Geranium macrorrhizum
Bigroot geranium
Common names: Hardy geranium, Rock geranium, Balkan cranesbill
At a glance
- Light
- Partial shade
- Pot size
- from 5 l
- Lifespan
- Perennial
- Flowering
- May–Jul
- Hardiness
- Hardy down to −30 °C
- Water need
- Low
Photo: Didier Descouens · CC BY-SA 4.0 · Source
This description was machine-translated.
Description
Bigroot geranium, botanically Geranium macrorrhizum, is a robust ground cover native to the southern Alps, the Apennines, and the Balkans. It grows where other perennials struggle, under trees and shrubs, in dry shade, and at the base of walls. It reaches 20 to 50 cm in height. Strong, creeping rhizomes produce a dense mat of hand-shaped, lobed, aromatically scented leaves that suppresses weeds. From May to July, brightly colored purplish-red to crimson flowers appear above the foliage; in cultivars such as 'Spessart', the flowers range from white to pale pink. In autumn, the leaves turn yellow to orange-red, and in mild winters some remain green. It is only distantly related to balcony geraniums and, unlike them, is fully hardy. It spreads slowly via its rhizomes and can be easily contained with a spade.
Care instructions
Plant bigroot geranium in spring or autumn in a partially shaded spot, though it also thrives in sun and deep shade. Normal, well-drained garden soil is sufficient; it does not tolerate waterlogging. Space plants about 40 cm apart and water regularly in the first year. Afterward, it copes with dry summers, even in dry shade under trees. After flowering, cut off the spent flower stalks, and in spring remove old, brown leaves. If the mat becomes too large, cut around the edges with a spade and replant the pieces elsewhere. Before planting, consider where it may spread, since it quickly becomes dominant among delicate perennials. Mulch is not needed, as its dense foliage covers the soil by itself.
The care notes were machine-translated from German.
Garden year
FloweringMay–Jul
Soil & site
Soil pH
Soil type
well-drained, humus-rich, loamy, dry
Bigroot geranium is undemanding and grows in almost any well-drained garden soil, whether humus-rich, loamy or stony, slightly acidic or chalky. It also copes with dry soils, even under trees, where the roots of the woody plants take the water. Only permanently wet, compacted soil does not suit it; there the rhizomes rot. On heavy loam, mix in sand or grit.
Feeding
Light feeder
Bigroot geranium needs no fertiliser. It is adapted to nutrient-poor, stony sites and grows dense and strong even on lean soil. Too many nutrients only make the foliage larger and softer. If the soil has very little humus, a thin layer of compost in spring is enough. In a container too, it is enough to repot it into fresh soil every few years.
Overwintering
Bigroot geranium is fully hardy and needs no protection. Some of the leaves stay green in winter, which is normal. Clear away the old, brown foliage only in spring. In a container, put the pot against a sheltered house wall in winter and make sure no water stands in the saucer, because wet harms it more than cold.
Propagation
Methods
- Division
- Cuttings
Bigroot geranium is easily propagated by division or rhizome pieces. In spring or in September, dig up a piece of the carpet and divide it into pieces with roots and shoots. You can also cut off individual rhizome pieces with at least one bud, 5 to 8 cm long, and lay them shallowly in sandy soil; they root within a few weeks. Water the young plants regularly until they have taken. Varieties such as ‘Spessart’ are propagated only in these ways.
For your garden
Grow Bigroot geranium yourself
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