Regal geranium
Also known as
Martha Washington geranium, Lady Washington geranium, Show geranium, Pansy geranium
Keep this plant’s care guide close at hand.
Get the appAbout Regal geranium
Pelargonium grandiflorum, commonly sold as the Regal geranium, is a woody-based, compact subshrub native to South Africa’s Cape region. It is prized for its large, pansy-like blooms with ruffled petals and dark blotches, flowering most heavily in cool spring to early summer conditions. Leaves are medium to dark green, scalloped, and softly textured, often releasing a light, resinous scent when touched. Unlike zonal geraniums (Pelargonium × hortorum), Regals demand bright light paired with cooler temperatures to set buds and sustain flowering; they are notably intolerant of heat and waterlogged roots. Plants stay dense and floriferous with regular pinching and careful feeding that emphasizes phosphorus and potassium over nitrogen. In containers, a sharply draining, slightly acidic mix and excellent air circulation help prevent botrytis and edema. Though sometimes grown as seasonal color, well-tended plants can be kept for years, with a light rest in winter. While generally harmless to people, foliage may cause mild skin irritation in sensitive individuals, and ingestion can upset pets.
Taxonomy
Properties & Requirements
How to care for Regal geranium
Water
Allow the top 2–3 cm (about 1 inch) of the potting mix to dry before watering thoroughly until a little drains out. Empty saucers promptly. In cool, bright spring when plants are budding and blooming, maintain steady, even moisture without saturation. Reduce frequency in winter or during heat spells when growth slows. Always water at the base to keep foliage and petals dry, minimizing botrytis. If leaves blister (edema), lengthen intervals and improve drainage and airflow.
Light
Give bright light with 4–6 hours of gentle direct sun, ideally morning sun with dappled or bright indirect light later. Indoors, an east or bright south window is suitable; in hot regions, filter harsh afternoon sun to prevent leaf scorch and heat stress. Too little light reduces flowering and causes lanky growth; too much midday sun in heat can crisp petals. Rotate pots regularly for even growth and bud development.
Nutrients
Feed during active growth and bud formation with a balanced or bloom-leaning fertilizer (for example 10‑15‑10 or similar) at half-strength every 2–4 weeks. Keep nitrogen modest to avoid leafy, bloom-poor growth. Ensure micronutrients (especially iron and magnesium) are available in peat/coir-based mixes. Periodically flush the pot to prevent salt buildup, particularly when using synthetic fertilizers. Pause or reduce feeding in mid-summer heat and in winter rest. Resume as days lengthen and buds initiate under cool, bright conditions.
Temperature
Ideal temperatures are cool to moderate: days 15–21 °C and nights 7–13 °C promote bud initiation and sustained bloom. Brief dips to 5 °C are tolerated, but protect from frost. Prolonged heat above 27 °C can halt flowering and stress plants; provide afternoon shade and excellent airflow in hot climates. Overwinter bright and cool, around 8–12 °C with lighter watering. Avoid sudden swings; steady, cool conditions yield the best flower performance.
