how to plant, grow & care for geraniums
complete growing guide
Geraniums are the relatives of our native wildflower, the Cranesbill. They are totally hardy, unlike their frequent namesake the Pelargonium. They work as brilliant ground cover under shrubs and trees, there are smaller varieties suitable for rock gardens, but many varieties warrant a place to themselves with their striking colours and markings on the flowers and foliage. We have a range of traditional and new cultivars to suit all situations, browse our range of geranium plants to find the right one for your garden.
details
- Common name: Cranesbill
- Latin name: Geranium
- Type: Hardy Perennial
- Height: 15cm (6in) to 90cm (3ft), depending on variety
- TLC rating: Easy
- Aspect: Full Sun or Part Shade
- Planting position: Front of border, ground cover under shrubs and trees
- Suitable for pots: Yes
- Good for pollinators: Yes
- Good for cut flowers: Yes, for small vases
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how to grow geraniums
where to grow geraniums
Soil type: Geraniums are not too fussy about soil types, like most things they prefer it moist and well drained, but once established they can survive in the rain shadow of walls, shrubs or trees.
Aspect & position: Geraniums are happy in either full sun or partial shade.
when to plant geraniums
Geraniums can be planted in the spring, from March to May, so that they can get established before the hot weather and give you flowers all summer long. You can also plant in the autumn from September-October while the soil is still warm, then they will get a really good root system established and start flowering for you in the spring.
how to plant geraniums
planting geraniums
When your plant arrives give it a good drink by standing the pot in a bucket of water for about 20 minutes. Meanwhile dig a hole a little bigger than the pot and mix in a little garden compost at the bottom of the hole. Mycorrhizal fungi (Rootgrow) sprinkled onto the rootball will also help. Fill the hole with water and let it drain away. Turn the plant out of the pot, tease out the roots if they seem congested and put it in the hole, firming the soil around it. One more drink of water to settle it in, and water during dry periods if planted in spring.
growing geraniums in a pot
If you want to grow geraniums in a pot, ensure you use a soil-based compost, enriched with a bit of garden compost if you have it. Your geraniums will need regular watering as they are naturally quite thirsty plants.
how to care for geraniums
watering
Geraniums really are so easy to look after. They do not require watering once they have settled in unless it is a particularly dry period. Geraniums grown in pots will need regular watering.
fertilising
On the feeding front, an autumn mulch after you have cut the leaves back will help improve the soil and boost flowering the following year.
staking
Staking geraniums is unnecessary, apart from the occasional hoop to stop them spreading over a path in their general exuberance and willingness to please.
cutting back geraniums
Geranium varieties that flower in late spring and early summer can be cut back which will give you a clump of fresh leaves for the rest of the season.
Other varieties will flower all season long but slow down on the flowering around mid-summer. This is where a general haircut pays dividends. Shear off all the leaves to ground level (or to where you can see some fresh new leaves have started to emerge). The plants will thank you for a water with seaweed fertilizer and a mulch of garden compost if you have some, and with luck you will have a fresh flush of flowers in a few weeks. I try to get this done just before I go on holiday so I don’t have to put up with the close-cropped look, and can come back to some lush new growth.
Another way to ensure a succession of flowering through the summer (if you are made of stern stuff) is to deploy the ‘Chelsea Chop’ in late May. Pick a few plants (perhaps those close to a path that are prone to flopping over) and just as they are about to flower you shear them back to half their height. This means that they will flower a few weeks after their neighbours, and will be stockier and stronger for it.
propagating & dividing
Geraniums are also very easy to propagate. You might find that after two or three years they are beginning to crowd out their neighbours. Spring is the time to take a fork to the outside and remove a few new clumps around the edge that are rooting out of bounds.
After five years or so you might notice the centre is looking a little woody and less floriferous. Time now to dig out the whole clump and divide it up using the back-to-back fork technique. Discard any old woody sections from the middle and replant the fresh new clumps for better flowering next year. You might even have some spare sections to hand on to friends.
taking geranium cuttings
Cuttings are easy to do and will reward you with better plants. Geraniums are one of the plants that actually have better growth and flower density from younger stock.
Take lots of cuttings from your geraniums in April and they'll be ready to be replanted in a month and be in full flower in three. This is the moment to multiply your geraniums so you have marvellous pots and fragrant leaves and velvety flowers for picking all through summer, autumn and into next winter.
