Like anything, geranium care is easy – when you know how. But if you don’t know how to care for geraniums properly, you can run into plenty of mysterious problems.
If that’s the case for you, get ready to fix that because everything you need to know about planting, feeding, pruning and overwintering geraniums is covered in this guide to geranium care.
This also covers prepping ground soil because if that’s not done right, roots suffer and that leads to problem plants.
What are Geraniums Exactly?
Not all geraniums are in fact geraniums thanks to Europeans. Some are pelargoniums.
Geraniums are native mostly to South Africa where hundreds of species grow, however they’re also a popular plant species throughout the US, EU, UK, and Australia. Some confusion arises between the two because of the really close likeliness.
A pelargonium is a hybrid species of the geranium plant. The difference between a geranium and a pelargonium is in how they flower and that hardy geraniums are frost tolerant while pelargoniums aren’t.
The noticeable differences are that a geranium has a flat-like saucer shape while a pelargonium has a trumpet-like shape of flower that faces upward from the stem, rather than a flat five-petal flowerhead.
When buying geraniums, if it’s labeled as hardy, those are usually geraniums, not pelargoniums. The name botanists use for true geranium species is cranesbills.
Some types of hardy geraniums can withstand frosty conditions. Every type of pelargonium will need brought indoors for over-wintering. If you want to grow geraniums outdoors only, be sure to get hardy geraniums.
If you don’t mind (or want) to overwinter your plants, a pelargonium will give you the same types of flowers, just with a little more height to the flowers as the petals usually have two sitting just below a lower level of three petals, rather than the flat flowerhead you’ll see with cranesbills.
There is a slight symmetrical difference between pelargoniums and geraniums too, but caring for either type of plant is the same (except for the frost-tolerance part).
Both types can be overwintered indoors so if you aren’t sure what type you have, overwinter it as a precaution.
There are hundreds of species of geranium because hybrid species are accepted by the general term of geraniums in most nurseries and garden centers.
However, of the possible thousands of species, each can be narrowed into just five distinct groups.
Zonal geraniums get their name from the different bands of color that appears on each flower. On other types of geraniums, the colors are usually solid with varying shades such as light pink to deep red.
With zonal geraniums, each flower can have alternating colors on the flowers such as green, white, yellow, orange and red.
It’s the wider variety of colors on the flowers that make these popular as border plants and also why these are mostly referred to as the garden geranium.
Due to the popularity of these, you’ll see Zonals on display in garden centers, despite them being pelargoniums.
The regal geranium is also known as a King Pelargonium, Pelargonium Grandiflorum, and the English Pelargonium. It produces vibrant flowers every year, provided it is overwintered indoors with temperatures above 550F.
These bloom throughout the summer lasting to early fall producing large trumpet shaped leaves with six petals surrounded by lush green serrated edge foliage.
They are ideal for indoors and for planting outdoors in Spring and Summer as border plants, for using as a potted plant on your patio or in raised flower beds.
Some regal specimens are scented making them great for brightening up gardens and homes while also scenting the air.
Ivy geraniums are your go-to spreading flower that are absolute perfection for hanging baskets. These grow fast and are extremely easy to propagate.
Blooming throughout the summer, it’s possible for these to cascade up to 6 feet making them ideal to use in hanging baskets or as a spreading flower to fill up garden space with a range of bright colors.
Scented Geraniums have some surprising uses because they’re also herbs. Being edible, they can be added into recipes and drinks. Some of the most used in recipes are citrus, fruit, rose, spiced and nut varieties of scented geranium plants.
An additional perk with the citrus variety is that you can use them as a mosquito repellent (see some of my other options).
However, if that’s your reason for growing them, you need to know how to use the plants for that purpose because there’s no plant you can put in your garden that’ll completely keep insects away.
About the Mosquito Plant
Despite garden centers and nurseries selling lemon scented plants described as either a mosquito plant, mosquito-repelling plant, or just by the general term ‘Citrosa,’ they are only effective when the leaves are disturbed as that’s where the oils are that repel the insects.
To use the oils from a lemon geranium as an insect repellent, the leaves can be rubbed on your skin directly (provided you aren’t allergic) or boiled in a pan to release the aroma or burned.
It’s the oils from these citrus plants that are used to make citronella candles you can buy in jars to burn outdoors. You can put them in a bamboo torch near where you’re sitting outdoors to enjoy the space free from flying pests.
