Ground elder

Ground elder is a pernicious, fast spreading, perennial weed, which can soon colonise and take over large areas of the garden.

Although new plants can be produced from seed, it mainly spreads through its white/creamy-white, creeping, perennial “roots” – actually underground stems or rhizomes. These grow horizontally in the soil and can spread over great distances.

Ground elder creates large clumps or carpets of foliage that can smother and kill smaller plants below. The roots can grow in between the roots of cultivated plants, making them difficult to remove and control.

• Beds
• Borders
• Lawns
• Gravel paths
• Between paving slabs
• Waste or uncultivated ground

Shoots begin to appear through the soil in late winter/early spring, producing lobed leaves that are initially apple-green, but turn darker as they age. In late spring and early summer, these are followed by tall stems producing flat heads of white or creamy-white flowers. The flowers resemble those of the elder tree, giving the weed its common name.

It dies down to its roots in late autumn and winter, lulling you into believing it has gone away! But it will grow back with a vengeance the following year.

As with most perennial weeds, never allow it to become established. This will make it more difficult to fully control. Early identification and eradication is very important.

Start by digging out as much of the ground elder as possible, including the white, creeping roots. Be rigorous as even a tiny piece left in the ground can re-grow into a new plant. A fork and hand fork are usually better tools than a spade and trowel, which will cut the roots into smaller pieces.

Once you have removed most of the ground elder, covering the soil with weed-control membrane (landscape fabric) or even thick black polythene will exclude light and may starve the roots, so they die. This can take several years until the ground elder is completely exhausted and eradicated.

If the roots are growing among established plants, you may have to lift these when dormant, from autumn to the end of winter, and tease out all the ground elder roots. Then replant in clean soil or pot them up for planting out later.

In lawns, regular mowing throughout the year and the use of lawn weedkillers should weaken it and eventually kill it.

You may unknowingly introduce ground elder into your garden when buying topsoil or manure, or in the rootballs of new plants. So be vigilant when buying these.

Contact weedkillers will burn and kill the foliage, but will have no effect on the roots, which will continue to grow, produce new leafy growth and spread further.

For best results, spray with a weedkiller based on glyphosate. This is a systemic weedkiller, which is absorbed by the leaves, then moves down to the roots to kill them.

To ensure the weedkiller works effectively:

• Spray the leaves when the ground elder is growing actively; this is mainly from March/April to September/October.
• The larger the leaf area present, the greater the amount of weedkiller that can be absorbed and move down to the roots. So don’t bother spraying when the growth first emerges through the soil – wait until the leaves unfurl and enlarge.
• Use a fine spray to thoroughly coat the leaves in small droplets.
• During the summer, spray in the evening to prevent the spray evaporating and to give maximum time for the spray to be absorbed. In spring or if overnight dew is forecast, spray earlier in the day to allow the spray to dry before dew falls.
• One application of weedkiller is unlikely to kill all the ground elder. You may need to spray once, allow the ground elder to die down, and then spray any regrowth again. Three or more applications a year, over a couple of years, may be needed to completely kill it, depending on how extensive the root system is.

Most contact weedkillers and glyphosate are total weedkillers – that is they will damage or kill any plants whose leaves they are sprayed on. Make sure you keep the spray off wanted plants – including lawns – and, if necessary protect plants by covering with polythene or similar when spraying.

Roundup Gel, which is smeared onto, and sticks to, the weed leaves, may be a better option when trying to treat ground elder growing through or close to wanted plants.

Use weedkillers safely. Always read the label and product information before use.

As ground elder spreads by its underground roots, it may be coming into your garden from a neighbouring garden or surrounding waste ground. Unless you can stop this source, it will just keep coming back.

If it’s coming from a neighbour, have a quiet word and try and encourage them to control the ground elder in their garden.

If it is coming through from a relatively small area, it is possible to put a vertical physical barrier in the soil on your boundary to prevent it coming in. Suitable root control barriers and membranes are available from builders’ merchants.

• Spade
• Fork
• Hand fork
• Weed-control membrane
• Glyphosate-based weedkillers
• Roundup Gel
• Lawn weedkillers