Everything You Need to Know About Growing Hardy Geraniums

Written by Hannah Miller. Fact checked by Daniel Woodley. Published to Summer Flowering Plants on the 6th of September 2022.

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Hardy geraniums are one of the most popular plants in the UK, and for good reason:

  • Tough and resilient to pests
  • Easy to grow
  • Compatible with many other plants
  • Good foliage cover
  • Great for pollinators
  • They flower for months
  • They come back reliably each year

Let us show you how to grow and get the most from hardy geraniums.

But first…

What’s The Difference Between Hardy Geraniums and Bedding Geraniums?

Hardy geraniums (aka cranesbills) are herbaceous perennials that die back to ground level for the winter and reappear the following spring.

“Bedding Geranium” is a common name for pelargoniums – an entirely different species of plant that is an annual in the UK. Pelargoniums are often used as bedding in borders, troughs and hanging baskets.

In short, they are different species, and hardy geraniums come back year after year, while bedding geraniums usually die off as winter approaches.

Difference between hardy geraniums and bedding geraniums

Hardy Geranium Fact Sheet

Size

Variable 

Height: Usually 40cm (16″) to 100cm (40″)

Spread: Usually 50cm (20″) to 150cm (60″)

Type

Type

Hardy herbaceous perennials – they die down as winter approaches and come back in the spring

Growth icon

Growth

Moderate growth rate, hardy geraniums usually reach their full size by year 3

Difficulty

Very easy to grow and forgiving

Native

Europe, Asia, Americas

Location

Exposed or sheltered in pots, borders, edging and underplanting

Sunlight

Most prefer full sun to light shade while some prefer more shade

Hardiness

Hardy in all parts of the UK

Water & Feed

Hardy geraniums prefer moist but well-drained soil

Companions

Hardy geraniums are often planted under tall-stemmed plants such as coneflowers or alliums but can be placed next to many other plants inc shrubs

Planting

Bare roots can be planted at any time provided the ground isn’t frozen. Potted plants can also be planted out at any time except frost. Dig in fresh compost and the hardy geraniums should take off with little fuss

Flowering

The flowering season varies but is usually from late spring and early summer with some holding onto their blooms into the autumn

Purple hardy geranium flowers

Get The Most From Hardy Geraniums: 12 Questions Expertly Answered

How and When are Hardy Geranium Plants Sold?

Rudbeckias are sold as:

Seeds: rarely as they are difficult to get going.

Potted Plants: Best planted in the spring but can be put down anytime except frost.

Bare Roots: Usually available to pre-order from December with delivery at the end of winter or the start of spring.

What's Great About Hardy Geraniums?

Hardy geraniums are usually grown for these reasons:

  • They make for perfect underplanting where their foliage hides the stems (such as roses) or the ugly foliage (i.e. alliums) of many plants.
  • They are carefree and once settled, require little care and attention.
  • The dainty blooms come in bright colours.

Where Should Hardy Geraniums be Planted?

Most hardy geraniums will thrive in full sun or light shade provided the soil is kept slightly moist and free draining.

Some will tolerate more shade.

How Should They be Planted?

Bare root plants should be dug into a hole so the top of the plants is at ground level.

Potted plants can be transferred to the garden in the normal manner.

A good dose of fresh compost will help them on their way.

Do Hardy Geraniums Need Watering and Fertiliser?

Hardy geraniums prefer moist but free draining soil so should be watered accordingly.

Potted geraniums will require more water, especially if the pot is on a hot patio or on full sun.

A twice-yearly dose of fertiliser and a twice-yearly mulch with fresh compost or other organic matter is usually enough for most hardy geraniums.

Do Hardy Geraniums Set Seed? Are They Invasive?

Many hardy geraniums are non-native but they aren’t particularly invasive and are easy to control.

Non-sterile geraniums will set seed and offspring can often be found in the vicinity of the original plant.

Growing from seed can be hit and miss and it’s usually easier to dig up seedlings that have germinated naturally.

What Pests and Diseases Affect Hardy Geraniums?

Hardy geraniums are tough plants that hold up well against diseases and most pests.

Slugs and snails leave them alone but sawflies can devour much of the foliage, leaving behind holes.

The best treatment for sawflies is a contact bug pesticide such as Provanto Bug Spray.

Powdery mildew can of concern but can be contained with readily-avoidable sprays and by watering from the side rather than overhead which causes splashes.

How Long Do Hardy Geraniums Flower For?

Most should flower from late spring to late summer but if given the Chelsea Chop, they last even longer.

Can I Grow Hardy Geraniums in Containers?

Yes, but they may struggle in overly dry soil and heatwaves, so water more frequently and top up with compost throughout the growing season.

Are Hardy Geraniums Poisonous to Humans or Pets?

No reports of toxicity in humans or pets could be found when we searched online in 2022.

Are Hardy Geraniums Beneficial to Wildlife?

Yes.

Bees, butterflies and other pollinators love hardy geraniums and birds will eat the seeds too.

How Difficult are They to Grow?

Easy – hardy geraniums often make it onto “best plant” lists as they are so versatile, tough and easy to grow.

How to Care for Hardy Geraniums After Flowering

Hardy geraniums don’t require any special care after they’ve finished flowering and will normally die back to ground level after the first frosts.

You can leave the dead foliage in place or cut it off an inch above the ground at any time.

If your hardy geranium has put on an early show, you can give it the Chelsea Chop – a term that means cutting back the foliage in early to Mid June. Most (but not all) hardy geraniums will reward you with a second flush of blooms, often well into late summer.

Cut the foliage back to a couple of inches above the ground for best results. Even if the hardy geranium doesn’t produce any fresh blooms, it will still put out fresh foliage.

Dense colonies of hardy geraniums can be lifted and divided in the spring.

Companion Plants

Hardy geraniums are one of the most versatile plants you can grow and gardeners successfully grow them with hundreds of other species.

As these geraniums put on a lot of dense foliage, they make excellant groundcover plants and are perfect for hiding the wilting foliage on alliums and tulips.

Gardeners often grow them under roses, coneflowers and other tall plants to hide the stems.

You can try growing these geraniums next to almost any plant, they are generally very tolerant and will thrive in full sun, light to moderate shade and in shelter or open areas.

If you’ve never grown a hardy geranium before, start with Geranium “Rozanne” which won the prestigious “plant of the centenary” at the Royal Horticultural Society in 2013:

  • Deep violet-blue-purple flowers to 5cm wide
  • Purple veins
  • White centres
  • Height: 90cm. Spread: 90cm
  • Flowers from June to September
  • Produces a mound of deep green foliage
  • Perfect for under roses or filling gaps in borders

Buy Geranium “Rozanne” here

Geranium Rozanne flower

Our Experience With Hardy Geraniums

Here is a quote from Daniel, our co-founder:

I currently have several hardy geraniums in my border, they hide the yellowing foliage of the alliums and also sit delightfully next to my coneflowers.

I’ve also split them several times over the years and used them to fill gaps between plants as they’re so versatile.

Hardy geraniums have made it onto several of our “best of” plant lists here at DIY Gardening:

More From Hannah Miller:

Hannah Miller wrote this guide to growing hardy geraniums which forms part of her Summer Flowering Plants Collection.

Hannah is a keen gardener who is trying to reduce her use of pesticides and move to organic gardening.

She’s also a mother and former NHS administrator with 12 years of experience. She also speaks English, Russian and Ukrainian fluently and enjoys travelling around Europe.

More About Hannah Miller.

Hannah Miller

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This growing guide was published by DIY Gardening

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Hannah Miller
Danny Woodley