenance care requirements make geraniums one of the most popular bedding plants and container plants for gardens, patios, and balconies the world over.
But what’s the difference between geraniums and pelargoniums? How many types of geranium are there? And what’s the best way to grow them? This guide will teach you everything you need to know about gorgeous geraniums and how to grow them.
What are geraniums?
The Geraniaceae family of herbaceous flowering plants encompasses several genera of annual, biennial, and perennial flowering plants. Most geranium species feature flowers made up of five petals, often adorned with distinct vein-like patterns and usually vivid white, pink, orange, red, purple, or blue coloured.
Geraniums are prized not just for their blooms, but also for their ornate foliage. Many species have variegated leaves with enticing red tinges or leaves with delicately scalloped edges. Some other species of geranium have beautifully scented foliage which is often edible! Different geraniums have different growth habits, some trail or cascade, whilst others grow upright and shrub-like.
Geranium vs Pelargonium – what’s the difference?
Confusingly, two distinct plants are both known by the common name ‘geranium’. Cranesbill, (so named because their seed pods resemble the beak of a crane bird), or hardy geraniums, are the ‘true’ geraniums of the family, with over 400 different species united under the Geranium genus.
Additionally, Pelargoniums, a closely related genus of the Geraniaceae family consisting of around 280 species, are also colloquially known as geraniums. Similar to geraniums, pelargoniums take their name from the Greek pelargós, meaning ‘stork’, because the seed pods resemble the beak of the stork birds.
The confusion over the nomenclature of each came about in the eighteenth century when both pelargoniums and geraniums were mistakenly thought to belong to the same geranium genus and were classified as such.
It wasn’t until 1789 that geraniums and pelargoniums were reexamined and recognised as distinct yet related plants, and were finally classified as belonging to separate genera. This early misunderstanding and the resulting misnomer, however, endures to this day.
One of the easiest ways to tell the difference between a true geranium and a pelargonium is to look at the symmetry of the flowers. Both types of geraniums have five-petaled blooms, but hardy geraniums will have radially symmetrical petals, whilst pelargoniums will have two top petals which differ slightly from the bottom three petals.
Most, but not all true geraniums are frost hardy, hence the name, ‘hardy’ geraniums, and originate from temperate regions of the Mediterranean. Generally speaking, pelargoniums, which hail from the warm and humid climate of South Africa, are tender annuals that are not frost-hardy.
What do geraniums symbolise?
When we think of geraniums, we often imagine bright and cheerful lollipop-like flowers standing proudly atop lush lime green foliage, so it’s no surprise that geraniums are thought to symbolise happiness, cheer, and positivity. They are also associated with friendship and are traditionally given as housewarming gifts since pelargoniums are well suited to being grown indoors.
In their native South Africa, indigenous tribes believe the roots of geraniums to possess healing qualities, and they are frequently used to treat respiratory ailments. In other cultures, the essential oils extracted from the foliage of scented geraniums are used to help treat and alleviate symptoms of depression.
Geraniums haven’t always been thought of in a positive light, however. In Victorian Britain, they were often associated with foolishness, folly, or melancholy!
Types of Geraniums
There are six main groups of geraniums, which are generally distinguished by their growth habits, foliage style, and flowers. Let’s take a closer look at each of the main geranium groups and their characteristics.
Cranesbill or Hardy geraniums are the only ‘true’ geraniums. Unlike pelargoniums, true geraniums are frost-hardy and can be safely left outdoors over winter. Their flowers are generally wide, open, and saucer-like, and come in a range of white, blue, lilac, lavender, and fuchsia hues, often with delicate deep-coloured vein-like patterns on the petals.
They tend to have less interesting foliage and aren’t scented like some pelargoniums. Hardy geraniums have a more compact growth habit, often only reaching around 60 centimetres in height, whilst pelargoniums can often reach double this height.
Zonal geraniums are probably the most widely planted variety of pelargonium. They take their name from the darker ‘zones’ of colour which decorate the central portion of their intricate single, double, and semi-double flowers. Their colours range from whites to peaches, to deep reds.
Zonal geraniums have been bred to be sterile, meaning they don’t produce seeds and all of their energy can be directed toward their beautiful blooms. This means they can only be propagated and grown from cuttings. Zonal geraniums are often categorised as being ‘fancy-leaf’ varieties since their foliage is often variegated and adorned with ombre red or rust-coloured markings.
They are some of the toughest and most drought-tolerant pelargoniums, so are well suited to warm, dry climates. Zonal pelargoniums have upright, compact growth habits, perfect for pots, containers, and petite gardens.
Regal, or Martha Washington geraniums are annual pelargoniums with stunning trumpet-shaped, bi-coloured, single or double flowers which range in colour from whites and pale pinks to deep indigos and burgundies. Their foliage is soft and velvety to the touch, often with a pleasant, subtle scent.
