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10 Plants That Will Thrive in Shallow Soil (& 6 Tips for Planting a Shallow Garden)

I have a confession to make. I’ve been procrastinating on working on my very small front garden for the past three summers. 

Here is what my shallow garden looks like. 

A simple sidewalk garden that could do with a bit more life.

That’s strange for me because, when it comes to gardening, procrastination is not my default mode. Quite the opposite, in fact, as evidenced by my portfolio of garden projects on this website alone (plus the many projects I don’t document as thoroughly). 

Yet I’ve been putting off adding more green to this patch because I have no idea what plants will do well in a shallow garden. And unlike other gardening predicaments, when there’s usually too much information to sift through, this time I didn’t find enough information about plants with shallow roots. 

Not too bad, right? It is, actually. What it looks like is quite deceptive. 

When we first moved into this house, I had big dreams of a beautiful pollinator garden in this patch. It looked nice and healthy and there was already a climbing hydrangea growing there, so the soil had to be good, right? 

As it turns out, there is no soil there. 

Digging didn’t lead anywhere. There was no topsoil here, just mulch.

I removed some of the mulch only to discover that underneath it was more mulch, then a very thin layer of soil (a couple of inches at most), which I can only assume is just mulch that has decomposed over time. 

Digging a bit deeper, I found a very thick plastic weed-suppressing tarp. I hate them with a passion, but at least this one seemed not to be falling apart for now. 

There it is, the dreaded weed suppressant! Underneath it, there was sand all the way down.

Ok, I can remove that, I thought to myself. Let’s see what’s suppressing underneath. SAND! Lots and lots of sand! So the tarp seems to be holding the sand together more than suppressing any weeds. I honestly don’t know how deep the sand goes, but after probing the depth with a bamboo cane, it seems that there’s sand all the way down. 

So why not dig it all out and make the garden deeper?

First, a bit of a back story. 

During our first spring in this house, we built raised beds, sunk beds, container gardens and flower boxes in the backyard; most of this backbreaking work required removing pavers, digging out sand, bagging it and disposing of it at the local reclamation center at the landfill. 

We then filled up the beds with bags and bags of compost and topsoil because no bulk supplier would deliver to our zipcode. We’ve now reached a point where we’re making most of our own compost, building up the soil and improving it gradually in collaboration with wildlife. 

Digging up all the sand underneath was not worth the effort.

The thought of removing and disposing of even more sand sends chills up and down my spine. Not to mention my husband’s spine, since he’s the one doing most of the heavy lifting, quite literally. 

So we’ve decided to work with what’s there. As a sort of compromise, we scraped back some of the mulch, added a bag of good garden soil, then planted our shallow-rooted plants and covered everything with mulch again. We’ve created a few gentle slopes just to promote better drainage and a mild cascading effect once the creeping plants start growing.    

This is as much as we could fit. More info on the plants included in the list below.

Why would you plant a shallow garden?

My peculiar gardening setup is not the only scenario in which planting a shallow garden makes sense. A shallow garden might be your only choice if you’re planting above a septic tank or trying to cover up a septic drain field. 

Similarly, it’s a good gardening approach if you want to plant something on top of pipelines running across your property. Plants with a strong and deep root system might cause problems to the integrity of your pipes over time.

You can grow shallow gardens on rocks or piles of debris.

In my research, I even came across shallow gardens planted on piles of construction debris. The waste was left on site and turned into a beautiful garden. In some cases, that’s a much better use of it than having it linger in a landfill forever. 

The challenge of finding plants for shallow gardens.

The main challenge, for me, was finding what plants are truly suitable for shallow gardens with poor soil. And I say this as someone who knows a thing or two about plants. Someone who reads books and takes courses and gardens and writes about plants. I had no idea where to start and all the information I found seemed unsatisfactory at best, if not downright wrong.  

Campanula is a creeper that can grow well in shallow soil.

