Geranium, zonal (Pelargonium x hortorum)

Encyclopedia Article

zonal geranium

Pelargonium x hortorum

Image of Pelargonium x hortorum (annual geranium) red happy thought
Geranium 'Red Happy Thought'

Family: Geraniaceae

Size: 1—3’ tall; 1—3’ wide

Hardiness: Zones 10 — 11

Leaves: rounded orb to kidney-shaped leaves that often have darker horseshoe-shaped zonal bands.

Leaf Color: medium green

Flowers: long flowering stalks hold five-petaled umbels. The stamens often transform into petals and look like double flowers. Come in various shades of red, purple, pink, orange and white.

Fruit: dry, needle-like projections protrude from the fruiting head and resemble the beak of a stork

Habit: have a shrub-like mound shaped habit with longer flowering stalks that protrude above.

Stem: longer flowering stems rise out of the mound of foliage.

Nativity: garden origin

Insects & Disease Issues: Stem and root rot can develop from poorly drained soil. Susceptible to leaf spot and gray mold. Insects like caterpillars, whiteflies and aphids may appear.


Culture and Uses:

These classic garden annuals can be grown outdoors during the growing season and easily overwintered indoors year after year.  Grow in full to part sun in moist, well drained soils.  They do exceptionally well in containers and the large red, pink or white flower clusters are show stoppers.  Deadhead by snapping spent flower stalk off at the base—this improves appearance and promotes rebloom.  Pinch back stems to promote bushy growth habit. Plants appreciate regular fertilizer during summer months.  Plants can be overwintered as a houseplant in a bright indoor space.  Overwintering as dormant plants in another option.  Just before killing frost, pull plants, remove soil from roots and store in a cool place.  Keep roots marginally moist (not wet!) and six weeks before last spring frost, soak roots overnight and repot.  Plants propagate easily from cuttings or from seed.  Sow seed indoors 4 months before last spring frost. 

Notable Cultivars & Related Species: 

Dozens of cultivars have various colors and flower sizes.

Scented geraniums have leaves that are fragrant with scents including lemon, nutmeg, chocolate and peppermint.

P. peltatum (ivy geranium) - trailing stems and glossy ivy-shaped leaves

Image of Pelargonium x hortorum (annual geranium) Waltz Time
Geranium 'Waltz Time'