Scented geraniums aren’t as widely available in garden centers as other varieties because nurseries tend to grow for commercial purposes, selling wholesale to aromatic oil manufacturers who extract the oils then sell those bottles to candle makers, scented soap companies and perfume manufacturers.
Additionally, some varieties of scented geraniums such as the rose geranium have high anti-inflammatory properties making them a big deal in the pharmaceutical industry.
Hardy geraniums are the common name for a Cranesbill Geranium, which are the real deal. These are surprisingly easy to grow and can give a vast amount of ground coverage as they can spread to around 4 feet in width.
Heights can be as high as 8-feet if they aren’t cut back making them useful as a second-tier plant in a flower bed or border plant arrangements supporting any other variety of pelargoniums that have shorter stems.
How to Grow Geraniums from Seed
To start growing geraniums from seed, you’ll need either a flat tray (preferably with a lid) or a seed starter kit. Both do the same thing but if you’re only using a flat tray with soil, there’s more transplanting involved.
Ideally, use a seed starting kit with a lid.
If you’re unfamiliar with starting plants from seed, use a pre-prepared potting mix for starting seeds. They contain three things: peat moss, perlite and vermiculite.
The peat moss is the main growing medium. Perlite and vermiculite are added to increase aeration.
Depending on the brand of seed starting mix you use, there may or not be fertilizer already added. If not, it won’t stop you starting to grow geraniums.
Once the seeds are germinated, you can then add a water-soluble balanced fertilizer to help spur healthier growth after a couple of leaves have grown, usually after one week provided there’s sufficient lighting.
Fill each cell of your starting tray with the starter mix then pat it down gently so that it’s settled in the containers but not so much that it becomes compact, which then reduces air circulation.
Add one or two of your geranium seeds to each cell. If you’re using a flat tray, leave at least 6” of space between each seed, then add a sprinkle more soil over the seed and water in gently.
This is easier done with smaller watering can rather than the larger cans you’d use in the garden.
Once watered, you can either place the tray on your windowsill or under grow lights (see my guide to using grow lights for more info).
If you are using grow lights, the seeds will need between 12 and 16 hours of light per day. If your tray has a lid, remove it as soon as the first leaves form to increase air circulation.
Grow lights should be around 6” to 8” above the plant with a consistent temperature between 70oF to 75oF.
While it is possible to place your tray on a windowsill to let your plants grow with sunlight, it takes longer because temperatures drop in the evening and there’s not as many hours of sunlight to promote healthy growth.
Also, as the light isn’t directly above the plant, like all plants, they grow towards light, which can result in spindly, leggy growth. Grow lights prevent this.
If the conditions are right, your geranium seeds will germinate within a week.
After a couple of leaves have grown, add in some balanced fertilizer and keep all other growing conditions the same. You can continue to keep growing in the tray by cutting the geraniums back until you’re ready to use them in your garden, in a hanging basket or plant them up in a container.
Once you’re ready, transplant them in small 4” plant pots ready to plant in the garden or in decorative plant containers for indoors.
When transplanting geraniums that have just started, the stems are delicate. Handle them by lifting gently by the leaves instead of the stem. The plant can repair damaged leaves faster than the stems.
Hardening Off Geraniums Before Planting in the Garden
When geraniums are grown from seed under artificial conditions, they’ll need acclimatized to outdoor conditions. For that reason, it’s best to transplant into pots first before you put them in the ground, or you can just keep them in the pots so you can move them around the garden.
Start by placing your potted geranium outside in a partially shaded area, then over a week to ten days, gradually move it to brighter, sunnier locations until it’s in the part of your garden you want to keep it permanently.
Geraniums are sun-loving plants favoring six to seven hours of full sun daily once they start growing.
How to Root Geranium Cuttings
Growing geraniums from cuttings is the most common way for them to be grown and it’s super easy to do. The best time to take a cutting is around autumn before the temperatures drop.
Take a cutting of about 4″ in height from a new shoot that hasn’t flowered. Cut just below a leaf joint at a 45-degree angle and then trim off all the lower leaves.
Where you’ve removed the leaves, you’ll notice small stipules on the stem. Remove those too by pinching them back.
If they’re left on the cutting, they can cause botrytis disease, which is a soft rot plant disease that causes gray mold to attack the plant and it will prevent it from rooting.
