Zonal geranium

Sun

Full sun; afternoon shade helps in very hot climates.

Water

Water thoroughly, then let the surface soil dry before watering again. Water sparingly during cool indoor overwintering.

Soil

Well-drained soil of average fertility; use free-draining potting mix in containers.

Height

1-3 ft (0.3-0.9 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Late spring to autumn, sometimes longer in frost-free climates; red, pink, salmon, orange, white and bicolours.

Foliage

Evergreen. Rounded, softly hairy, scalloped leaves, often with a darker horseshoe-shaped band; some selections have bronze or variegated foliage.

Growth

Fast during warm weather

Care needed

Medium

• Plant outdoors after frost risk has passed and the weather has warmed.
• Use containers with drainage holes and empty water-filled saucers.
• Water at soil level when the surface has dried; avoid keeping the roots constantly wet.
• Feed container plants with a balanced liquid fertiliser every two to four weeks during active growth, following the label.
• Remove spent flower stalks and yellowing leaves regularly.
• In cold regions, bring selected plants into a bright, frost-free place before the first frost.

Pruning. Pinch young shoot tips in spring to encourage branching. Shorten leggy stems by up to half in early spring as growth resumes, cutting just above a leaf joint.

Early spring

Trim overwintered plants, refresh their potting mix and gradually increase watering as new growth appears.

Late spring

Harden off indoor plants and plant outside after the last frost.

Summer

Deadhead, check container moisture regularly and feed actively growing plants.

Late summer

Take cuttings from healthy, non-flowering shoots to keep young plants for next year.

Autumn

Move plants you want to keep into a bright, frost-free position before frost arrives.

Winter

Keep overwintering plants cool and bright, water sparingly and inspect for pests.

• Use upright plants in terracotta pots beside sunny doors or steps.
• Repeat one flower colour through window boxes for a unified frontage.
• Plant in blocks along sunny bedding borders for summer colour.
• Combine with trailing verbena and silver-leaved plants in containers, keeping the geranium as the upright centre.

Garden styles it suits: Traditional, Victorian, Mediterranean, Modern courtyard, Cottage garden and Small-space.

Plant it with: Trailing verbena, Dusty miller, Sweet alyssum, Blue salvia and Dichondra.

Wildlife: Open, single flowers can attract visiting insects, but zonal geraniums are not a particularly rich nectar source. Double-flowered forms offer less accessible food.

• Geranium rust causes yellow leaf spots and rusty pustules underneath: remove affected leaves, improve airflow and avoid wetting foliage; discard badly affected plants.
• Grey mould develops on flowers and leaves in damp, crowded conditions: remove dead material promptly, space plants apart and keep foliage dry.
• Whiteflies and aphids weaken shoots, especially indoors: inspect leaf undersides and treat with insecticidal soap labelled for the pest and plant.
• Root or stem rot follows persistently wet compost: improve drainage, allow the surface to dry between waterings and discard plants with soft, blackened stems.

Leaves, stems and flowers contain compounds toxic to cats and dogs; chewing them may cause vomiting, poor appetite, lethargy or skin irritation. Horse toxicity is not well established, so keep plants out of their reach. In people, sap can irritate sensitive skin; the plant is not intended for eating.

• Ivy-leaved geranium (Pelargonium peltatum)

  Has trailing stems and smoother, glossy, ivy-shaped leaves rather than the zonal geranium's usually upright growth and softly hairy, rounded leaves.

• Regal pelargonium (Pelargonium × domesticum)

  Usually has larger, showier flowers with strongly marked upper petals and more sharply toothed leaves.

• Hardy geranium (Geranium spp.)

  Usually has more deeply divided leaves and individual, evenly shaped five-petalled flowers rather than dense rounded clusters; many are frost-hardy.

Pelargonium comes from the Greek for stork, referring to the beak-like fruit, hortorum means 'of gardens', and 'zonal' describes the darker band often visible on the leaves.

Propagation. Take non-flowering stem cuttings in spring or late summer. Remove lower leaves and insert into free-draining propagation mix, keeping it lightly moist rather than wet. Seed is suitable for seed-raised strains, but saved seed may not resemble the parent.

Accepted botanical name

Pelargonium hortorum

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.