So you see, the procrastination I mentioned before was actually a period of intense field observation. I visited botanical gardens and took notes on what plants were growing in their rock gardens. I paid attention to what plants I found growing around the sidewalk trees in my neighborhood. And I strolled around as many open community gardens as I could find (it turns out that’s a lot when you’re traveling). 

All in all, I did my homework. About three summers’ worth of homework before I bought any plant.  

Here are some tips for planting a shallow garden so that you don’t have to procrastinate for years, like I did. 

6 Tips to Plant a Thriving Shallow Garden 

Tip 1: Get familiar with different types of root structures.

Whether we buy our plants online or from garden centers, they always come with a label that details the type of plants we’re buying (annual or perennial), their ideal growing conditions (full sun, part shade, etc.) and their water requirements. In some cases, you might even get flowering or pruning information. 

Perennials such as moss phlox have a shallow root structure.

But one of my pet peeves is that information about what kind of root the plant has is completely lacking. I won’t get into details about all types of root structures for annual and perennial ornamentals. But when you’re planning a shallow garden, there’s one to look for and another one to definitely avoid. 

Look for plants that have a shallow (often fibrous) root structure, such as thyme, sedums and most of the plants on the list that follows. This type of root stays close to the surface and usually spreads horizontally.

Perennials such as sea holly (Eryngium) send tap roots, not at all suitable for a shallow garden.

Avoid plants that have a tap root system, such as eryngium, valerian and baptisia. This type of root grows straight down into the ground and it has adapted to serve two purposes: to anchor the plant and to reach water. 

Tip 2: Some bulbs and tubers will work, but not all of them. 

Ok, but how about other types of root systems, such as bulbs and tubers? This, of course, depends on how shallow a garden we’re talking about, the type of bulb, and the climate conditions you’re gardening in. 

You could get away with planting some smaller bulbs, such as snowdrops, crocuses, mini irises (Iris reticulata) and species tulips (the smallest ones). However, larger bulbs such as most tulips and hyacinths need to be buried at about three times their width. This kind of depth is usually a luxury you don’t have in a shallow garden.

Species tulips are the smallest ones, the closest relations to their wild counterparts.

Generally, if you can start and grow this type of bulb in a shallow pan, such as you’d customarily do with dwarf irises, it’s probably safe to plant them in your shallow garden too. As long as you keep in mind that you should be able to bury the bulb deep enough to protect it from a deep freeze.

Tip 3: Look for the creepers.

There are some plants that have a creeping growth habit. That means they spread by sending lateral shoots that, in turn, send their own roots into the ground in the new location. For some of them, such as creeping phlox and creeping Jenny, this growth pattern is revealed in their popular name. For others, such as savory (Satureja), it’s a little bit less obvious. Generally (but not always), these plants will have a shallow root system suitable for shallow gardens. 

Savory (Satureja) will send new growth creeping along the soil and forming very shallow roots.

An added advantage of using creeping plants is that you don’t need too many of them to get started. Planting them a fair distance apart, then allowing them to spread horizontally along the surface of the soil, makes for an affordable option for filling up larger gardens. It might take a year or two for these plants to fill up the gaps, but the savings are worth the wait. 

Tip 4: Shallow doesn’t have to be short. 

On the other hand, not all shallow-rooted plants are of the short, creeping variety. Keep in mind that what’s above soil level won’t necessarily mirror what’s below it. So there are some mid-sized plants that can have shallow roots, such as lavender and tall sedums.  

You can grow lavender in a shallow garden, as long as the soil drains very well.

At the same time, the word “shallow” is not a universal yardstick. There are degrees of shallowness, so what works for a seven-inch deep garden (17 cm) won’t work for a three-inch deep one (7.5 cm). Experiment with both tall and groundcover plants and see what works for your site. 

Tip 5: Choose drought-tolerant plants. 

