Can Alpine Geraniums Be Divided?

Types

• While numerous species of Erodium may grown gardens across the United States, one species in particular is frequently called the alpine geranium: Erodium reichardii. This mound-forming, often evergreen perennial slowly grows only 3 inches tall and 6 to 12 inches wide. Native to Majorca and Corsica, it performs best in full sun in an organic rich, gritty but well-drained soil. It isn't overly tolerant of winter cold or excessive humidity, and is best in U.S. Department of Agriculture plant hardiness zones 7b, 8, 9 and 10a where winters never get colder than 5 to 10 degrees Fahrenheit. Several cultivars of Erodium reichardii exist, offering more leaf and flower features for gardeners to choose from.

Plant Division

• The best time to dig up and divide an alpine geranium is in spring, just before new growth begins. Plants typically are evergreen, but in unusually cold winters the plant are semideciduous. Dig and divide the root clumps in late February or March as the days lengthen and the soil and air gradually warm. Transplant immediately to prevent root drying, and plant the root ball at the same depth as it previously grew. Lightly water to eliminate air pockets in the soil, but do not overwater, which can cause root rot and plant death.

Insight

• Avoid dividing alpine geraniums in summer or fall, as the conditions are not conducive for the best re-establishment of roots. Summer heat stresses the plant, and energy is normally shifted to producing flowers rather than forming new roots. Fall division is problematic as the cooling soil, production of seed and slowing growth heading into winter all divert resources to tasks other than root growth. In hot summer regions, planting divided alpine geraniums in partial-sun to partial-shade conditions, with shade occurring from noon to late afternoon, diminishes the need for watering and potentially causing rotted roots from overly wet soil.

Other Propagation Options

• In addition to dividing clumps of alpine geranium to get more plants, you may sow seeds or take basal stem cuttings. Seeds ripen in early fall, usually September, and need to be immediately sown. Sow the seeds in containers filled with soil similar to the garden soil where the mother plant grew: gritty with fine particles of humus and an alkaline pH. Keep the soil barely moist and allow seedlings to germinate across the fall and winter months per outdoor conditions. In late spring or early summer, clip off stems in plants that grow adjacent to the soil. Layer the cut stem bases atop porous soil in containers where they will root across the warmth of summer.