In our own landscaping, mulch is usually a starting point, not the finished plan.
When we plant a new bed, we still use leaves, wood chips, bark or whatever mulch makes sense for the site. Bare soil needs protection while the plants are small, and a good layer of mulch helps hold moisture, reduce erosion and slow down the first flush of weeds.
But mulch is also something you have to keep buying, hauling and spreading.
Over time, we would rather have more of that ground occupied by plants.
That is where living mulch comes in. Instead of maintaining wide open spaces between perennials indefinitely, we use low-growing plants, spreading plants, small grasses, sedges and other dense herbaceous plants to gradually cover more of the soil.
Done well, it reduces the amount of mulch a bed needs, gives weeds less open ground to move into and makes the planting feel more established. It also gives you another layer of flowers, foliage, roots and habitat.
Living Mulch Is Really About Filling Space Efficiently
A planted ground layer does not need to be a single species, and it does not need to form a perfectly flat carpet.
Some plants really do spread across the soil.
Creeping Phlox is an obvious example. It grows low, runs outward and gradually forms a mat. Green and Gold grows similarly in part shade and moist woodland conditions, forming a low patch of foliage with yellow flowers held just above it.
Running Tapestry Foamflower is another good woodland option. It spreads by runners and can weave itself through the lower layer of a shady bed rather than sitting as one isolated clump.
Golden Ragwort is stronger still. Where it is happy, especially in moist soil and part shade, it can build a fairly substantial colony. We would use that in a place where we want it to freely occupy ground rather than trying to keep it inside a tiny pocket.
Other plants cover soil more gradually.
Self Heal stays low and can settle into spaces between taller plants. Lyreleaf Sage forms low rosettes close to the ground and then sends up flowering stems in spring. Downy Wood Mint can spread into loose colonies while still leaving a softer, more mixed look than a solid carpet.
That difference is useful because not every bed needs the same kind of groundcover.
Sometimes we want a plant that moves quickly and fills a large area. Sometimes we want smaller plants repeated through the bed so they share the ground without one species taking over.
Grasses and Sedges Can Be Part of the Ground Layer Too
A living mulch does not have to be broadleaf foliage.
We use a lot of grasses and sedges this way because their root systems hold soil well and their narrow foliage can fill space without making a bed feel heavy.
Buffalo Grass is especially useful in sunny, drier ground because it actually spreads and can form a low cover. It is much more ground-hugging than the taller native grasses people usually picture.
June Grass stays relatively small and grows in tidy clumps. It is not going to run across a bed, but planted repeatedly it creates a low grassy matrix between flowering perennials.
Nash’s Blue-Eyed Grass gives a similar fine texture, although it is actually in the iris family rather than being a true grass. Its foliage stays low and narrow, and the blue spring flowers are a nice bonus.
For slightly taller texture, Sideoats Grama can fill the lower and middle layer in a sunny planting without becoming a huge grass. Nodding Fescue works especially well where there is more shade, and Cherokee Sedge is useful in woodland edges and partly shaded beds where many traditional lawn grasses struggle.
Tufted Hair Grass is worth considering in moister sites. It forms a dense clump, handles wetter soil better than many grasses and can help bridge the space between low groundcovers and taller flowering plants.
A dense planting can be built with clumps, rosettes, runners and spreading colonies all mixed together to create a visually interesting low-growing ground cover.
Sunny Beds And Dry Spaces
Dry, sunny beds are often where we end up using the most mulch simply because the soil between young perennials is so exposed.
There are a lot of plants that can help fill that ground over time.
Yarrow is useful because its basal foliage spreads close to the soil before the flower stems rise above it. Pink Evening Primrose can travel considerably farther and is better where there is room for it to make a colony rather than in a tightly controlled formal border.
Snow Flurry Aster is one of my favorite plants for this purpose because it behaves very differently than the taller asters we usually feature. It stays low, spreads outward and becomes covered in small white flowers late in the season.
Wild Petunia stays relatively low, handles dry ground well and can fill sunny openings without becoming a heavy mat.
Nodding Onion is another good example of a plant that does not look like a conventional groundcover but still belongs in the lower layer. Its foliage is narrow, its flowers sit above the bed rather than dominating it, and repeated plants can occupy sunny spaces nicely. Plus alliums are a wonderful natural pest deterrent.
A ground layer of yarrow, Snow Flurry Aster, June Grass and Lyre-Leaf Sage can support taller plants such as Bush’s Coneflower, Pale Purple Coneflower, Aromatic Aster, Bradbury’s Bee Balm or Shining Blue Star without leaving several feet of bare mulch around every crown.
The lower plants cover the soil. The taller plants provide the height, flower display and structure.
