4 Easy Ways to Overwinter Geraniums

Overwintering Geraniums

Gardeners have all sorts of ways to keep geraniums over the winter and regrow them in spring. I like to save particularly beautiful specimens, knowing I may not be able to find similar ones at plant nurseries next spring.

Some gardeners save them as family keepsakes, both overwintering the plants and taking rooting cuttings to ensure they survive for years.

There is some name confusion with these plants. The Geraniaceae family of plants includes Geranium (430 species), Pelargonium (280 species) and Erodium (80 species).

We commonly refer to Pelargoniums (Pelargonium x hortorum) as ‘geraniums’ but that’s actually another genus in the family. I’m using the two words interchangeably here.

Many Pelargoniums grow as bush-type plants with thick, succulent stems, which is why they are good candidates for winter storage.

The flowers are traditionally red, salmon, violet, white, or pink.

While they are sold as annuals, they are actually tender perennials, and tolerate temperatures down to about 45°F (7°C). Their sweet spot is between 55°-65°F (12°-18°C), which is ideal for indoor growing as well. 

Contents

4 Easy Ways to Overwinter Geraniums

1   Bring Inside as Houseplants

If you have room for the pots in a sunny location, you can bring your potted geraniums (Pelargoniums) into your house for the winter.

While they need sun, they do best with moderate temperatures  55°-65°F (12°-18°C). I have great success with a west-facing window that is slightly drafty, keeping the air around them a little cooler than the rest of the house. 

Dig Up and Repot if Desired

There is some preparation necessary to ensure they are happy, healthy, and insect-free.

• If your geraniums are in the ground, dig them up and pot them about six weeks before first frost.
• If they are already in pots, you can repot them if desired but hard prune and do your bug inspections first (see below).
• While potting, trim back any super long roots or any gnarly root balls.
• Use potting mix suited for flowering plants in containers.

Tag by Colour

• Sort your geraniums by colour and tag them if you want to keep track.

Hard Prune

• It is commonly advised to cut back the entire plant by one-third to one-half.
• You should also remove any dead, damaged, moldy, unhealthy, or diseased parts.
• While this hard pruning is best in the long run, you can try keeping any buds or flowers if the plant is otherwise nice and healthy.

Bug Inspection

• Check for aphids, spider mites, fungal gnats, and other sneaky beasts.
• Apply an insecticide made specifically for transitioning plants indoors.

Bring Inside

• Water moderately, and get your plants settled in a sunny but not hot location.

Winter & Spring Care

• Keep moist, not dry or damp.
• Mist of humidity is low.
• Pinch back shoots.
• Fertilize lightly in spring.
• Begin to harden off (prepare plants for life outdoors) a few weeks before last frost.

2   Take Cuttings

Instead of bringing the entire plant indoors for the winter, you can also take cuttings. This is a good solution if space indoors is limited, or you want more plants.

For step-by-step instructions, see How to Take Cuttings from Geraniums.

3   Cool Storage

I find this method is unreliable—some years the geraniums do fine, other years they don’t—but it’s not a bad choice if you just want an easy option and don’t mind if the plants die.

You’ll need a cold storage space like a garage, shed, cold cellar, or unheated basement that does not dip below freezing. It’s the soil temperature that matters and you can measure that with any simple kitchen thermometer like this one with a probe.

Clean up your potted geraniums by removing dead, damaged, moldy, diseased parts, and cutting the entire plant back by one-third to one-half.

Check and treat for insects.

Water deeply and place in storage.

I like to place some rods in the soil and hang a blanket over the whole thing.

Winter & Spring Care

• Check monthly or more often and remove any moldy or dead parts.
• Water lightly every now and then.
• In spring, gradually reintroduce to outdoor light and normal watering routine.

4   Dormant Bare Root Storage

This is a popular method that has been done for generations. You’ll need a garage, shed, cold cellar, or unheated basement that does not dip below freezing or go beyond 45°F.

We call it ‘bare root’ storage because the plant is removed from the soil, pruned, and placed in cool storage. Pelargoniums can handle this because of their thick, succulent roots, which survive so long as they do not dry out or become diseased.

Here’s what you do.

Label Your Plants by Colour

• First, plan to label your plants if you want to keep track of the flower colours.
  • You could store them in groups by colour or place tags (loosely) around their roots.
  • I write the details on little strips of cardstock and staple it like a wristband around the stems.

Dig Up or Unpot 

• Gently shake off all loose soil.
• You can air dry the plant for a few days and then shake off more soil.

Storage

Whatever you do, you don’t want the plants to get damp or sit on moisture because they are prone to mold.

You do, however need to keep them watered, and not allow them to dry out (they’ll die).

There are several options:

• Suspend the plants from ceiling hooks.
• Place in paper bags and hang from hooks or set on shelf.
• Wrap in newspaper and sit on shelf.
• Place in cardboard box.

As far as I can tell, the advice to always hang the plants upside-down for better results seems to be a wives’ tale.

Winter & Spring Care

• Check on your plants every week or two. I put a reminder in my computer calendar.
• The plants should remain firm, not withered or unhealthy looking.
• Remove any mold, black parts, or dead matter.
• Soak in warm water for one to two hours each month.
• Allow to dry before returning to bags, newspaper, or box.

Six Weeks Before Last Frost

Reviving Dormant Geraniums

• Prune as needed and remove any excessively long roots.
• Pot in moist potting mix, burying the plant two leaf nodes deep (these will form roots).
• Gradually re-introduce to light.
• New growth should appear in 1-2 weeks.
• Gradually introduce to life (harden) outdoors in anticipation of last frost.

Watch Geranium Tips

Resources

• Overwintering Geraniums | Iowa State University
• How to Take Geranium Cuttings | Thompson & Morgan
• How to Buy and Care for Pelargoniums | Oregon State University Extension Service

Frequently Asked Questions

1  Can I overwinter my geraniums in Canada? The United States? UK?

• Yes, it does not matter where you are, it matters what conditions you can provide during the colder seasons. With all options (listed above) so long as the plants do not freeze, they can survive the winter.

2  How to I winterize my geraniums indoors?

• You can keep them as houseplants, keep cuttings, or store the bare roots in a dry, cool location.

3  Can geraniums survive a freeze?

• No, geraniums (Pelargoniums) are tender perennials, hardy down to about 45°F.
• True geraniums (genus geranium) like cranesbill are hardy perennials.

4   Can I grow geraniums (pelargoniums) from cuttings?

• Yes, you can take cuttings any time in the growing season and root them for new plants.

~Melissa the Empress of Dirt ♛

Next

• How to Prepare a Garden Pond for the Winter
• How to Grow Vegetables in the Winter
• How to Keep Compost in the Winter