Hardy Geranium
Geranium macrorrhizum · CranesbillUSDA | Grow Zone
3-8Outdoors all year in zones 3 to 8. Anywhere colder, keep it as a houseplant. Protect it below 40°F.
- Light
- Full sun to partial shade
- Water
- When top inch is dry
- Humidity
- 40-60%
- Temperature
- 60-75°F (15-24°C)
- Difficulty
- Beginner
- Growth
- Moderate
- Mature size
- 12-18 in tall, 18-24 in wide
Geranium macrorrhizum, commonly known as Hardy Geranium or Cranesbill, is a resilient perennial known for its vibrant blooms and lush foliage. Native to the mountainous regions of Europe, it thrives in various conditions, making it a popular choice for gardens.
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Ideal temperature
60-75°F is where it grows fastest. Below 40°F cold damage starts.
Spacing and harvest
- Mature size
- 12-18 in tall, 18-24 in wide
- Plant apart
- 18-24 in
- Frost
- Hardy: survives frost
Everything it needs
9 essentials at a glance
Watering
Geranium macrorrhizum prefers moderate watering.
Water the plant deeply when the top inch of soil feels dry, typically every 1-2 weeks. In the summer, you may need to increase frequency due to higher evaporation rates. Signs of over-watering include yellowing leaves and root rot, while under-watering can cause wilting and browning leaf edges.
Light
This plant thrives in full sun to partial shade, ideally receiving 4-6 hours of direct sunlight each day.
It can tolerate some shade, especially in hotter climates, but too much shade may reduce flowering. A location with morning sun and afternoon shade is often ideal.
Soil
Geranium macrorrhizum prefers well-draining soil with a pH range of 6.0 to 7.0.
A mix of loamy soil and organic matter, such as compost, is ideal. Ensure good drainage to prevent waterlogging, which can lead to root rot.
Humidity
This hardy geranium prefers moderate humidity levels, around 40-60%.
To increase humidity, consider misting the plant or placing a tray of water nearby. Signs of low humidity stress include browning leaf tips and wilting.
Temperature
The ideal temperature range for Geranium macrorrhizum is 60-75°F (15-24°C).
It is hardy in USDA zones 3-8, tolerating cold winters and moderate heat. Protect from extreme heat and frost to ensure healthy growth.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10, applied every 4-6 weeks during the growing season.
In fall, reduce feeding as the plant enters dormancy. Signs of nutrient deficiency include stunted growth and pale leaves.
Pruning
Prune back spent flowers and any dead or damaged foliage in late spring to encourage new growth and flowering.
Use clean, sharp pruning shears to avoid damaging the plant. Deadheading can promote more blooms throughout the season.
Repotting
Repot Geranium macrorrhizum every 2-3 years or when it becomes root-bound.
Choose a pot that is 1-2 inches larger in diameter. Signs it needs repotting include roots growing out of the drainage holes or stunted growth. Gently remove the plant from its pot, trim any damaged roots, and place it in fresh soil.
Propagation
Propagation can be achieved through division or seeds.
For division, do this in spring or fall when the plant is actively growing. Carefully dig up the plant, separate the root clumps, and replant them in well-draining soil. For seeds, sow them in spring after the last frost, covering lightly with soil.
When it's unhappy
Yellow leaves
Why it happens
Often caused by over-watering or poor drainage.
How to fix it
Ensure the soil drains well and adjust your watering schedule.
Root rot
Why it happens
Excess moisture in the soil leading to fungal infections.
How to fix it
Improve drainage and reduce watering frequency. Remove affected roots.
Wilting leaves
Why it happens
Under-watering or extreme heat.
How to fix it
Water the plant thoroughly and ensure it is in a suitable location.
Pest infestations (aphids, spider mites)
Why it happens
High humidity and poor air circulation can attract pests.
How to fix it
Regularly inspect the plant and treat with insecticidal soap if necessary.
Poor flowering
Why it happens
Insufficient sunlight or nutrient deficiency.
How to fix it
Ensure the plant receives adequate sunlight and fertilize appropriately.
Care through the year
Spring
In spring, prune back any dead foliage and fertilize with a balanced fertilizer to promote growth. Water regularly as the plant wakes up.
Summer
During summer, ensure consistent moisture, especially in dry spells. Deadhead spent flowers to encourage more blooms.
Fall
In fall, reduce watering as the plant prepares for dormancy. Cut back foliage after the first frost to tidy up the garden.
Winter
In winter, protect the plant from extreme cold by mulching around the base. Avoid over-watering during this dormant period.
Toxicity & Safety
Geranium macrorrhizum is non-toxic to pets and children. It is safe to have around cats and dogs, with no known harmful effects from ingestion.
Good to know
How often should I water my Hardy Geranium?
Water your Hardy Geranium when the top inch of soil feels dry, typically every 1-2 weeks. Adjust frequency based on weather conditions.
What type of soil is best for Geranium macrorrhizum?
Geranium macrorrhizum thrives in well-draining soil with a pH between 6.0 and 7.0. A mix of loamy soil and organic matter is ideal.
Why are my Hardy Geranium's leaves turning yellow?
Yellow leaves can indicate over-watering or poor drainage. Check the soil moisture and ensure the pot has adequate drainage.
Can I grow Geranium macrorrhizum in shade?
Yes, while it prefers full sun, it can tolerate partial shade. However, too much shade may reduce flowering.
When is the best time to prune Hardy Geraniums?
Prune back spent flowers and damaged foliage in late spring to encourage new growth and more blooms throughout the season.
How can I propagate Geranium macrorrhizum?
You can propagate by division in spring or fall or by sowing seeds in spring. Ensure to plant in well-draining soil.
What pests should I watch out for on my Hardy Geranium?
Common pests include aphids and spider mites. Regularly inspect your plant and treat with insecticidal soap if needed.
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