Perennial
How to grow hardy geraniums
Geranium species and hybrids
Hardy geraniums grow in almost any soil that drains, in sun or part shade, and are planted in March to May or September to October. Two things decide how good they look: matching the species to the spot, since some want sun and others thrive in dry shade, and shearing the whole plant to 5 cm after the first flush in late June so it comes back fresh and flowers again. They need very little feeding. They also earn a place in wildlife gardening, since bees work the open flowers.
- Hardiness
- Fully hardy
- Position
- Sun to part shade
- Soil
- Most soils; free-draining
- Ideal pH
- 6.0 to 7.5
- Water
- Low to moderate
- Feeding
- Light feeder
Sowing and planting hardy geraniums
WhenPlant Mar to May or Sep to Oct; flowers May to Sep
Starting off
Plant pot-grown plants Mar to May or Sep to Oct. Divide clumps in Mar or Sep every 3 to 4 years, teasing into fist-sized pieces with roots; the easiest method. Species seed sown Mar to Apr at 15 to 18 °C germinates in 14 to 30 days, but hybrids do not come true.
Spacing and planting
Plant 30 to 45 cm apart for ground cover; large types such as 'Rozanne' spread 90 cm; set the crown at soil level. Fine in a 30 cm pot for compact types.
Varieties worth growing
- 'Rozanne'
- Violet-blue with a white eye from June to the first frosts without a break; spreads 90 cm, so give it room or a large pot.
- G. macrorrhizum 'Bevan's Variety'
- The answer for dry shade under trees and hedges: dense, weed-proof, aromatic semi-evergreen leaves and magenta flowers in May.
- G. sanguineum var. striatum
- Low, neat mound 15 cm high with pale pink veined flowers; for the front of a sunny border, gravel or a pot.
- G. phaeum 'Samobor'
- Dusky maroon flowers in May over leaves blotched chocolate; happy in full shade and one of the earliest for bees.
- 'Orion'
- Large, clear blue flowers on a 70 cm plant; a stronger, longer-flowering replacement for 'Johnson's Blue'.
Hardy geraniums month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Nothing to do.
- February
Cut away last year's dead growth before new shoots start. Leave evergreen types alone.
- March
Light feed and mulch. Divide congested clumps. Plant new ones.
- April
Plant. Sow species seed. Put in twiggy supports for tall meadow types.
- May
First flowers on G. phaeum and G. macrorrhizum. Water spring plantings in a dry spell.
- June
Main flush. Shear early types to 5 cm in the last week and water once.
- July
Sheared plants regrow. 'Rozanne' in full flower; no cutting needed yet.
- August
Second flush on sheared plants. Cut sprawling 'Rozanne' back by half if it is swamping neighbours.
- September
Plant and divide while the soil is warm.
- October
Last planting. Leave the top growth as winter cover.
- November
Nothing to do. Some, such as G. macrorrhizum, colour red.
- December
Nothing to do.
Feeding hardy geraniums
A light feeder. One small spring feed is the most it needs in a border, and in decent soil a mulch alone will do. Feeding more gives floppy leaves and fewer flowers.
Tough and undemanding, a light spring feed only.
Feeding plan
March, borders
50 g/m², half the label's 100 g/m², scattered round the clumps and covered with a 3 to 5 cm mulch of garden compost. A plant at 45 cm spacing covers about 0.2 m², so 10 g each. Once only.
Late June, straight after shearing
1 g per litre of water, about 5 litres per square metre, as a single drench to help the regrowth. Repeat once after 2 to 3 weeks if the summer is dry.
March, pots
2 g per litre of compost scattered on the surface and watered in: about 24 g for a 30 cm pot holding 12 litres. Nothing later in the year.
Signs to watch
Few flowers and floppy growth
Nitrogen excess or shade
No feed, more sun
Leaves yellow with brown edges in a pot in Aug
Dry roots and potash short
Water and a high-potash feed
Centre of the clump dies out
Congestion after 4 years
Divide in Mar
Pests, diseases and problems
White powdery coating on leaves from July, plant looks tired
Powdery mildew on a dry-rooted plant after the first flowering
Shear the whole plant to 5 cm, water it once thoroughly and it regrows clean. Mulch in spring to hold moisture.
Plant in a pot wilts although the compost is moist, and lifts away with no roots
Vine weevil grubs eating the roots
Water on vine weevil nematodes in April and again in late August to September while the compost is above 5 °C; repot into fresh compost and pick out the white C-shaped grubs.
Small round holes scattered across the leaves in summer
Geranium sawfly larvae feeding on the undersides
Cosmetic. Tolerate it, or pick off the small grey-green larvae; the midsummer shear removes most of the damage.
Clump falls open from the middle after rain in June
Tall soft growth in rich soil or shade, typical of G. pratense and G. × oxonianum types
Do not feed. Push in twiggy sticks in April, or simply cut the plant to the ground when it flops and let it regrow.
Seedlings coming up all over the bed and in paving
Free self-seeding by G. × oxonianum, G. pratense and G. pyrenaicum
Shear straight after flowering, before the seed heads ripen and fire their seed. Sterile hybrids such as 'Rozanne' do not seed.
Pruning
Pruning and care
Shear the whole plant to 5 cm after the first flush in late Jun, water, and it regrows with fresh leaves and a second flowering in Aug. No staking; 'Rozanne' and sprawling types are tidied by cutting back by half in Aug. Cut dead growth away in Feb and divide every 3 to 4 years in Mar. Fully hardy, no protection.
Good to knowCut back after the first flush for fresh leaves and more flower; superb easy ground cover.
Growing hardy geraniums in pots
Compact types such as G. sanguineum var. striatum and G. cinereum 'Ballerina' suit a 30 cm pot; 'Rozanne' fills a 40 to 45 cm pot on its own and trails over the edge all summer. Use a loam-based or peat-free multipurpose compost with a fifth grit, and water when the top few centimetres are dry, which in July means every day or two. Pots are where vine weevil finds them, so check the roots if a plant suddenly wilts. Split and repot into fresh compost every two to three years in March.
Hardy geraniums: common questions
When should I cut back hardy geraniums?
Cut early-flowering types to about 5 cm in late June, as soon as the first flush fades, and they regrow within three weeks and flower again in August. Long-flowering 'Rozanne' is only trimmed by half in August if it sprawls. Clear the dead top growth of all of them in February.
Which hardy geranium is best for shade?
Geranium macrorrhizum for dry shade and Geranium phaeum for deeper, moister shade. Both flower in May and make dense ground cover under trees and shrubs where little else will. G. nodosum is another for dry shade.
What is the difference between hardy geraniums and pelargoniums?
Hardy geraniums, or cranesbills, are frost-hardy border perennials that stay in the ground all year. The red and pink 'geraniums' sold for summer pots are pelargoniums, tender plants from South Africa that must be kept frost free over winter.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.