Bitter Orange (Citrus aurantium)

Bitter Orange

Citrus aurantium

Fragrant blossoms and glossy leaves bring Mediterranean warmth. Evergreen fruiting shrub/tree; common names: Seville orange, bitter orange.

Full sun
1–2/week
Moderate
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Plant Needs

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Sunlight Requires 6–8 hours of direct sunlight daily for optimal fruiting; tolerate partial shade in extremely hot climates to prevent leaf scorch
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Watering Water deeply when the top 5–7 cm of soil dries out; avoid overwatering to prevent root rot and fungal diseases
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Temperature Thrives in 15–28°C; tolerates mild frost down to 5°C but requires protection from hard freezes to avoid branch damage
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Characteristics

  • Leaf: Glossy, ovate to elliptical leaves with winged petioles; dark green upper surface, lighter underside
  • Flower: White, fragrant, star-shaped blossoms with 5 petals; clustered at branch tips
  • Fruit: Round, orange-colored fruit with thick, bitter peel; pulp is acidic and not typically eaten raw
  • Stem: Woody, thorny branches with smooth, light brown bark
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Care Guide

Watering

Keep soil consistently moist but not waterlogged; increase watering frequency during hot, dry spells

Fertilization

Apply balanced, slow-release fertilizer every 4 weeks. Do not fertilize during winter dormancy to prevent nutrient buildup

Banana peel compost tea:Compost banana peels for 2–3 weeks, steep in water for 24 hours, dilute 1:20, and apply as a root drench to promote fruiting and leaf health
Pruning
  • Prune in late winter to remove dead, diseased, or crossing branches and improve air circulation
  • Thin overcrowded growth to allow sunlight to reach inner branches and support fruit production
  • Remove suckers from the base regularly to maintain the tree's desired shape and direct energy to main branches
  • Trim back overly long branches to control size, especially for container-grown specimens
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: Toxic; contains essential oils and psoralens that may cause vomiting, diarrhea, and depression

Humans: Ingestion of large amounts of peel or fruit may cause gastrointestinal upset; concentrated essential oils may irritate skin

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Garden Uses & Culture

Culture: Associated with traditional herbal medicine and used to flavor liqueurs like Curaçao; symbolizes warmth and abundance in Mediterranean folklore

Usage: Thick, bitter peel used in marmalades and essential oil production; ornamental tree for garden screening and fragrance