Pelargonium is a genus of flowering plants that includes about 280 species of perennials, succulents, and shrubs, commonly called geraniums, pelargoniums, or storksbills. Geranium is also the botanical name and common name of a separate genus of related plants, also known as cranesbills. Both genera belong to the family Geraniaceae. Carl Linnaeus originally included all the species in one genus, Geranium, and they were later separated into two genera by Charles Louis L'Héritier de Brutelle in 1789. While Geranium species are mostly temperate herbaceous plants, dying down in winter, Pelargonium species are evergreen perennials indigenous to warm temperate and tropical regions of the world, with many species in southern Africa. They are drought and heat tolerant, but can tolerate only minor frosts. Some species are extremely popular garden plants, grown as houseplants and bedding plants in temperate regions.
Pelargonium occurs in a large number of growth forms, including herbaceous annuals, shrubs, subshrubs, stem succulents and geophytes. The erect stems bear five-petaled flowers in umbel-like clusters, which are occasionally branched. Because not all flowers appear simultaneously, but open from the centre outwards, this is a form of inflorescence is referred to as pseudoumbels. The flower has a single symmetry plane (zygomorphic), which distinguishes it from the Geranium flower, which has radial symmetry (actinomorphic). Thus the lower three (anterior) petals are differentiated from the upper two (posterior) petals. There are five stigmata in the style. Leaves are usually alternate, and palmately lobed or pinnate, often on long stalks, and sometimes with light or dark patterns. The leaves of Pelargonium peltatum (Ivy-leaved Geranium), have a thick cuticle better adapting them for drought tolerance.
Table of Contents
4 - 48 inches
6 - 36 inches
6.0 - 6.5
Growth Nutrition of Geranium
The recommendation for constant feed fertilizing of geraniums is generally 200 to 250 ppm of nitrogen. Experience suggests nutrient problems are minimized when a constant fertilizer program is used. Fertilizer types: 15-15-15 (Geranium Special), 15-16-17 Peat-lite, and 20-10-20 Peat-lite.
Types of Geranium
Zonal geraniums are the most common type of geranium, with sturdy flower stems topped with balls of blooms. The name comes from patterns on leaves that deepen as a leaf matures. Zonal geraniums open flowers in a rainbow of hues, including red, pink, peach, white and bicolor blends.
A seed geranium is the near-twin of a zonal geranium. Probably the easiest way to tell them apart is by how they're sold. Seed geraniums usually cost less and are sold in packs or flats. The plants are also usually smaller overall than a zonal geranium, which costs more and is typically sold in individual pots. Seed geraniums are ideal for filling planting beds. Flowers open in a wide range of colors.
Martha Washington Geranium
Martha Washington geraniums, also known as regal geraniums, have showy flowers with velvety petals in shades including burgundy, pink, white and bicolor blends. Martha Washington geraniums are a cool-season bloomer that's usually available in early spring. It's a favorite gift plant for spring holidays like Easter and Mother's Day. Once flowers fade, it's tough to get more blooms, except in regions with cool summers.
If you want a geranium hanging basket, look for an ivy geranium. This geranium naturally grows in a trailing form. It's a perfect choice for hanging baskets and window boxes. Flowers open in a range of colors, including lavender, pink, burgundy, white and bicolor blends.
Variegated geraniums up the geranium game by adding multicolored leaves to the plant. This is a type of zonal geranium that grows strongly upright — as tall as 3 feet. Leaves are often green and white, but can also have a trio of shades like cream, green and bronze. They look fantastic in containers, where you can see the colorful leaves close up.
Interspecific Hybrid Geranium
When you cross a zonal geranium with an ivy geranium, the result is called an interspecific hybrid geranium. It's like getting the best of both worlds in one plant: big, nonstop flowers on a plant with a full and mounding or slightly trailing growth pattern. These geraniums have great heat tolerance (even Texas heat) and fill planting beds and containers with strong color. Two common varieties are Calliope and Calliente.
Angel geraniums (Pelargonium x), a cross of P. crispum and regal geranium, produce flowers with striking patterns in shades of pink, purple, mauve, or white. Mid-green leaves are rounded, crinkled, and sometimes scented. Plants have a bushier habit and range from 9 to 36 inches in height.