Here’s how to take cuttings from geraniums that will root in one week in the fall:
Once you have a healthy cutting, place that in a small container pot with drainage holes and use a seed starting kit the same as you’d use with geranium seeds – peat moss, perlite and vermiculite.
Depending on the size of container you’re using for rooting your cuttings, you should be able to root up to a half dozen cuttings in the one container.
The only thing not to do is cover the pot as you’d do with seeds in the beginning. Allow for good airflow.
Geraniums root easily so you won’t need to apply a rooting hormone powder, however, you may want to try using Vitamin C instead as geraniums seem to love their vitamins.
Just take a vitamin C tablet, dissolve it in water, dip the cutting into the water then put it in the container to root.
Better yet is to use honey as a rooting hormone as it has anti-fungal properties that help to protect the plant from fungal infections while promoting strong and healthy root growth.
You don’t need either Vitamin C or honey as geraniums are easy to root with nothing added. However, adding something natural to strengthen the root system will make caring for geraniums easier once they’ve grown into healthy plants with plenty of foliage and vibrant flowers.
If you aren’t using the standard seed starting mix to grow from cuttings, the alternative is to use any well-draining potting soil, such as compost with sand or grit added to improve drainage.
How to Plant Geraniums
Geraniums are sun-loving plants requiring between six and seven full sun daily through the growing season. The best time to plant geraniums in the ground outdoors is early spring right after the last hard frost.
You can either plant these directly in the ground as border plants, in flower beds, or grow them in containers or a hanging basket.
If you’re planting directly into your garden soil, make sure it’s well tilled first.
Preparing Garden Soil for Geraniums
A good soil base is essential for any plant to thrive. For best results, don’t just pick a spot in your garden, drop your geranium in and expect it to produce colorful flowers abound.
Prepare your soil to give it the best start by tilling your ground soil first.
Tilling soil is easier on your back and better for the soil when you work it when it’s damp because if it’s too dry, it’s hard on you to turn it over and it’s rough on the soil. Too wet and it’ll clump together.
Lightly water the soil first, then dig to a depth of 6” to 8” using either a shovel or garden fork to turn the soil over. When you turn it over it should fall apart, look moist and not be dripping wet.
If you have the elbow-grease to manage to turn the soil at a depth of 12”, even better and if you don’t mind some hard labor, double digging to a depth of 18” lays the best foundations for root plantation.
Weed Control when Prepping Ground Soil
The deeper you dig to till your soil, the more likely it is you’ll find weed seeds that haven’t germinated because of a lack of light. These will need to be controlled to prevent weed germinating seeds from battling for nutrients with your geraniums.
Once your soil is turned and ready to plant your geraniums, treat it for weeds first.
Using pre-emergent weed control will prevent weed seeds from germinating, but it’ll also do the same for anything you plant in the soil after application. If you’re treating your ground soil with a pre-emergent, you won’t be able to use that area for plants for 12-weeks.
If you don’t want to wait 12-weeks, the faster approach is to use mulch, either organic or a non-organic landscaping fabric. Organic mulch is the better option as it’s disadvantageous to weeds yet beneficial for geraniums.
Pine leaves, cedar, bark and leaves make for good mulching options. Apply a layer of mulch that’s 2” to 3” thick then work that into the soil by turning it over, keeping the majority of it near the top.
Something to remember when you’re adding mulch is it will make the soil retain water. Geraniums prefer well-draining soil so be careful you don’t add too much. Perlite can be added to improve soil drainage.
Spacing Requirements for Geraniums
Geraniums, like all plants, grow better when they have sufficient air circulation so they can’t be overcrowded. Different species have different spacing requirements.
If you’ve bought your plant ready to put into your container or hanging basket, follow the directions that came with it.
For those who are growing from seed or cuttings, the distance to leave between each plant differs by the type you have. It’ll be easier to gauge the distance you need by the width of the plant you took the cutting from.
Some guidelines for spacing are listed below:
- Cranesbills – Space 18” to 30” apart. The wider apart these are planted the better as these are spreading flowers that can spread to a width of around 3-feet.
- Ivy-Geraniums – Two plants per 8-inch container/hanging basket. If you’re using these as ground cover, you’ll need to leave about 36” between plants because they are spreaders. In hanging baskets and containers, they can be closer because the branches fall over the edge trailing down, rather than spreading across the ground.
- Zonal Geraniums – between 12” and 24” apart, depending on the species.