Regal geraniums are often categorised as ‘fancy leaf’ geraniums, since they have highly decorative foliage, with intricate variation patterns or spiral markings. Regal geraniums are the showiest of all pelargonium varieties and can hold their own in even the boldest of borders.
They also bloom the earliest of all varieties, making their presence known well before many other bedding plants. They are more shade tolerant than other varieties, so are a great way to add drama to dimmer corners of the garden.
Scented geraniums are pelargoniums that are grown more for their aromatic foliage than their blooms, as their flowers tend to be smaller and more restrained than other varieties. Their leaves have tiny glands which release scented oils to help them stay cool during the hot summer months, and these oils are often extracted for use in cosmetics, fragrances, and essential oils.
They offer a huge variety of different aromas, ranging from fresh and fruity to crisp and minty, to floral and musky, to sweet and chocolatey, depending on the species. Crushing the leaves releases a stronger smell, and the leaves are edible, making scented geraniums a stunning addition to kitchen and herb gardens.
Many of the citrus-scented varieties are planted in terraces and patios as a natural insect repellant since they release a smell similar to citronella. If you’re looking for a functional, practical, and versatile geranium, then look no further than the scented varieties.
Ivy geraniums are distinguished by their trailing growth habits. Their leaves are similar in shape and thickness to the foliage of their namesake, ivy. Like zonal and regal varieties, some types of ivy geranium can also be classified as ‘fancy leaf’. These pelargoniums are perfectly suited to hanging baskets, where their foliage and flowers cascade elegantly downwards as long as five feet, making for a stunning summer display.
Their blooms can be a wide variety of colours, from whites to purples, to oranges, to reds. Ivy geranium flowers are more delicate and muted than other varieties, although several varieties are self-cleaning, meaning they automatically drop fading flowers and don’t require any deadheading. Ivy varieties are also fairly shade tolerant, so are more flexible in their positioning than other varieties.
Interspecific geraniums are created through hybridisation or cross-breeding of the zonal and ivy varieties, meaning they exhibit the best features of each. Interspecific geraniums exist only through human intervention and are not found anywhere in the wild. By combining the stunning, bold flowers of zonal varieties with the elegant and versatile growth habits of ivy geraniums, breeders have created a true summer showstopper, perfect for baskets or ground cover.
How to grow geraniums from seed
Geraniums are readily available from most garden centres and nurseries as semi-mature plug plants, however, when growing them in volume as bedding plants, it’s much more cost-effective to grow them from seed. Seed-grown geraniums also tend to produce more bountiful blooms than those grown from cuttings.
Geraniums are fairly easy to grow from seed, although they are slow to mature, so require a little patience. Seeds should be sown indoors in early February, and flowering usually occurs 12 to 15 weeks after sowing.
Geranium seedlings are prone to damping off, a fatal disease caused by fungal spores, so it’s crucial to use a sterile seedling substrate and a seed tray with plenty of drainage holes when sowing your geranium seeds.
Fill the seed tray with your sterile soil, and give it a thorough watering before distributing the seeds across the soil evenly. Cover the seeds with a very fine layer of soil. This top layer is more for protection than anything else since geraniums need plenty of light to germinate.
To maintain consistent moisture levels for germination, you should cover your seed tray with a plastic lid or a clear plastic bag. Position the tray somewhere with plenty of bright, indirect light and a consistent temperature of around 21°C.
Seedlings should appear in around ten to twenty days, at which point you should remove the plastic covering and place the seedlings under fluorescent lights or on a very sunny, south-facing windowsill, keeping the soil lightly and evenly moist.
Once the first true leaves appear, the seedlings can be transferred to individual pots filled with fertile potting mix and kept under bright light. You can add a little fertiliser at this point to give your geraniums a head start, but dilute it to a quarter strength. Continue watering your juvenile geraniums whenever their soil feels dry to the touch.
Once the first frost has passed, you can begin hardening off your geraniums over the course of a week or two, allowing them to acclimatise to outside temperatures. Early blooming varieties will begin to bud as soon as May.
How to grow geraniums from cuttings
Propagation from cuttings is the quickest, easiest, and, in the case of zonal varieties, the only way to grow geraniums. Cuttings from pelargoniums can be taken at any time of year, since they don’t have a dormant period, but they will be more successful when taken in early spring, just when they begin to grow most vigorously.
Cuttings from hardy geraniums are most viable when taken in late summer or early autumn, while the plant is still actively growing.
Snip a stem from the mother plant just below a leaf node and remove most of the foliages, leaving just enough leaves to perform photosynthesis. Opt for younger stems over older, woody stems. Place the end of the cutting in a pot with moistened, fertile potting soil, and position somewhere with plenty of bright, indirect light, and warm temperatures.
They don’t need to be covered like seeds do, as this can retain too much moisture and lead to rot. Keep the substrate moist, but not wet, and after a few weeks, roots should begin to emerge. Once roots are established, your geranium is ready to be potted up or planted out.