Bette Shellard Geranium
It displays tricolor leaves in cream, green, pink hues, and scalloped edges. For best colors, keep it at a spot that gets sunlight for 3-4 hours.
Miss Farren Geranium
‘Miss Farren’ offers round leaves with toothed creamy-white edges that match perfectly with the dark green center.
Scented geraniums release amazing aromas when you brush or rub their leaves. Fragrances include lemon, chocolate, peppermint, nutmeg and cinnamon. This variety (above) has lime-scented leaves and is sold as lime pink champagne. You can use scented geranium leaves to flavor baked goods or create scented potpourri, sugar or oil infusions. The essential oil extracted from a rose scented geranium known as Attar of Roses (Pelargonium capitatum) was popular at one point to replace expensive rose attar in perfume.
This group of geraniums also has the botanic name Pelargonium. The plants grow to different sizes, from 6 to 36 inches tall. Scented geraniums with smaller leaves tend to be smaller plants, while ones with larger leaves grow taller. Older leaves have stronger fragrance than younger ones. Popular varieties include sweet rose scented geranium (Pelargonium graveolens) and citronella scented geranium, which is said to repel mosquitoes (research says it doesn't really).
Scented geraniums are native to South Africa, which means that except for in the warmest zones, you need to shift these fragrant geraniums indoors for winter. Happily, these gems thrive in containers, which makes overwintering geraniums indoors easy.
Fancy leaf geraniums
As their name suggests, fancy leaf pelargoniums have variegated or coloured leaves in shades ranging from yellow, gold and dark green. They include 'Frank Headley', which has salmon pink/red flowers and green and white variegated leaves.
Princess Alexandra Geranium
The round foliage with white serrated edges and green center has upward-facing margins in a cup-form.
This compact variety offers golden-green serrated leaves with a purple-maroon center. It looks lovely with red-pink flowers.
Occold Shield Geranium
‘Occold Shield’ features heart-shaped leaves with wide green margins and a burgundy-red center. It stays compact and can also be an excellent tabletop plant.
Mrs. J.C. Mappin Geranium
The heart-shaped scalloped foliage has white edges and a green center. Flowers in matt white color add more beauty to its appearance.
A lot of decorative varieties date back to Victorian times but modern varieties are available, too. It's a very varied group – the flowers come in a range of forms and colours. They are particularly good for conservatories or as single specimen plants on the patio. Pelargonium 'Ashby', pictured, has dark pink blooms with a crimson centre.
Stellar pelargoniums were first bred in the 1970s in Australia and have been improved ever since. The starry flowers look delicate but they're actually pretty tough and long lasting, able to cope with scorching sun. Look out for the 'Fireworks' or 'Quantum' series.
Unique pelargoniums, such as 'Voodoo', pictured, are similar to the scented-leaved pelargoniums but have more showy flowers. Many have been around since the beginning of the 19th century. To keep the plant bushy, prune back by half in spring.
Geraniums may be grown as houseplants or as annual flowers. During the warmer months of the year (between your local frost dates), they can be kept outdoors in a sunny location.
If keeping geraniums as houseplants, be sure to bring them indoors in late summer or early fall, when nighttime temperatures start to regularly dip below 55°F (13°C).
When buying geraniums, pay close attention to color and size. Healthy leaves will have no discoloration on or below them and stems will be sturdy, not straggly. Be sure to avoid any plants with obvious signs of pests as well. Common houseplant pests include mealybugs, whiteflies, and spider mites.
Place plants in pots with drainage holes to avoid root rot.
Use a well-draining potting mixture (not heavy, clayey soil) when planting in containers. Geraniums do not like to sit in soggy, compacted soil.
For maximum bloom, place the plants in an area where they will get 4-6 hours of sunlight.
Allow soil to dry to some extent between waterings, then water thoroughly.
During the winter, water much less, but do not let the roots dry out entirely. Geraniums do best when given a period of dormancy through the winter months, during which they use less water and do not grow much. See below for more overwintering instructions.
To encourage blooming, deadhead spent flowers regularly.
To promote bushiness and curtail legginess, pinch back the stems.
