Living Mulch: Make Your Garden Almost Weed-Free with Ground Covers

Anyone who does not want to spend every weekend in spring weeding on their knees can make their garden almost weed-free with a smart planting technique.

Rather than carrying basket after basket of weeds out of their borders, more and more amateur gardeners are relying on a living carpet of perennials. Carefully chosen, closely planted ground-cover plants take on the work otherwise done with a hoe and by hand – and March is the ideal time to begin.

Why weeds keep returning despite constant weeding

A huge store of seeds lies dormant in the soil. Gardeners call this a “seed bank”. Seeds deposited over decades wait for light, moisture and air before springing into action. That is exactly where the trouble starts.

Digging deeply or leaving borders bare for long periods brings those seeds to the surface. Once they receive light, they germinate – and the weeding cycle begins again. In a sense, every intensive bout of soil cultivation reopens the seed account.

Permanently bare soil practically invites wild plants in. Every gap will be occupied – either by perennials you plant or by what you regard as weeds.

There is another factor: not every unwanted plant behaves in the same way. Annual species, such as chickweed or purslane, mainly spread through seed. Perennial plants with taproots, including dandelions or cleavers, are deeply anchored and can regrow from leftover root sections.

A different approach for different weeds

Anyone hoping to reduce their workload needs a basic idea of what they are dealing with. In practice, this simple classification is usually enough:

• Annual wild plants: germinate from seed, flower, die back and leave behind fresh seeds.
• Perennial deep-rooted plants: develop strong roots and regrow from pieces of root.
• Woody seedlings: young trees and shrubs which become difficult to remove if left too long.

Annual species are best cut off just above ground level instead of being dug around deeply. This removes the plant without bringing fresh seeds up from below.

Perennial deep-rooted weeds require another method. The soil should be damp but not waterlogged. A dandelion weeder or narrow spade can then be used to loosen taproots reasonably deeply. The fewer root fragments left in the ground, the less often the plant will return.

Small seedlings of maple, beech or ornamental shrubs can also cause problems. Ignore them and, within a few years, you may have a root problem in the border. Ideally, pull out these young plants during their first year; later on, digging is required.

Living mulch: how perennials simply crowd out weeds

The traditional answer to unwanted growth is bark mulch. It covers the soil and suppresses many seeds. However, it needs topping up regularly, uses up some nitrogen as it decomposes and does not suit the look of every garden.

“Living mulch” is a much more interesting option. This means perennial ground covers that spread across the soil like a green, flowering blanket. They shade the ground, deny seedlings the light they need and take up water and nutrients before the “unwanted” plants can get to them.

A dense carpet of perennials allows hardly any light to reach the soil – seedlings simply stand no chance.

These plants offer several benefits at once:

• They keep the soil cool and moist.
• They protect against surface capping and erosion during heavy rain.
• They provide insects with pollen, nectar and shelter.
• Over time, they save considerable effort because little hoeing is needed.

Brunnera macrophylla – the star among spring ground covers

Among professionals, Siberian bugloss (Brunnera macrophylla) is considered a real workhorse for shady and partially shaded spots. This variety forms dense clumps, spreads readily and makes a striking floral display in spring.

Typical characteristics of this perennial include:

Characteristic	Brunnera macrophylla
Position	Partial shade to shade, humus-rich soil
Flowering period	Roughly mid-March to mid-May
Flower colour	Bright blue, similar to forget-me-nots
Growth habit	Forms dense carpets and self-seeds readily
Special feature	Varieties with silver-patterned leaves are also available

Particularly in shady borders, beneath shrubs or along the edge of woody planting, this perennial turns dull soil into a bright carpet of flowers. Where you once had to hoe between individual plants, a quick check is usually enough later on to see whether a persistent intruder has pushed through.

How to plant in March, step by step

March is ideal because the soil is generally drying out but still fresh at this point. Plants then have a full growing season to establish themselves before the following winter arrives.

1. Prepare the soil
   On a frost-free day, remove all existing weeds thoroughly, roots included. Loosen only the top layer rather than digging deeply, so that no fresh seeds are activated.

2. Work in compost
   Spread a thin layer of mature compost and rake it lightly into the surface. This supplies nutrients while keeping the soil relatively undisturbed.

3. Keep planting distances close
   Ground-cover plants should deliberately be planted closer together than conventional perennials. Depending on the species, a spacing of 20–30 centimetres is appropriate. The aim is for the leaves to meet within one to two years.

4. Water thoroughly
   Water each plant well after planting. This settles the soil around the roots, removes air pockets and helps the plants establish.

5. Support the first season
   During the first year, water occasionally, especially through dry spells, and pull out any wild plants that emerge as early as possible.

March is considered the “starting signal”: plant carefully once, and the perennials will increasingly take over your weeding work.

Which perennials create lasting, dense ground cover

Brunnera macrophylla is only one example. Suitable ground-cover plants are available for different areas of the garden and work just as reliably.

Suitable species for shade and partial shade

• Siberian bugloss: Flowers early and thrives in humus-rich, slightly moist soil.
• Barrenwort (Epimedium): Produces delicate spring flowers and copes remarkably well with dryness beneath woody plants.
• Barren strawberry: Evergreen, with yellow flowers, and suitable for more challenging spaces beneath trees.

Sunny spots: flowers instead of gravel

In full sun, you need tough species able to withstand heat and drought:

• Thyme and other cushion-forming herbs: Fragrant and flowering, they attract bees and are ideal for border edges and dry-stone walls.
• Stonecrop species (Sedum): Cope well with poor soil and store water in their leaves.
• Cranesbill varieties: Create open yet fairly closed carpets and bring plenty of colour to the border.

It is important to plant several specimens of one species rather than mixing too many different plants together. A larger block of the same perennial appears calmer and covers the ground more effectively than a collection of individual specimens.

Tips for keeping the flowering carpet low-maintenance

Even living mulch does not look after itself entirely. A few simple rules will nevertheless keep the work to a minimum:

• Do not keep disturbing the soil: The less you hoe, the more settled the soil’s “seed bank” remains.
• Keep an eye on the edges: If ground-cover plants become too vigorous, simply cut them back with a spade and give away the surplus or plant it elsewhere.
• Consider light conditions: Perennials in shade often grow slightly taller and more open. In heavily shaded places, combining different species is worthwhile.
• Feed selectively rather than excessively: In most gardens, a little compost once a year is entirely sufficient.

If you are uncertain about how a species will behave, test it in a smaller area first. This quickly shows whether its growth habit, height and flowers suit your own garden style.

What terms such as “living mulch” really mean

The phrase “living mulch” ultimately describes a straightforward idea: instead of spreading organic material, such as bark pieces, over the soil, a layer of plants performs the same role – while bringing far more life and colour.

For the soil, this means less temperature fluctuation and more consistent activity from soil life; earthworms and microorganisms are more comfortable. Over the years, this has a positive effect on soil structure. Water drains away more effectively, while waterlogging and bone-dry conditions occur less often.

The risks are limited, provided you do not choose extremely invasive species. Those who plant ground covers that spread too enthusiastically, such as certain forms of ivy or ground elder, will need to intervene more later. Better choices are species that knit together but can still be controlled.

The concept is also interesting when combined with vegetable gardens. Low-growing, walkable plants can be placed between taller crops to protect the soil. Examples include low thyme varieties around the edges or clover in undisturbed corners. This creates a system in which edible plants and ground covers work together – and makes the weeding basket considerably smaller.