Growing Regal Geraniums: The Complete Guide

1. Understanding Regal Geraniums

Regal geraniums are hybrids bred for their extravagant flowers, which often feature bold bi-colored petals and intricate markings. Unlike the common zonal geranium, regals prefer cooler growing conditions and bloom most heavily in spring and early summer.

Key traits:

Botanical name: Pelargonium × domesticum

Bloom period: Late winter to late spring (indoors) or spring to early summer (outdoors).

Height & spread: 12–24 inches tall and wide.

Fragrance: Mild scent in leaves when crushed.

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2. Choosing How to Grow Them

You can start regal geraniums from:

Nursery plants (most common).

Cuttings from an existing plant.

Seeds (less common — hybrids may not come true to type).

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3. Ideal Planting Time

Outdoors: Plant after the last frost date in your area.

Indoors: Can be started at any time with adequate light.

In most climates, they are treated as annuals, but in frost-free regions (USDA zones 10–11), they can be grown year-round.

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4. Light Requirements

Indoors: Bright, indirect light; a south- or west-facing window is ideal.

Outdoors: Full sun to light afternoon shade; too much intense midday sun can scorch flowers and leaves.

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5. Soil Preparation

Regal geraniums thrive in loose, well-draining soil.

For containers:

Use high-quality potting mix with added perlite or coarse sand.

Avoid heavy garden soil, which holds too much moisture.

For garden beds:

Amend with compost and grit for drainage.

Aim for a pH between 6.0 and 6.5.

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6. Planting in Pots

Choose a 12–14 inch container with drainage holes.

Fill with potting mix, leaving 2 inches at the top.

Plant so the crown is at soil level.

Water lightly to settle soil.

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7. Watering Needs

Regal geraniums dislike soggy soil but also shouldn’t dry out completely during bloom.

During active growth: Water when the top inch of soil feels dry.

After flowering: Reduce watering as plants rest.

Container tip: Check daily in hot weather, as pots dry faster.

Always water at the base to avoid wetting foliage, which can lead to fungal problems.

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8. Fertilizing Schedule

Feed every 2 weeks during the blooming season with a high-phosphorus fertilizer (e.g., 10-20-10) to promote flowers.

Stop fertilizing after the bloom period ends to allow the plant to rest.

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9. Temperature & Humidity

Best bloom temperature: 60–70°F (15–21°C) during the day and 50–55°F (10–13°C) at night.

Hot weather can halt blooming; in summer, move containers to a cooler, shaded location if possible.

Avoid overly humid areas, which can encourage disease.

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10. Deadheading & Pruning

Deadhead spent blooms promptly to encourage new buds.

Remove yellowing leaves regularly to improve airflow.

After blooming, cut back stems by one-third to maintain shape and encourage bushy growth.

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11. Pest & Disease Prevention

Common pests:

• Aphids
• Whiteflies
• Spider mites

Common diseases:

• Botrytis (gray mold)
• Root rot (from overwatering)
• Rust

Prevention tips:

• Provide good airflow.
• Water early in the day.
• Use insecticidal soap or neem oil for pests.

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12. Encouraging a Full, Dome Shape Like in Your Photo

Pinch back stem tips regularly in early growth to encourage branching.

Rotate the pot weekly so all sides receive equal light.

Avoid overcrowding; one plant per medium pot gives best results.

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13. Blooming Cycle & Rest Period

Regal geraniums naturally bloom in spring and early summer. After flowering:

Reduce watering.

Keep in a cool location (50–55°F) for 6–8 weeks.

Resume normal care to trigger a second bloom cycle in cooler weather.

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14. Overwintering

If you live in a frost-prone area:

Bring pots indoors before the first frost.

Place in a bright, cool location.

Water sparingly until spring growth resumes.

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15. Propagation by Cuttings

In late summer, cut 4–6 inch non-flowering shoots.

Remove lower leaves and dip the cut end in rooting hormone.

Plant in moist, sterile potting mix.

Keep in bright, indirect light until rooted (about 4–6 weeks).

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16. Design & Companion Ideas

Pair regal geraniums with plants that like similar conditions:

• Lobelia
• Petunias
• Verbena

Their upright, domed form makes them perfect as a container centerpiece or in window boxes.

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17. Annual Care Calendar for Regal Geraniums

January–February

• Indoors: Maintain cool temps and bright light.
• Check for pests.

March–April

• Begin fertilizing.
• Move pots outdoors after frost danger passes.

May–June

• Peak bloom period; deadhead often.

July–August

• Move to a cooler, shaded location if heat is intense.

September–October

• Take cuttings for next year.
• Begin reducing water.

November–December

• Overwinter indoors in cool, bright location.

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🌟 Final Tips

Regal geraniums are not heat lovers, so their spectacular blooms are best in spring-like conditions.

The lush dome shape in your photo comes from consistent pinching, even light, and no overcrowding.

Treat them as seasonal showpieces — a few months of stunning flowers, followed by rest and careful maintenance, can give you years of beauty.

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