Johnson's Blue Cranesbill
Johnson's Blue Cranesbill
Clouds of True-Blue Flowers for the Early-Summer Border
Johnson's Blue Cranesbill (Geranium 'Johnson's Blue') is a long-loved classic prized for its rare, clear lavender-blue flowers that float in airy clouds above mounds of deeply cut foliage in early summer. Easygoing and reliably hardy, it weaves through the border, softens path edges, and pairs beautifully with roses and peonies. Deer-resistant and adaptable, it's a dependable performer for sunny beds in Edina, Plymouth, and Bloomington.
Johnson's Blue Cranesbill Plant Details
| Attribute | Detail |
|---|---|
| Botanical Name | Geranium 'Johnson's Blue' |
| Mature Size | 12–18 in. tall, 18–24 in. wide |
| Hardiness Zone | 4–8 (Twin Cities is zone 4b–5a — fully hardy) |
| Light | Full sun to part shade |
| Bloom Time | Early to midsummer |
| Flower Color | Lavender-blue with fine veining |
| Soil | Adaptable — tolerates Minnesota clay-loam and average drainage |
| Winter Hardiness | Reliable to about -25°F once established |
| Deer Resistance | Rarely browsed by deer or rabbits |
Landscape Uses
Border weaver: Its sprawling habit fills gaps between roses, peonies, and shrubs, knitting the border together. Space 18–24 inches apart.
Pollinator and deer-resistant gardens: Bees flock to the blue flowers, while deer leave it alone. A light shear after the first flush keeps the foliage fresh and may bring scattered rebloom.
Best Time to Plant in Minnesota
Plant in spring (late April–May) or early fall (late August–mid September). Water through the first season to establish.
How to Plant Johnson's Blue Cranesbill
Dig a hole twice the pot's width at the same depth, loosening clay and mixing in compost. Set the crown level, backfill, water well, and mulch 2 inches deep. Space 18–24 inches apart.
Watering Johnson's Blue Cranesbill
First year: Water every 2–3 days at first, then weekly. Stop 2–3 weeks before the ground freezes.
After year one: Drought-tolerant once established — water during extended dry spells only.
Q: Will it survive a Minnesota winter?
Yes — hardy to zone 4 and dependable through Twin Cities winters with no protection.
Q: Why do the flowers stop midsummer?
Its main flush is early summer. Shear the plant back by a third afterward to refresh the foliage and encourage some rebloom.
Q: Is it deer-resistant?
Yes — reliably ignored by deer and rabbits.
Q: Does it tolerate clay?
Yes, as long as the spot isn't constantly wet.
You May Also Like
Rozanne Cranesbill (Geranium): Longer-blooming violet-blue flowers for all-season color.
Catmint (Nepeta): A blue-flowered, deer-resistant partner with a similar airy habit.
Peony (Paeonia): A classic border companion that Johnson's Blue weaves beautifully around.