During active growing months, fertilize every 2 weeks or so. Use a water-soluble fertilizer at half strength. Don’t fertilize in winter, when the plant should be dormant.
Geraniums can be re-potted in spring to encourage new growth—or if they look like they need to be refreshed.
How to Root Stem Cuttings
Most geraniums root easily from stem cuttings in soil, coarse sand, water, perlite, or other rooting material.
Using a sharp, clean knife, make a slanted cut 4 inches below a stem tip, above a node where leaves emerge. Trim cutting to just below a node. Remove any buds, all but two or three leaves, and the leaflike stipules at the base of leaf stalks.
Roll the stem cutting in newspaper or put it in the shade for 24 hours, so that the cut end will seal and not rot.
Push the stem into a pot of moistened rooting medium and store it in a warm, shady place for 2 days. After that, give the cutting indirect sun. Moisten the medium only as needed.
Pruning and Propagation
Regular pruning can help keep your plant in shape. Pinch back new growth several times in late spring to early summer to encourage branching. Faded flowers should be deadheaded regularly to boost blooming and extend the flowering season.
Geraniums are easily propagated from stem cuttings taken in spring, late summer, or early autumn; best when there is a lull in blooming. Cut just above a stem node; this will encourage re-growth on the existing plant. Cut the new cutting again just below a node about 4 to 6 inches below the leafy end of the stem. Strip all but the top leaves and place in warm, damp potting soil. Water thoroughly and place in a bright location but out of direct sunlight. Seeds can be sown indoors 10 weeks before last frost. Water lightly until seedlings appear and keep them in a warm location. Seedlings can be placed outside after all threat of frost has passed.
Geraniums that have spent the summer outdoors can be kept as houseplants, provided they get lots of sun. In northern climes, the sun may not be strong enough in late winter to stimulate buds on some varieties.
Before the first fall frost, lift the plants and, using a sharp, clean knife, cut the stems back in a shapely fashion to about 6 to 8 inches. They should not have to support great masses of leaves in the low-sunlight environment they are about to enter. Save a few stems as cuttings to root—an easy way to multiply your plants.
Transplant the “mother plant” to the smallest pot possible—enough to just fit the roots—using regular potting soil to fill.
Keep the plants in shade for a week, then place them in a sunny spot (they need all the sun they can get) and keep them cool.
During winter, geraniums grow best with night temperatures of 50° to 60°F (10° to 16°C) but will survive if they drop to 32°F (0°C) and/or rise above 80°F (27°C), as long as they are kept relatively dry.
When new growth appears in the spring, cut off all the old leaves.
The only thing more difficult than getting the new growth to appear is keeping it. And here’s some help with that:
Water only when the leaves show signs of drooping and provide only small amounts. Do not fertilize or feed the plants. It is critical that these plants get rest.
If you want your overwintered geraniums to bloom for Memorial Day, pinch them back in February. Once warm weather returns and all danger of frost has passed, take the plants outdoors and transplant them to beds or pots, as you wish.
Pests and Plant Diseases
Pests: Aphids, slugs and caterpillars can attack geranium leaves and flowers, but damage is usually minor. These pests are easily controlled by handpicking or spraying insecticidal soap or Bacillus thuringiensis kurstaki, a natural caterpillar control. Whiteflies may attack leaves in late summer. If present, you'll find them on leaf undersides. There's no need to treat whiteflies unless you plan to overwinter geraniums. Do not take a whitefly-infested geranium indoors, or you risk infesting all of your plants. The worst geranium pest is budworm, a moth larva (caterpillar) that burrows into flower buds, munching petals. When blooms open, petals have holes or are shredded. Often flowers rot before unfurling. Budworms are tough to control because sprays don't penetrate flower buds. Avoid overwintering potted geraniums that had budworms. If you must save them, get rid of the soil (that's where budworms overwinter).
Disease Problems: Geraniums are prone to fungal diseases, which readily start on spent blooms. Remove dead flowers regularly, snapping stems off at the base. Do not toss them onto the ground beneath the plants; instead bury them in the compost pile. If rainy weather soaks flowers and you notice fuzzy fungus starting to grow on petals, remove any flowers that show mold, whether or not they're fully open. This keeps fungus from overrunning the plant. Help prevent disease outbreaks by giving geraniums ample air circulation. Don't crowd plants in beds, and keep pots in areas where there's good air movement.