Cut your geranium plant back by two-thirds, aiming to cut immediately above a lateral bud – or a node with a bud potential. These stem tips will form the basis of your cuttings.
If you want to keep the mother plant – and with geraniums I tend to keep the grandmothers and great-grandmothers – thin out all the spindly wimpy stems, leaving maybe seven or eight good ones to grow on. Then pot them on with a good surrounding of new, nutrient-rich multi-purpose potting compost.
Cut the best-looking geraniums cuttings into 4in sections, discarding any that don’t have plenty of shoots or nodes. With each section, strip almost all the leaves from the stem, leaving only the top pair. Also pinch out any tips that look like they might develop into flowering shoots.
Insert the geraniums cuttings to about a quarter their depth into a gritty mix of compost. I love using these square bulb trays for cuttings. They look good in them – as they sit and root – and you can fit lots in, spaced well and evenly apart. Put them on a heated base if you have one, or store them somewhere bright, but cool and keep their compost moist at all times.
Geranium cuttings should have rooted within a month and can then be potted on. If you want a great tumble of flowers and leaves, plant three to a large pot, they will quickly grow to appear as one bumper-sized plant, healthy, floriferous and handsome.
overwintering
Most geranium varieties will die right back in the winter, so if you are a tidy gardener you can shear the dead leaves off and add them to the compost heap. They are bone hardy so don’t need any winter protection.
seasonal checklist
spring
- Plant geraniums and water in well, use a little rootgrow when planting.
- Propagate by division and transplant new clumps elsewhere in the garden.
summer
- Late May: Cut back a few plants to half their height to delay flowering.
- July/August: Cut back spent flowers and leaves to ground level to encourage a second flowering.
autumn
- Cut back dead leaves and mulch around base of plant.
winter
- Decide which geraniums you want to plant in the spring.
pests, diseases & common issues
Given that the hardy geranium is very closely related to our native cranesbill it is very well adapted to the British climate. It does however have a couple of attendant pests and diseases that it seems to shake off pretty easily.
geranium sawfly
This looks like a small 12mm long greyish green caterpillar and will start to eat holes in the foliage in the late spring. If you spot round holes in the leaves look underneath and squash any culprits that you find. Given that we expect geraniums to withstand the ‘Chelsea Chop’, the occasional sawfly hole is not going to cause much upset!
geranium downy mildew
This begins as discoloration on the upper surface of the leaves, and if allowed to develop will turn into an off-white fuzzy growth on the underside, and the leaf will eventually shrivel up and die. It is caused by moist humid conditions and insufficient air circulation. A drastic hair cut might be just the solution, and this time make sure you pick up and dispose of (not compost) the affected leaves.
rabbits and deer
Rabbits and deer will occasionally browse on geranium foliage, but won’t do any permanent damage.
frequently asked questions
are geraniums perennial?
Yes, they certainly are, and even the tender pelargoniums that are frequently confused with hardy geraniums are also perennial – just as long as they have winter protection.
are geraniums poisonous to cats or dogs?
This is where knowing your geraniums from your pelargoniums could be crucial. Geraniums are not toxic to mammals (hence the rabbits and deer being partial to them), but some pelargoniums can be mildly poisonous to pets.
do bees like geraniums?
Bees adore geraniums. I have seen vibrant clumps of geranium psilostemon humming with bumble bees, honey bees and a wide range of other pollinators.
will geraniums survive winter?
The hardy geraniums will certainly survive a winter outside, tender pelargoniums, however, will not.
do geraniums spread?
Yes, some varieties will stay as neat clumps only gradually increasing. Others will spread very quickly so need to be kept in check.
can geraniums grow in shade?
Yes, they are quite happy in partial shade. though the smaller varieties prefer a spot in full sun.
can geraniums grow indoors?
No, a hardy geranium would find it too hot and dry indoors.
which geraniums are scented?
No hardy geranium flowers have any scent, apart from the foliage of Gernanium macrorrhizum which is strongly aromatic, and therefore less palatable to rabbits and deer.
what to grow with geraniums
As geraniums come into leaf relatively late in the spring, they combine well with early spring bulbs such as snowdrops, scillas or crocus. They can also help to conceal the scruffy leaves of alliums as they die down.
how to cut & arrange geraniums
Geranium flowers and leaves have beautiful intricate markings so they work well in a vase, or perhaps a series of vases arranged along a windowsill.
Get more inspiration for displaying your flowers with our flower arranging videos:
