Robert Geranium: A Hardy Ground Cover with a Wandering Spirit
Meet Robert geranium (Geranium robertianum), a charming little plant that’s both loved and questioned by gardeners across North America. With its delicate pink flowers and finely cut leaves, this hardy annual-to-biennial herb has quite the personality – and quite the ability to make itself at home just about anywhere.
What is Robert Geranium?
Robert geranium is a small forb – that’s gardener-speak for a non-woody herbaceous plant – that typically completes its life cycle in one to two years. Despite its common name, it’s not actually related to the showy geraniums you might know from garden centers. This little wanderer belongs to the true geranium family and has a much more subtle, woodland charm.
The plant produces small, five-petaled flowers in shades of pink to purple, usually about half an inch across. Its deeply divided, palmate leaves give it a delicate, lacy appearance, and in fall, the foliage often turns attractive shades of red and orange before the plant completes its cycle.
Where Does Robert Geranium Come From?
Here’s where things get interesting from a native gardening perspective. Robert geranium is native to Europe, western Asia, and northwestern Africa, but it has naturalized extensively across North America. In Canada, it’s considered native, but in most of the United States, it’s a non-native species that has made itself quite comfortable.
You can find Robert geranium growing wild in an impressive list of locations: Alaska, British Columbia, Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec, Newfoundland, and numerous U.S. states including California, Connecticut, Delaware, Illinois, Indiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, New Hampshire, New Jersey, New York, Ohio, Oregon, Pennsylvania, Rhode Island, Tennessee, Vermont, Virginia, Washington, West Virginia, and Wisconsin.
Should You Plant Robert Geranium?
This is where Robert geranium becomes a bit of a garden diplomat. It’s not listed as invasive or noxious, but it does have a reputation for enthusiastic self-seeding. Here are some considerations:
Reasons You Might Want to Grow It:
- Excellent ground cover for shady areas
- Attractive to small pollinators like bees and flies
- Thrives in challenging woodland conditions
- Provides seasonal interest with flowers and fall foliage color
- Very low maintenance once established
- Hardy across USDA zones 3-9
Reasons You Might Want to Think Twice:
- Can self-seed aggressively and spread beyond intended areas
- May crowd out native woodland plants
- Short-lived individual plants (though they readily replace themselves)
- Not native to most of the United States
Native Alternatives to Consider
If you’re committed to native gardening, consider these lovely alternatives that provide similar woodland charm:
- Wild ginger (Asarum canadense) for ground cover
- Native wild geraniums (Geranium maculatum)
- Foamflower (Tiarella cordifolia)
- Wild strawberry (Fragaria virginiana)
Growing Robert Geranium Successfully
If you decide to welcome Robert geranium into your garden, here’s how to keep it happy (and under control):
Ideal Growing Conditions:
- Light: Partial shade to full shade
- Soil: Moist, well-drained soil; tolerates various soil types
- Water: Moderate moisture; avoid soggy conditions
- Hardiness: Zones 3-9
Planting and Care Tips:
- Start from seed in fall or early spring
- Seeds can be direct-sown in garden beds
- Space plants about 6-12 inches apart
- Deadhead spent flowers to prevent excessive self-seeding
- Pull up unwanted seedlings while they’re young
- Mulch around plants to retain moisture and suppress weeds
Habitat and Environmental Benefits
Robert geranium has a wetland status of Facultative Upland across all regions, meaning it usually grows in non-wetland areas but can occasionally pop up in wetland edges. This adaptability is part of what makes it such a successful colonizer.
The small flowers do provide nectar for various small pollinators, including native bees and beneficial insects. However, the ecological benefits are generally considered modest compared to native alternatives.
The Bottom Line
Robert geranium is a bit like that charming houseguest who’s delightful company but tends to overstay their welcome. It’s a pretty, low-maintenance plant that can solve ground cover challenges in difficult shady spots. However, its enthusiastic self-seeding means you’ll need to stay on top of managing its spread.
For native plant purists, there are wonderful native alternatives that provide similar benefits with greater ecological value. But if you’re drawn to Robert geranium’s understated charm and don’t mind playing occasional garden referee, it can be a lovely addition to woodland gardens and naturalized areas.
Just remember: with Robert geranium, a little goes a long way, and vigilant deadheading is your friend!
