Geranium Growing Guide
Pelargonium spp.
The garden geranium most people plant in pots isn't a true hardy geranium at all — it's a Pelargonium, and it can be overwintered indoors for years of reuse.
Light
Full sun to light afternoon shade
Soil
Well-drained, moderately fertile potting mix or garden soil
Water
Let the top inch dry between waterings
Hardiness
Grown as an annual in most of Canada (Zone 10+ perennial)
Mature size
1–2 ft, mounding or trailing depending on type
Bloom time
Late spring through frost
The 'geranium' sold in garden centre flats every spring — the classic red, pink, or white porch and window-box flower — is technically a Pelargonium, not a true hardy Geranium (a different, related genus grown mostly for foliage). Pelargoniums won't survive a Canadian winter outdoors, but they're easy to overwinter indoors and reuse year after year.
Planting
- Plant outdoors only after all frost risk has passed and soil has warmed
- Use a well-drained potting mix in containers; geraniums dislike sitting in wet soil
- Space garden-bed plantings 10–12 inches apart to allow airflow
- Choose a spot with morning sun and light afternoon shade in hotter regions, full sun elsewhere
Watering & feeding
- Water when the top inch of soil feels dry — overwatering causes yellow leaves and root rot faster than underwatering causes wilting
- Container-grown geraniums dry out faster and may need water every 2–3 days in summer heat
- Feed every 2–4 weeks with a balanced, water-soluble fertilizer through the growing season
- Ease off fertilizer in late summer to let the plant prepare for the season's end or overwintering
Deadheading & grooming
- Snap or cut off entire flower stalks at the base once blooms fade, not just individual florets
- Remove yellowing lower leaves regularly to keep airflow good and reduce fungal issues
- Pinch leggy stems back by a third in midsummer to encourage bushier growth and a fresh flush of blooms
Overwintering indoors
- Before first frost, dig up (or bring the pot in) and cut plants back by about a third
- Pot in fresh, well-drained soil and place in a bright, cool spot (55–65°F) indoors
- Water sparingly through winter — just enough to keep roots from fully drying out
- Alternatively, bare-root storage works: shake off soil, hang upside down in a cool, dark, dry place, and rehydrate roots in spring
- Resume normal watering and feeding, and move back outdoors once frost risk has passed
Common problems
- Yellow lower leaves: often overwatering or normal natural leaf drop — check soil moisture before adjusting anything else
- Leggy, sparse growth: usually insufficient light — geraniums need real sun to stay compact
- Botrytis (grey mould) on flowers in humid, crowded conditions: improve airflow and remove affected blooms promptly
- Edema (corky raised spots on leaves): caused by overwatering combined with high humidity and low light — reduce watering
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Frequently asked questions
No. The classic red/pink porch-and-planter flower is a Pelargonium and is frost-tender. True hardy Geraniums are a different (related) genus grown mainly as perennial groundcover with much smaller flowers.
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