How to Plant, Grow, and Care for Geraniums

Brightly-colored in shades ranging from common pinks and reds through deep dusky blues and violets, geraniums are a common sight in most gardens today.

The term “geranium” itself is a bit misleading, because there’s actually two separate genuses that are considered geraniums. But we’ll go into that in more detail shortly!

Whether you are simply looking for a perennial that can create a plethora of bright and wildly-colored flowers or one that smells like cinnamon or spices, you can find a geranium that will suit you. Let’s explore this aromatic and beautiful perennial in detail!

What are Geraniums?

There are two types of herbs that are called geraniums: true geraniums, which are part of the Geranium genus, and those in the Pelargonium genus. Both are part of the Geraniaceae family, and are related if not identical. Both of are often confused for one another.

The majority of what gardeners consider to be geraniums are actually Pelargonium genus plants. True Geraniums are often referred to as crane’s bill or wild geraniums, and sometimes as hardy geraniums as they’re a bit more cold-resistant. We’ll cover a bit of both here!

Native Area

While geraniums are native to most of the world, pelargonium has its origins in South East Africa, Australia, the Middle East (Turkey in particular), and parts of South Asia. There are many hybrids available now that have been developed in various parts of the world, and these are the more popular varieties sporting bigger and brighter blooms as well as being pest- and disease-resistant.

Varieties

The majority grown in the average garden bed are going to fall into the pelargonium category, simply because that’s the category that has become most known as geranium. But we’ll cover a few true geraniums as well.

Here’s a short list of some of the different types. Between the two categories, there’s nearly 700 types, but we’ll list some of the most popular!

Pelargonium x hortorum

Garden geranium, zonal geranium, malva, and malvon are the most common geranium type found at your local garden center. They create large clumps of pink, red, or white flowers atop a tall stem that rises above its fan-shaped leaves. A hybrid, Pelargonium x hortorum is a cross between Pelargonium zonale and Pelargonium inquinans.

Pelargonium peltatum

Commonly known as ivy geranium, ivy-leaf geranium, and cascading geranium. Fleshy, rounded leaves create a base from which stems rise, each holding eight to nine pink or streaked pink flowers in a clump. The ivy geranium is a popular variety, especially in areas prone to wildfires, as it tends to be less flammable than other flowering types.

The flowers tend to have five petals, some varieties streaked from the center of the flower up along the petals. Ivy geraniums tend to be more susceptible to some forms of disease, but can make for beautiful garden specimens.

Pelargonium graveolens

Scented-leaf geranium, stork’s bill, rose geranium, and sweet-scented geranium, are the common names for Pelargonium graveolens. This species is known for the rose-like aroma which its leaves produce. Velvety and soft, the leaves themselves are coated in fine downy ‘hairs’ that helps hold their scent.

The flowers tend to bloom, with the upper two petals being much more dramatic than the lower three, almost reminiscent of some forms of pansy. However, it is the scent thatcontinues to draw people back, and Pelargonium graveolens var. graveolens is heavily used in the perfume industry.

Pelargonium domesticum

Martha Washington geranium, regal geranium, and show geranium are bushy evergreens that make up another large segment of the American market’s geranium supply. Popularized here by the varieties known as ‘Martha Washington’, they are heavily flowering specimens that create large and attractive border varieties.

However, not all Pelargonium domesticum are large. There are some very attractive miniature-type geraniums in this category as well. Their main popularity stems from the heavy production of flowers they produce each year.

Pelargonium crispum

Angel geranium’, sometimes referred to as pansy-faced geraniums in the United States, tends to be a popular bicolored species. Similar in growth habits to Pelargonium domesticum, Pelargonium crispum has been bred to become more bushy and compact with smaller flowers.

Some cultivars may have a citrus-like scent to their leaves. They can be cultivated to produce an oil that is used for perfuming.

Other Scented Pelargoniums

There’s a huge selection of scented pelargonium species, all of which are grown heavily for perfuming purposes. Scents range from almond and apple through mints, citrus scents, nuts such as hazelnut, spices like cinnamon or nutmeg, and even celery.

While there’s simply too many species to mention that fall into the scented category, these can be extremely popular amongst growers for those unique aromas.

Geranium phaeum

Dusky crane’s bill, mourning widow, and black widow are some of the common names for Geranium phaeum. Native to Europe, the dusky crane’s bill has a deep violet flower with a protruding stamen cluster emerging from petals that are turned back. This gives it a bill-like look, leading to its name.

Popular varieties of this species include ‘Lily Lovell’ and ‘Samobor’, both of which are commonly cultivated in European gardens.

Geranium maculatum

Common names for this variety include wild geranium, wood geranium, spotted geranium, spotted Cranesbill, and old maid’s nightcap.

This wild plant has its origins in and around the plains regions of the United States, but has been successfully cultivated in gardens as well. Its roots are used in herbal medicine, especially among tribal groups.

One popular variety that has won the Award of Garden Merit from the Royal Horticultural Society is the ‘Elizabeth Ann’ cultivar.

Geranium pratense

Meadow cranesbill, meadow crane’s-bill, and meadow geranium are just some of the common names for this variety.

With varieties such as ‘Mrs Kendall Clark’ having received the RHS Award of Garden Merit, the meadow cranesbill is another popular geranium variety. Native to Europe and Asia, it is widely cultivated worldwide.

This species is extremely cold-hardy and can tolerate temperatures that dip into the single-digit negatives. That makes it much more popular as a garden herb in the snowier regions of the world.

Planting

To plant geraniums, select a pot or garden bed with well-draining, rich, and loose soil. Dig a hole about eight inches deep and six to twelve inches apart to allow proper root growth and airflow. Place the geranium in the hole so the top of the root ball is level with the soil surface. Backfill with soil, gently pressing it down to remove air pockets. Water thoroughly and position in a sunny location.

If planting in a container, ensure it is at least eight to twelve inches wide for each geranium.

How to Grow

Overall, geraniums are pretty easy to care for. Most of your work will be comprised of deadheading hundreds of spent flowers to encourage more blossoming. The tips below will show you the best conditions for it to thrive in.

Light

Geraniums are typically a full-sun type in most conditions. They require lots of light to create all of their vibrant flowers! However, they’re surprisingly adaptable and can be in partially-sunny conditions. For best flower production, aim for six to seven hours of sunlight per day. Most geraniums are quite tolerant of warm weather, but in desert climates, shade during the hottest part of the day is recommended.

If growing your geranium indoors, aim for six to seven hours of sunlight per day and supplement with a grow light if needed.

Water

All plants require water, but geraniums tend to be especially sensitive to over-watering and under-watering conditions. If the soil is right, they’re not difficult to maintain.

Water your geraniums only when the soil is dry to the touch. Just stick your finger into the soil a few inches, and if it seems a bit on the dry side, go ahead and water. If you find moisture about an inch below the surface, wait a little longer before watering.

Outdoor geraniums usually have a minimum of one deep watering weekly, but may require more watering during the hot summer months.

Geraniums in pots (both indoor and outdoor) should be given a deep watering once the soil has dried out. Allow the water to flow through all the soil until it comes out the bottom of the pot, then stop.

Hanging pots or outdoor ones may require more frequent watering, so be sure to check these regularly. Indoor geraniums often require less watering than outdoor ones but will need more watering if the humidity level indoors is low or during the hotter months.

Soil

There’s no doubt that geraniums like a drier soil. Don’t use bark-based or coconut coir-based soil as it generally holds too much water around the roots.

I recommend a blend of equal parts potting soil, compost, and perlite for your geraniums. This ensures that there’s plenty of perlite there to provide airflow in the soil and keep it from being too soggy. If you’re lacking potting soil, don’t panic! You can make a potting mix out of equal parts garden soil, peat moss, and perlite, and then use that to blend your geranium soil.

In addition, most geraniums prefer an acidic pH level. Something in the 5.5 range will make your geraniums quite happy.