Position and Spacing
If your geraniums will be grown in ground borders, ensure they will receive at least six hours of direct sunlight each day. The necessary spacing will depend on your chosen variety, so always check the label. Generally, upright varieties can tolerate dense planting and can be placed closer to other plants than trailing or ivy varieties which need more room to spread.
Potted and basket-grown geraniums should be positioned in full sun to produce maximum blooms throughout summer. Make sure the container has plenty of drainage holes since they don’t like waterlogged soil.
Pelargoniums grown in containers will need to be brought inside over winter otherwise they will die when temperatures drop. Hardy geraniums grown in pots or baskets can be left outside through winter but should be repotted each spring and the potting soil refreshed to encourage healthy new growth through summer.
Soil
Geraniums are not overly fussy about soil conditions, so long as it is relatively loose and free draining. If you have heavy or clay soil, improve drainage before planting your geraniums by working through plenty of compost, organic matter, or drainage materials like perlite. Geraniums will quickly become stressed if planted in waterlogged or compacted soil. Geraniums prefer a neutral to alkaline soil pH level.
Light
Geraniums are sun-lovers and will need six hours of direct sunlight per day to ensure maximum blooms. Exposure to sunlight will need to be increased if they are in a position where they receive only dappled light. They can cope with shadier positions, but they may struggle to flower.
Water
Geraniums are fairly drought tolerant, but you should aim to water them thoroughly and deeply every three to four days. Make sure the top couple of inches of soil has dried out completely between waterings to avoid root rot. Geraniums grown in baskets or containers may need more regular watering since they tend to dry out faster.
It’s best to keep to a regular and consistent watering schedule for your geraniums, as sporadic waterings and periods of drought can lead to wilting foliage and stunted blooms.
Temperature
Both true and pelargonium geraniums are heat lovers, having originated from hot climates. In fact, until the twentieth century, almost all geraniums were grown under glass in northern Europe. Whilst hardy geraniums can withstand temperatures as low as seven degrees below freezing, pelargoniums are not frost-tolerant at all, and will begin to die back once the first frost arrives unless they are lifted and overwintered somewhere warm.
Food
Whilst geraniums are actively growing through the summer, you should aim to feed them at least monthly with a nitrogen-rich or balanced liquid fertiliser. They are not voracious feeders, however, so depending on the fertility of your soil, they can still bloom abundantly even with less regular feeds. Don’t fertilise your hardy geraniums during their dormant period over winter.
Pruning
Pelargoniums are relatively low maintenance, and won’t require any pruning in the strictest sense of the word, but fading or drooping blooms should be deadheaded periodically throughout the summer to encourage new, vigorous flowers well into early autumn.
To prevent your geraniums becomes leggy, spindly, or sparse, you should pinch back the stems regularly throughout the growing season. Pinch just above the end set of leaves or buds on each stem to encourage bushy and dense foliage.
Hardy geraniums should be cut back just after flowering, which encourages a fresh spell of late summer blooms. They can be pruned again in early spring to encourage plenty of healthy growth for the new growing season.
Overwintering
Hardy geraniums can be cut right back around the time of the first frost and left in the ground or pot outdoors over winter. They will begin to produce plenty of fresh new growth when spring arrives.
Pelargoniums will continue flowering well into autumn with the correct conditions and care but will start to die off as soon as the first frost arrives. Because pelargoniums don’t have a natural dormancy period, they can be overwintered indoors or in a heated greenhouse and treated as houseplants, but they will need a bright position on a windowsill with plenty of sunlight.
If you do plan to overwinter your pelargoniums indoors, make sure you lift them from their beds before the first frost arrives. Cut back each plant by around a third and remove any dead or faded foliage, before placing the plant into a small pot with fresh potting mix.
Whilst indoors, you should water your pelargonium very sparingly, waiting for the foliage to begin to droop slightly between waterings, and don’t fertilise them. Once spring arrives, you can gradually increase the watering schedule. Wait until the last frost has passed before hardening off, and finally, planting out in its final position for the summer.
FAQs
How long do geraniums live?
Pelargoniums will only last for one season unless they are lifted and overwintered indoors. Hardy geraniums, on the other hand, can live for many years with the correct care. Some have even been known to survive as long as forty years!
Can Geraniums be grown indoors?
Pelargoniums are versatile plants that can be grown indoors just as easily as they are grown outdoors, with the added benefit that they can remain in flower year-round when grown indoors. Hardy geraniums are better suited to being grown outdoors and won’t fare so well as houseplants.
What do Geraniums smell like?
Scented geraniums are available in an enormous array of fragrances. Each varieties foliage has its own unique scent. Some smell minty, fresh, and fruity, whilst others smell musky, floral, sweet, and even spicy!
Wrap Up
With so many varied and versatile geraniums available, it’s hard to resist having a go at growing your own. Whether you like beautiful blooms, stunning scents, or fascinating foliage, there really is a geranium to suit every home, every garden, every gardener, and every climate.
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