How to Keep Geraniums Alive in Winter | Winter Gardening Tips UK

Introduction: Protecting Your Geraniums from UK Winter Frosts

Geraniums (also known as pelargoniums) are a firm favourite in UK gardens thanks to their vibrant flowers, long blooming season, and easy care. However, they’re not frost-hardy, meaning that if left unprotected, the cold UK winters can quickly kill them off.

If you’ve lovingly grown your geraniums all summer and don’t want to start again from scratch each year, you’ll need to take action before the first frost hits. In this winter gardening guide, we’ll walk you through how to overwinter geraniums in the UK, whether you grow them in pots, borders, or hanging baskets.

1. Why Geraniums Need Protection in UK Winters

Understanding Their Sensitivity to Frost

Geraniums are native to South Africa and struggle once temperatures drop below 5°C, especially if exposed to freezing rain, snow, or strong winds. Even a light frost can damage their fleshy stems and kill the roots.

Protecting them from the worst of winter ensures:

A healthier head start in spring.
Cost savings from not rebuying plants each year.
More mature, bushier plants over time.

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2. When to Bring Geraniums Indoors

Timing Is Everything

Start watching the weather forecast from late September to mid-October. As soon as consistent overnight temperatures drop to 8°C or lower, prepare to bring your geraniums indoors.

Don’t wait for a frost warning — by then it may be too late.

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3. Methods for Overwintering Geraniums in the UK

There are three main methods to overwinter your geraniums depending on space and plant type:

A. Keep Them Growing Indoors

Best for: Healthy potted geraniums
Cut back by half, remove dead leaves, and bring them inside.
Place on a bright windowsill, heated greenhouse, or conservatory.
Water sparingly to avoid rot.

B. Dormant Storage Method

Best for: Larger numbers or limited space
Uproot entire plants, shake off soil, trim to 10–15cm, and store in a cool, dry location (7–10°C) like a shed or garage.
Hang them upside down in paper bags or place in trays lined with newspaper.
Mist lightly every few weeks.

C. Take Geranium Cuttings

Take 10cm cuttings from healthy stems.
Remove lower leaves, dip in rooting hormone, and pot up in seed compost.
Keep indoors on a bright windowsill and they’ll root in 3–4 weeks.

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4. Preparing Your Geraniums Before Moving Them Indoors

Step-by-Step Prep Checklist

Inspect for pests: Look for aphids, whitefly, or vine weevils.
Trim back: Cut stems down by about one-third to reduce stress.
Remove old flowers and yellow leaves.
Clean pots and tools to avoid spreading disease.
Label varieties if you grow different types.

This process helps reduce mould, pests, and disease while ensuring your plant uses less energy in winter.

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5. Where to Store Geraniums in Winter

Choosing the Right Location

Ideal places to overwinter geraniums:

Heated greenhouse
Bright indoor windowsill
Frost-free porch
Garage or shed with minimal moisture (for dormant storage)

Avoid anywhere damp or dark. Mould and rot are major threats during winter.

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6. Watering Geraniums During Winter

Less Is More

Overwatering is a common mistake when overwintering geraniums.

For growing plants indoors: Water lightly once the top inch of compost is dry — every 10–14 days is often enough.
For dormant plants: A light mist every 3–4 weeks to prevent drying out is all that’s needed.

Avoid soggy compost as it promotes root rot and fungal disease.

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7. Common Issues with Overwintered Geraniums

Watch Out For:

Leggy growth: Caused by low light. Pinch back in spring.
Yellowing leaves: Overwatering or poor ventilation.
Mould on stems: High humidity or not enough airflow.
Pests: Use organic sprays or insecticidal soap if necessary.

Proper care and regular checking helps keep your plants healthy throughout the season.

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8. When to Move Geraniums Back Outside in Spring

Once night temperatures consistently stay above 10°C (usually around mid to late April in the UK), you can start hardening off your plants.

Hardening Off Steps:

Move outdoors for 1–2 hours a day, increasing over 7–10 days.
Keep them sheltered from wind and heavy rain.
Repot if needed and begin feeding with a liquid fertiliser.

Once fully acclimatised, they’re ready to bloom again outdoors!

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9. Benefits of Overwintering Geraniums

Keeping your geraniums alive through winter has many advantages:

Budget-friendly: No need to buy new plants each spring.
Earlier blooms: Established plants flower faster.
Environmental benefit: Less plastic pot waste and plant imports.
Sentimental value: Keep your favourite varieties alive year after year.

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10. Best Varieties of Geraniums to Overwinter in the UK

Some types cope better with overwintering:

Zonal Geraniums (Pelargonium x hortorum) – very common and robust.
Ivy-Leaved Geraniums (Pelargonium peltatum) – great for baskets, trail well indoors.
Scented-Leaf Geraniums (Pelargonium graveolens) – ideal for indoor overwintering.
Regal Geraniums (Pelargonium grandiflorum) – beautiful but more delicate, best indoors.

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Conclusion: Enjoy Your Geraniums Year After Year

Keeping your geraniums alive through the UK winter isn’t as difficult as it sounds. Whether you choose to bring them indoors, store them dormant, or take cuttings, a bit of autumn effort means you can enjoy bigger, better plants next year — without the cost of starting over.

With the right overwintering method, your pelargoniums will bounce back in spring, ready to brighten up your garden once again. So grab your snips, prep your pots, and give your geraniums the cosy winter care they deserve!

Top 10 FAQs: How to Keep Geraniums Alive in Winter

1. Can I leave my geraniums outside in winter in the UK?

No. Geraniums are tender and will die in frost. Always bring them inside or store them properly.

2. What temperature is too cold for geraniums?

Anything below 5°C risks damage; below 0°C can kill the plant.

3. Should I prune my geraniums before bringing them inside?

Yes, reduce the plant size by one-third to help it adjust and save space.

4. Can I overwinter geraniums in a garage?

Yes, if it’s frost-free and not damp. Ideal for dormant storage.

5. Do I water dormant geraniums?

Lightly mist every few weeks, but don’t soak them.

6. How do I know if my overwintered geraniums are still alive?

Scratch a stem with your nail — green underneath means it’s alive.

7. Can I overwinter trailing geraniums too?

Yes. Ivy-leaved varieties can be kept indoors or cut for propagation.

8. What’s the easiest method for overwintering?

Taking cuttings is space-saving, while storing whole plants is better for larger quantities.

9. When should I start feeding overwintered geraniums again?

Start feeding in early spring once new growth appears and plants are moved outside.

10. Can I use a windowsill to overwinter geraniums?

Yes — it’s a great option as long as it’s bright and warm enough.