Temperature

When the weather’s over 90°F (32°C), try to ensure they get a nice break from the scorching sun. Ideal growing conditions for indoor plants are 65-70°F (18-21°C) temperatures, but they’ll accept up to 85°F (29°C) without any significant slowing of growth.

Fertilizer

A good, balanced fertilizer is what’s recommended by most geranium societies, applied every four to six weeks. If you’d like to fertilize more often, make a half-strength dilution of your fertilizer and fertilize every two to three weeks.

Trying to encourage heavy flowering? You can switch to a high-phosphorous fertilizer and add fresh compost over the surface of the soil each fertilization. The compost provides additional nutrition, but that extra phosphorous encourages the plant to flower rapidly.

Maintenance

When it comes to maintaining geraniums so that they perform at their best, they need to be repotted occasionally, and they need pruning to keep their shape and not become too leggy.

Repotting

It’s surprisingly easy to repot geraniums, although older ones require a bit of pruning first. Begin by preparing your growing medium. I recommend a mix of potting soil, compost, and perlite to ensure it’s well-draining and nutrient-dense. Moisten it slightly, just enough to make it damp to the touch but not muddy.

Trim back the branches and stems of your geranium plant to a four-inch length, trying to be sure that you cut just above a node on the branch. It will grow back quickly!

Gently tilt the old pot and slide the geranium out. Unwind any roots that have started to circle around the rest of the root clump, and trim if necessary. If any roots show signs of rot, trim those out as well.

Set your geranium into its new pot at about the same height it was planted before. Hold it in place with one hand, and fill around it with fresh growing medium. Then, give it a good watering, being sure that you water until you have water freely flowing out the base of the new pot.

Be sure to place a couple inches of mulch on top of the soil to slow down water evaporation, and water when the soil beneath the mulch feels dry.

Pruning

Half of your pruning for your geraniums will be spend deadheading spent flowers. It seems like a never ending task, but to encourage more flowering, you should absolutely do it!

To deadhead flowers, look at the stem beneath the flower, and trim back to just above a leaf node. That way, it will produce new growth at that node area and continue to blossom.

In late summer or into the fall, once it has begun to die back, it’s time to prune perennial geraniums. Trim the plant to two to three inches above the soil’s surface. Whenever possible, cut just above a leaf node to encourage future growth, but shape it down low.

Mulch around the base of the autumn-pruned geranium for winter root warmth, and it will grow back slowly during the winter and much more rapidly come springtime.

Propagation

Geraniums can be propagated from both cuttings or from seed. We all know how to sow seeds, so I won’t get into huge detail there. But geranium seeds don’t need to be planted deeply. Just enough soil to cover them is fine! They germinate best at soil temperatures of 75°F (24°C).

Cuttings can be taken year-round, but it’s best to wait until it’s not currently blooming.

To take a cutting, find a healthy stem and cut it just above a leaf node (a swollen place on the stem). Remove all but the tip leaves, and then make a second cut at the base just below a leaf node, leaving yourself with a four to six-inch long cutting.

Place your cutting into a sterile container of warm, damp potting soil. Water it thoroughly, then place it in a bright location, but not in direct sunlight. You do not have to cover geranium cuttings, as that can cause them to rot. Water when the soil dries out, and it should take root within a couple weeks.

Common Problems

There’s quite a few pests that geraniums have to contend with, as well as a number of diseases. While you’re not likely to experience these problems constantly, here’s how to handle them if and when you do!

Growing Problems

Geraniums are warmth-loving. If the weather gets too cold, the leaves can turn yellow or red, wilt, and eventually die. To prevent these problems, be sure your geranium is kept warm during the winter. If the temperature is under 50°F (10°C), consider using a cold frame or move to a greenhouse or indoors.

Oedema, also known as edema or corky scab, is another problem that primarily affects ivy geraniums. When the air is cooler than the soil temperature, but humidity both in the soil and air is high, it can cause edema.

This condition creates watery blisters on leaves that rupture and turn yellow or brown and can be mistaken for forms of rust. To prevent oedema, keep the air humidity low and don’t overwater. Air temperature should be kept at or above the soil temperature as well.

