Ground elder (Aegopodium podagraria) is a fast-growing, invasive, perennial weed that can spread quickly to form a carpet of foliage that will crowd out less-vigorous plants in beds and borders.
What is ground elder?
Ground elder is an herbaceous, invasive, perennial weed. It spreads via rhizomes (underground stems), which can regenerate from a just a tiny fragment left in the ground.
Appearance
Early in the year, shoots with dark green leaves burst from the soil. These are followed in late spring and early summer by tall stalks that support several flat heads of white flowers. There is also a form with variegated leaves. The flowers bear a resemblance to those of the elder tree (which is completely unrelated), and this gives the weed its common name.
Ground elder rhizome and young shoot.
Ground elder in flower.
The problem
Spreading by rhizomes, ground elder can easily creep in from a neighbouring garden or nearby wasteland. It can also be unknowingly introduced with new plants if pieces of its fleshy, white rhizome are hidden within the compost of the rootball or are tucked away among the roots of the plant.
Control
As its rhizomes are close to the surface of the soil, it is possible to reduce infestations of ground elder by removing it carefully with a garden fork. However, eradicating it completely needs vigilance as the smallest portion of root left in the soil will result in a new plant growing.
Non-chemical control
Tackling large infestations of ground elder in a well-planted bed can be difficult. To get rid of it completely requires time and patience. Try the following:
- Lift cultivated plants and carefully remove and destroy any pieces of ground elder rhizome from around their roots.
- After you are sure it has all been removed, replant your garden plants in clean soil or pots.
- The ground elder can now be evicted by digging, or by covering the ground with black polythene to starve the weed of light. It may take several seasons until the ground elder is completely destroyed.
In new lawns, ground elder will usually be starved by repeated mowing, and should not persist for long.
Chemical control
Established ground elder can be controlled by spraying with a weedkiller containing glyphosate (e.g. Roundup, Tumbleweed, Knockdown Systemic and Elimin8).
- Protect cultivated plants with sheet polythene or by pegging them out of the way, and take care to avoid spray drift.
- Apply the spray in mid-summer when there is lots of leafy growth, then reapply if necessary later in summer. Spraying in the evening will be far more effective than spraying during the day as more of the chemical will be absorbed by the foliage.
- Alternatively, in early spring, the residual soil-acting weedkiller dichlobenil (e.g. Casoron G4 Weed Barrier) can be applied to the soil around some trees and shrubs, without causing them damage, to control ground elder at their bases.
Download
Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners)
Links
Applying weedkillers with a sprayer
Using weedkillers safely and effectively