Benefits of Geranium
Blood clot activator
Geranium oil helps to stop blood flow through wounds as it causes the blood vessels to contract as well as it quickens the formation of blood clots which helps the wound healing faster. Geranium oil also restrains toxins from entering the body. Its styptic andhemostatic properties also help to prevent hemorrhoids.
Studies have proved that one of the beneficial properties of geranium is that it is cytophylactic. It can proficiently boost metabolism which is vital for upholding the health and the growth of a body and reproductive cells. It also helps in recycling of dead cells present in the body.
Relieves stress and fatigue
Inhaling the aroma of geranium oil can act as a pick-me-up for one’s soul and reduce fatigue. It also has a positive impact on the mind and body. The effect of geranium on the nervous system is remarkable and it’s been used in this way since the days of yore. The leaves of the plant can be brewed to make tea which has soothing properties and helps to calm nerves down. Geranium oil has several organic compounds that keeps endocrine system healthy and balances hormone that causes stress.
Geranium oil has diuretic property which is extremely helpful when it comes to detoxifying body as it is a strong antioxidant. Sometimes toxins are produced within the body during metabolic processes out of which some are eliminated by means of the digestive tract, and perspiration. It eradicates the noxious free radicals that lurk along with vital nutrients from the body. It also helps in detoxification by levelling the rate of urination. This process of elimination does not only flush out toxins but also helps the digestive function.
Geranium oil is astringent in nature; it generates contractions in many parts of the body and helps to fight with wrinkles by clenching facial skin and curbing the effects of aging. This aromatic oil is a natural cleanser thus it radiates skin. Furthermore it is a cicatrisant that removes acne and scars.
Cures Athlete’s Foot
Geranium oil is well known for being one of the most widely studied oils in the market. It is amongst the best natural alternatives versus the creams and lotions that doctors recommend to combat fungal infections like athlete’s foot.
Cures respiratory problems
Geranium isn’t known as a health booster in general for a reason. It is useful and cures ailments for several organ systems. It is very helpful to the respiratory system which is prone to weather changes. Several such ailments can be treated with the help of geranium.
Anti inflammatory property
Research shows, inflammation is correlated with every third health condition. Thus, researchers are investigating persistent inflammation’s effects on body and preventive measures for it. It is scientifically approved that geranium oil has the capability to enhance the effect of anti-inflammatory drugs. Geranium oil obstructs the inflammatory responses in the skin which aids the body to fight health issues.
Geranium oil generates microglial cells that discharge pro-inflammatory agent that enables inflammation in sensory paths, preventing the development of neuro-degenerative ailments. Geranium oil performs reactions with the chemistry of the brain that helps to prevent alarming conditions like dementia, amnesia, Alzheimer’s, etc. that lead to memory loss.
Geranium oil is very efficient in alleviating pain caused due to nerve disturbance arising through diabetes or several other ailments as in sclerosis and lupus. Compressed nerves cause unbearable pain which can be lessened by applying geranium oil on the skin and also the shingles caused due to herpes virus.
Geranium oil provides comprehensive physical and emotional health benefits due its astringent, hemostatic, cicatrisant and diuretic properties. Though essential oils have been used since generations they are not regulated by the food and drug department. Geranium oil can be used to relieve stress, alleviate pain due to wounds and is also used for premenstrual problems, nausea, diarrhea, gall stones, etc.
Several African Pelargonium species are commercially important for geranium oil, an essential oil used in perfumery. Geranium oil, which is also called pelargonium oil, or rose-geranium oil, is colourless to pale yellow-brown or greenish and has an odour like that of roses. It is used chiefly in perfumes, soaps, ointments, and tooth and dusting powders. The edible leaves and flowers are also used as a flavouring in desserts, cakes, jellies and teas.
Scented leaf pelargoniums have also been historically used as toilet paper by fishermen in remote places, such as the Minquiers. Scented-leafed pelargoniums can be used to flavor jellies, cakes, butters, ice cream, iced tea and other dishes, The rose-, lemon- and peppermint-scents are most commonly used. Also used are those with hints of peach, cinnamon and orange.