How to Overwinter Zonal Geraniums | Pelargoniums

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Secrets from My Favourite Gardener

Geraniums (Pelargonium x hortorum), also known as zonal geraniums, are very easy to store for the winter. You can either continue growing them as houseplants (if you have room) or let them go dormant for a few months in storage and then repot them for spring.

Recently my mom (a.k.a. my favourite gardener) shared her tips for growing orchids and today we’re looking at different ways to keep geraniums going through the cold months (including her tried-tested-and-true newspaper method).

While storing the plants for winter is only somewhat frugal (geraniums are not exactly expensive), my top reason for hanging onto geraniums is colour. Some years I find them in particularly gorgeous colours and, knowing I might not be able to find that colour again next year, I hoard what I have.

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How to Tell Zonal and Seed Geraniums Apart

There are over 800 species of geraniums so it is not unusual to mix them up! It also does not help that the word ‘geranium’ is used for cranesbill and zonal geraniums.

Pelargoniums are zonal geraniums (not ‘seed geraniums’) and can live perennially if temperatures do not drop below about 45F (7C). Their sweet spot is between 55-65F (12-18C) so keep this in mind when deciding where to stash them for the winter.

Zonal geraniums

• Have a dark band of colour on their leaves—that’s the ‘zone’ of ‘zonal’.
• Are taller, more robust with thicker leaves, and hardier than seed geraniums.
• Get double flowers while seed geraniums produce singles (although a lot of them).

Seed geraniums

• Are smaller plants overall and have smaller bloom heads than zonal geraniums.

If you want to be fruitful and multiply, see the instructions at the bottom of this post for propagating geraniums from cuttings.

More About Geraniums | Wikipedia

• The Geraniaceae family of flowering plants comprises 830 species, including the most important genera are Geranium (430 species), Pelargonium (280 species) and Erodium (80 species).
• Cultivated pelargoniums are commonly treated as six groups:
  Zonal (Z), Ivy-leaved (I), Regal (R), Angel (A), Unique (U), Scented-leaved (Sc), Species
• Pelargonium × hortorum (Zonal) are known as zonal geraniums because many have zones or patterns in the center of the leaves.
  Zonal pelargoniums are mostly bush-type plants with succulent stems grown for the beauty of their flowers, traditionally red, salmon, violet, white or pink.

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Get Ready

Preparation for Overwintering Zonal Geraniums
No matter which method you choose, the initial preparation is the same. The goal is to nurture healthy plants, prevent the spread of disease, and reduce the chance of bringing unwanted insects along for the ride.It’s best to do this before the really cold weather has set in so the transition from outdoor to indoor living is relatively seamless.
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1. Set up a work table and have clean pruners ready.
2. Dig up your geraniums.
3. Sort them by colour (if you want to keep track).
4. Gently shake off any loose soil from the roots.
5. Remove any dead leaves, flower heads and buds.
6. Check for aphids, spider mites, fungal gnats, and other sneaky beasts.
You may want to spray the plant with a homemade dormant spray (recipe below) to be sure you’ve got the little whippersnappers.
7. Clip off any moldy or rotted areas with clean pruners.

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After the basic preparation, we can go in one of two directions.1. Repot the plants and keep them as houseplants over the winter.
or
2. Let them go dormant until it’s time to pot them up in late winter/early spring.

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5 Options for Overwintering Zonal Geraniums

1. Super Simple Overwintering Garage Method
If you want a really quick method and don’t mind a higher risk of the plants dying, here’s what to do.
Give your potted geraniums a good drink of water, remove any dead (easy to pull) leaves, mold, or rotted areas, and stash them in a cold (not below freezing) garage. Done!
Water lightly every now and then and start reintroducing them to regular watering and light in the spring.
Lots of people use the super simple method year after year without any problems. I’ve found it a bit hit and miss. Some years they get really moldy and die, other years they just wither a bit and perk up in the spring.

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2. Overwintering Zonal Geraniums (Pelargoniums) as Houseplants
I see a lot of varying advice about the best indoor growing conditions. I had geraniums growing indoors in my living room for years. They faced a northwest window and just got direct sun (tops of the plants only) in late afternoon. They bloomed and rebloomed endlessly.
Others advise warmth and a fair amount of sun. I’m guessing the bottom line is, it will depend on the individual plants and how adaptive they are.
1. Do the prep work listed above.
2. Cut the plants down by one third. Clip just above leaf nodes. This will encourage new growth and flowering.
3. Repot the geraniums in fresh container mix suitable for this type of plant.
4. Water thoroughly.
5. Bring indoors.
6. To maintain them, remove any dry or dead parts and water modestly (they don’t like bone dry soil or damp).

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Indoor Dormant Methods

3. Paper Bag Method
1. Do the prep work listed above.
2. Label each bag with plant name and colour of flowers.
3. Place each plant upside-down in paper bag with the roots sticking out.
4. Gently tie bag shut with string.
5. Hang bag up in basement or garage (cannot go below 50F/10C).
6. Check plants monthly for any signs of mold or rot. Remove affected areas.
7. After a few months (late winter), it’s time to pot them in fresh container mix, water, and reintroduce to light. This video shows the paper bag method:

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4. Cardboard Box Method
1. Do the prep work listed above.
2. Label each box with plant name and colour of flowers.
3. Place each plant upside-down in large cardboard box with the roots facing up.
You can put several plants in each box but do allow room for air circulation.
4. Fold box tops shut (but allow air gaps).
5. Store in basement or garage (cannot go below 50F/10C).
6. Check plants monthly for any signs of mold or rot. Remove affected areas.
7. After a few months (late winter), it’s time to pot them in fresh container mix, water, and reintroduce to light.
Video: http://www.gardengatemagazine.com/overwinter-geraniums/

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5. Mom’s Newspaper Method
1. Do the prep work listed above.
2. Label each bag with plant name and colour of flowers.
3. Wrap the roots of each plant in a sheet of newspaper and place them in an open plastic bag.
4. Water the newspaper until damp (not soaking wet).
5. Hang bag in basement or garage (cannot go below 50F/10C).
6. Check plants monthly for any signs of mold or rot. Remove affected areas and water newspaper if becoming dry.
7. After a few months (late winter), it’s time to pot them in fresh container mix, water, and reintroduce to light.
This video shows the paper bag and cardboard box methods:

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Grow New Plants from Cuttings

• Have a small pot and moist container mix ready.
• From a healthy geranium plant, choose a stem that appears green (not woody).
• Just above some leaf nodes, snap off approximately 4 inches from a stem.
• Remove any leaves from the bottom 2″.
• Keep the remaining leaves attached.
• Dip the base in rooting hormone. Tap off any excess powder. They guy in the video uses honey.
• Use your finger or a dibber to make a hole in the container mix and insert the geranium stem. Careful not to push the rooting hormone powder away. Loosely fill hole with container mix.
• You can put several cuttings in one pot. Just leave room for a bit of root growth.
• Water gently.
• Loosely place plastic bag over top to retain humidity but allow air flow.
• Keep in warm location. Avoid full sun until roots have formed (it usually takes a few weeks).
• Keep container mix moist but not soaking wet.
• Roots forming? After a few weeks, gently tug on one of the plants to see if it’s grabbing hold.
  If so, repot into single containers.

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Getting Overwintered Geraniums Ready for Spring

No matter which method you followed, by late winter it’s time to have the plants in pots with fresh container mix, ready for gradual reintroduction to light and regular watering.

When the risk of frost is passing, you will start ‘hardening off’ your geraniums by gradually introducing them to outdoor conditions where you can enjoy them outdoors all summer long.

~Melissa the Empress of Dirt ♛