- Regal Geraniums – Plant these 12” apart.
- Scented Geraniums –12” apart as well.
Geranium Care: Pinching, Pruning and Deadheading
Getting geraniums to germinate is the first part of growing, but getting them to flower is something entirely different that requires pinching.
When and how you do this depends on the time of year and whether your geraniums have been grown from cuttings or just been overwintered indoors.
Important note: When you pinch geraniums, you’re cutting back active growing stems and that will delay flowering. But, the point of pinching is to double the flowers produced.
So, while it will delay flowering, you’ll get far bushier plants and double the amount of flowers the plant produces making it well worth the effort.
The Difference Between Pinching and Pruning
Pinching and pruning are terms that are often used interchangeably but there is a difference.
Pinching is the least aggressive approach to controlling the direction of your plant’s growth as you only need to use your thumb and forefinger to gently pull part of the plants stem off.
Pruning on the other hand uses sharp pruning shears to cut the stem.
Pinching is done on new growth and pruning is used on older growth to encourage new growth.
Pinching Geraniums in the Spring
Spring is the best time to pinch back geraniums just as new growth begins. This is best done once around 2-inches of stem.
When your plants stem reaches 2”, pinch about a ½ inch off it. What happens is that where you pinched the stem, it’ll be replaced by two new stems, each producing flower heads later in the season.
For geraniums grown from cuttings over the winter or overwintered indoors, you’ll need to do this twice to get good results. Once in January when new tips start to develop and again in early Spring.
Pruning Geraniums in the Fall
Pruning is a more aggressive approach because it means removing branches from your plant that cuts it back to between a third of its size or by half. It’s needed though.
The reason being, older stalk won’t produce as vibrant of flowers and the ones that do flower, if not properly pruned won’t look their best when they do come through.
They can wind up straggly and leggy with brown leaves soaking up nutrients that should be going to healthier parts of the plants.
For pruning, you’ll need a pair of sharp pruning scissors so you can cut the stems at a 45-degree angle. Sterilize them first before using.
You can cut these back to just 6” above the soil without worrying about the height it’ll grow back to because they will grow fast.
The parts of the plant you’re looking to remove are any that look old. That might be as few as just four to six stems left and that’s fine as those will produce more, so don’t worry about being too aggressive when cutting it back at the end of the year.
By pruning in the fall, you’re getting the geranium ready for overwintering so you only need a few good healthy stems that can get the most nutrition after it’s been dormant over winter.
During bloom, geraniums and pelargoniums need deadheading frequently for the same reason as pinching and pruning is done. To direct the plants energy into producing more flowers with more color. Whenever you see flowerheads looking dull, pinch them off. Hold the stalk in one hand and pull the flower downwards to remove it.
There are a couple of ways to overwinter geraniums:
- Bring them in and use them as houseplants
- Let them go dormant over winter
An alternative is to grow new geraniums from cuttings, as described above.
Using geraniums as houseplants in the winter
The easiest, if you have the space on a windowsill, is to use them as houseplants over the winter, requiring water just once a week. They tend to be drought tolerant so it’s to let the soil dry out between watering them.
If you are going to bring these in from outdoors to grow inside over the winter, cut them back to around a third of their size and pot them up in a container with potting soil.
They’ll still need a good amount of sunlight so a south-facing window is best. However, as the conditions are different from outdoors, not all types of geraniums will grow well when brought inside.
If you find the blooms the plant’s producing are less colorful, or it isn’t looking its healthiest, it’s probably better just to give it a rest by letting it go into dormancy until the spring.
Overwintering Geraniums in Dormant Storage
Another option with geraniums is to dig them out of your garden, pot them in containers and store them in a dark room such as a basement or garage and let them hibernate over the winter.
It’s the rest they need to come back into full bloom next season.
The only thing you need to take care of is the stems because it won’t be producing anything over the winter. To maintain the health of stems on geraniums, soak them in lukewarm water for one to two hours every six weeks or so during the winter.
During dormancy, temperatures should be maintained between 45oF and 50oF (between 8oC and 10oC). Leaves will fall off and the ones that don’t should be cut off.
By early Spring, you’ll be able to bring them out of storage and place them by a sunny window and start to see new foliage shoot from healthy stems.
Then it’s as simple as pinching the new stems back by a half inch when they reach a couple inches in height, and getting them ready to replant outside.