Grow and Care for Hardy Geranium

The word geranium covers two plants. Hardy cranesbill (genus Geranium) stays in the ground through winter. Bedding “geranium” is usually Pelargonium — frost-tender pots. This page is hardy Geranium only. Full sun to part shade depends on type. Drain the crown. Shear after the main flush. Sort types on Types of Hardy Geraniums.

Hardy cranesbill — confirm it is not a pelargonium

The Spruce / Garden Design: hardy geraniums are true perennials, often about USDA zones 3–9 by species. Pelargonium is a different genus, hardy only in the warmest belts and usually grown as an annual pot. If the tag says geranium but the plant is a zonal or ivy-leaf window-box, you are not on this page. Check the Latin name.

Pets: some references treat hardy geranium as a problem if chewed. Keep grazing pets off the clump. That is separate from drainage. A wet crown still rots whether or not a dog is nearby.

Site and soil — sun to part shade by type

Match the type before you copy a neighbor’s site. Long-bloom hybrids such as Rozanne want open light and room to sprawl. Bloody mats such as Max Frei suit sunny edges. Bigroot carpets such as Bevan’s Variety tolerate drier shade under shrubs. Woodland types such as Samobor prefer cooler part shade. Alpine cinereum such as Ballerina need sharp drainage at a rock edge. In hot summers (Missouri Botanical Garden on Rozanne), afternoon shade keeps bloom going.

Plant so the crown sits at ground level or slightly above. Iowa State and Illinois Extension: moist, well-drained soil; not a winter puddle. Amend clay so water leaves. Mulch the soil, not the stems. Steady water while plants establish. Many types then take short dry spells. Crowns that stay soggy invite rot and mildew.

Shear after flush and seasonal rhythm

Most hardy geraniums have wispy stems that are tedious to deadhead one by one. After the main flush, shear spent stems and tired foliage — often by a third to half, or closer to the ground on a tired mound. Fresh leaves follow; a later bloom often does too. Bigroot and cantabrigiense carpets need only a light tidy; they hold foliage. Rozanne-class plants that bloom for months may need less of a hard cut — trim side stems if they roam.

• Spring. Tidy winter damage. Plant or divide in cool soil. Water as growth starts.
• After the first flush. Shear. Feed lightly if the soil is poor. Watch for mildew in still, wet air.
• Late summer / fall. A second divide window while roots can still settle. Light mulch after the soil cools in cold gardens.
• Congested clumps. Split on Dividing Hardy Geraniums.

Continuous bloomers live on Long-Blooming Hardy Geraniums. Partners live on Hardy Geranium Companion Plants.

Growing hardy geraniums in containers?

This is a tip only, not a full pot program. Compact types such as Max Frei and Ballerina can work in a wide, well-drained pot with the same sun-or-shade-by-type rules. Water so the crown never sits wet. Long trailing hybrids such as Rozanne need room to sprawl — a large trough or open ground usually looks better. Do not treat hardy Geranium pots as frost-tender Pelargonium bedding you discard each fall.