Improper irrigation is a regular issue for geraniums. Overwatering can cause leaf yellowing, but so can underwatering. Check the soil and reduce your watering frequency if needed.

Underwatering can cause reddening of leaves or crisped edges of leaves. Again, check the soil, and if it’s dry, water.

Some nutrient disorders or deficiencies may also cause reddening or yellowing of leaves, but checking your irrigation status first is usually the best choice. If your irrigation level is good, then move on to having the soil analyzed and checking for signs of disease.

Pests

There are a number of sucking-type pests that go after geraniums for their inner juices.

The common ones include aphids, scale insects, mealybugs (the citrus mealybug and Mexican mealybug), spider mites, thrips, and whiteflies.

There are a couple things you can do to conquer all of these pests. Spray your geraniums regularly with neem oil to keep them at bay and to smother their eggs. Release ladybugs and lacewings around your garden during spring and summer to help kill them off.

Other pests include armyworms, particularly the beet armyworm, bollworm (near cotton farms), cabbage loopers, geranium or tobacco budworm, geranium plume moth, the oblique-banded leafroller, omnivorous leaftier (sometimes called strawberry fruitworm), and the variegated cutworm.

Like the sucking insects, there’s one primary control method that I recommend for all of these. Spraying or powdering your plants with Bacillus thuringiensis, also known as BT spray, will eradicate a couple hundred species of caterpillars.

Look out for the fuller rose beetle, aka the rose weevil, and attract beneficial nematodes in the soil that will also attack the weevils, as will parasitic wasps.

At the end of this long pest list, we have the sciarid fly, known as the dark-winged fungus gnat.

Using the common household version of hydrogen peroxide as a soil drench is quite effective at killing the larvae of fungus gnats, as is neem oil.

Diseases

There are quite a few diseases that can infect geraniums, and many you will never see. But to be comprehensive, we cover most of them.,

Fungal Infections

Fungal issues like Armillaria root rot, botrytis blight, alternaria leaf spot, and other leaf spots, pelargonium wilt, and verticillium wilt are common problems for geraniums.

Geranium rust, also known as pelargonium rust, causes yellow spotting with dark brown pustules filled with fungal spores. Neem oil can help protect the foliage from developing this disease.

Geraniums showing the symptoms of verticillium wilt should be removed completely and destroyed.

Bacterial Infections

Bacterial infections in geraniums tend to be incurable. Prevention is your best defense.

Bacterial leaf spot or bacterial blight are some of the most common diseases. Most bacterial leaf spots and blights are spread by water splashing onto leaves or through infected soil. Destroy infected plants.

Blackleg is a common infection for geraniums which turns the stems a distinctive black color and causes them to wilt, as well as causing root rot. Plants infected with blackleg will not recover and should be destroyed.

A pair of gall types also tend to strike geraniums.

Leafy gall and crown gall are transmitted through the soil, and infected plants should be destroyed. Avoid planting new geraniums in that spot.

Viruses

There is also a long list of viral diseases which can affect geraniums. Like the bacterial diseases, these have no known remedy. Infected plants should be destroyed to prevent viral spread.

Two types of mosaic virus, the cucumber mosaic virus and tobacco mosaic virus, can spread via aphids, virally-infected seed, or via human hand on tools. 

Curly top, also referred to as beet curly top virus, causes thickening of the leaves, as well as twisting and deformation.

Also, look for impatiens necrotic spot virus and tomato spotted wilt viruses that cause a wide variety of symptoms, including yellowing, spotting, discoloration, stunting, wilting, and stem death, among others.

Pelargonium flower break causes stippled yellowing of leaves, leaf edge browning, and yellow veining. This disease is widespread in greenhouse environments.

Finally, there is the tobacco ringspot virus. Transmitted by everything from nematodes to honeybees, this virus causes irregular yellow splotches on leaves, crook-shaped stems with drooping flower heads, browning and rolling of leaves, and other symptoms.

Most of these viruses are transmitted by pest populations. If you keep them free of pests, you will greatly reduce your chances of developing these viral infections. Destroy any that are infected to prevent the spread of the disease.

Frequently Asked Questions