Shadier Plantings for Shadier Spots
Woodland edges and partly shaded beds are some of our favorite places to use living mulch because there are so many good plants for the lower layer.
Green and Gold, Running Tapestry Foamflower, Wild Blue Phlox, Downy Wood Mint and Golden Ragwort can all be used in this kind of planting, although they differ quite a bit in how aggressively they move.
Green and Gold is relatively low and spreading. Running Tapestry Foamflower sends out runners and gradually threads through the bed. Wild Blue Phlox forms looser colonies and gives the lower layer more height in spring.
Downy Wood Mint has a soft, woodland character and works well around other natives rather than looking like a conventional landscape groundcover.
Golden Ragwort is the one we would give the most room. In the right conditions, it can become a broad colony, which is useful if you are trying to cover a larger bank, woodland edge or moist area.
You can mix those with smaller clumping plants such as Cherokee Sedge, Nodding Fescue or compact Heucheras rather than relying on one species to do everything.
The result is still a groundcover planting, but it has several kinds of foliage, different bloom times and different root habits working together.
Living Mulch Still Needs Mulch While It Gets Established
Although we are establishing a living mulch, the soil still needs protecting until the foliage has had time to grow in.
Small plants installed this fall are not going to cover a bed overnight. For the first season, we still mulch around them and keep an eye on weeds while roots establish and plants begin spreading.
As the planting fills, the amount of visible mulch gradually gets smaller.
That is a very different approach than applying several inches of bark every year forever.
We can still refresh mulch where it is needed, especially around young shrubs, trees or newly divided plants, but we do not need to maintain the same wide open mulched spaces indefinitely.
Many Groundcovers Are Easy to Expand Yourself
This is another reason we like using perennial groundcovers.
Once a planting is established, many of these plants are very easy to divide.
Creeping Phlox can often be lifted in rooted sections. Green and Gold can be divided as patches expand. Self Heal, Lyreleaf Sage, Golden Ragwort and Downy Wood Mint can all give you material to move into another part of the garden once colonies become large enough.
Clumping plants are straightforward too. Sedges, small grasses and many woodland perennials can be dug and divided into smaller sections once they have developed a healthy root system.
We would not divide a new plant immediately after planting it. Give it time to establish first, but after a few seasons, one patch can become several.
That matters in a larger landscape. You do not always have to buy enough plants to cover every square foot on day one. Start with good spacing, let the plants grow, then use divisions to continue filling the bed.
It is slower than laying a pallet of mulch, but it becomes more useful over time rather than needing to be replaced.
Some Plants Should Be Allowed to Spread. Others Should Be Kept in Check.
Living mulch works best when you know how the plant grows before putting it in the ground.
Pink Evening Primrose, Golden Ragwort, and Yarrow can widen and seed around. Buffalo Grass will spread where conditions suit it.
That is not a flaw if the site needs coverage.
It can become a problem if you put an enthusiastic spreader next to a small, slow-growing plant and expect both to hold exactly the same amount of space for the next ten years.
We like to give the stronger plants room to do what they naturally do, then use slower plants where we want a quieter edge.
The same goes for trees and shrubs. We still leave a clear mulched area around young woody plants rather than packing groundcover right against the trunk. Newly planted trees need access to water and root space without heavy competition immediately around them.
Once a woody planting is established, the lower layer can move closer, but it should never pile against the bark or bury the crown.
Fall Is a Good Time to Start
The plants may not look especially dramatic when they go into the ground in October.
Some are already slowing down. Warm-season grasses are changing color, spring bloomers are mostly foliage, and many herbaceous perennials will disappear completely after frost, but that is fine.
The soil is still warm, the air is cooler and the plants can begin establishing roots without dealing with summer heat. By spring, they are already in place and ready to start filling the spaces between the larger plants.
We have particularly good numbers right now of Buffalo Grass, Nash’s Blue-Eyed Grass, Creeping Phlox, June Grass, Cherokee Sedge, Nodding Fescue, Tufted Hair Grass, Green and Gold, Lyreleaf Sage, Self Heal, Pink Evening Primrose, Snow Flurry Aster, Wild Blue Phlox, Running Tapestry Foamflower, Golden Ragwort, Downy Wood Mint, Sideoats Grama and Yarrow.
Those plants do not all grow the same way, and we would not use them in the same site.
That is part of what makes living mulch useful.
Dry sun, moist shade, woodland edge and open perennial bed can all have a planted ground layer, but the plants doing the work should match the conditions.
For us, the goal is not to eliminate mulch completely.
We use mulch where it makes sense, especially while a planting is young. We just do not assume bare mulch has to remain the permanent space between every plant.
Give that ground to roots, leaves and flowers where you can. Over time, the garden will do more of the covering for you.