Since there isn’t much soil, there won’t be much in place to retain water. This could turn into a major challenge for shallow gardens because if you forget to water during a dry period, it might spell trouble. Let’s just say there isn’t much wiggle room for plant neglect in a shallow garden. 

One solution to this conundrum is to choose drought-tolerant plants. They still need regular watering, but you won’t lose them through periods of drought. 

Shallow gardens often need extra watering, so choose drought-tolerant plants.

There is a catch, however! Some plants have adapted to dry conditions by developing strong taproot systems. Which brings us back to our previous point of avoiding plants with deep taproots. 

So the fact that a plant can handle drought is a necessary factor, but not a sufficient factor, to turn it into the perfect shallow garden mainstay. 

Tip 6: Mulch, baby, mulch!

Whether you live in an area prone to drought or you don’t, mulching a shallow garden just makes sense. Mulching will keep your soil cool and will lock the moisture in. It also adds extra depth when depth is at a premium.  And over time, as the mulch breaks down, it will also improve the quality of poor soil. 

We finished off by restoring the mulch on top of the plants. And now, we wait for everyone to start sprawling.

Tree bark, wood chips and pine needles are three good options for mulching a shallow garden. If you’re looking for a free, DIY option, making your own leaf mold in the fall is just as effective. 

And if you’ve taken my advice and planted some creepers in your garden, even better. Over time, they’ll develop as a living mulch ground cover. 

10 Plants that will do well in a shallow garden

Now that we’ve got some basic principles covered let’s see some plants that are suitable for a shallow garden setup. 

1. Creeping phlox (Phlox subulata)

There are two types of phlox commonly used in gardening: garden phlox or tall phlox (Phlox paniculata) and creeping phlox or moss phlox (Phlox subulata). It’s the latter that I recommend for a shallow garden. In fact, you’ll often see it growing in rock gardens, on retaining walls and as erosion control on slopes. 

Moss phlox is a herbaceous perennial that will spread like a mat around two to three feet wide around the root structure, but will stay around six inches tall. The leaves of this rapidly growing ground cover are dark green, tiny and needle-like, so not much to write home about. It’s the flowers that make for a stunning display starting in mid-spring and continuing until late summer (depending on the planting location).

I’m very excited for the candy-striped flowers to start blooming.

I’m planting a cultivar called ‘Candy stripes’ – that’s exactly what the tiny tubular clusters of flowers look like in full bloom. You can also find moss phlox that blooms in shades of red, pink, purple, cream and white, all of which will create a beautiful carpet in shallow gardens.  

2. Moss rose (Portulaca grandiflora)

The name of this one is rather confusing because it’s neither moss nor a rose. You may be more familiar with its less showy cousin, the common purslane with which it shares a family (Portulacea). 

However, as the name suggests, grandiflora will have beautiful showy flowers all through the summer. The tiny rose-like blooms come in different bright colors, such as yellow, orange, pink and deep red.

Garden centers will often sell mixed-color moss rose.

But the garden centers that I usually buy from don’t even bother with selling single colors. I can only find portulaca mixes, in which several plants of different colors are growing in the same pot. That works perfectly for me, since I don’t have to pick favorites. And if you plan on starting it from seed, you’ll find the seeds mixed the same way. 

Since it’s a succulent, Portulaca grandiflora will mostly grow as an annual and die back once the frost hits. But I’ve seen it reemerge from the ground in spring when the soil didn’t freeze very deep. Just in case, I plan on taking cuttings in the fall and overwintering some moss rose indoors. Even as an annual, it spreads quickly and sends out rich blooms that attract pollinators. 

3. Hardy ice plant (Delosperma)

When I said I got my inspiration for a shallow garden just by walking in my neighborhood, this is what I mean. I’ve been seeing this hardy ice plant packed on top of the protruding roots of a very large tree growing along the sidewalk. The roots were knobbly and sticking out quite a lot, so I’m pretty sure there was less than an inch of very poor soil for the ice plant to anchor in. 

The hardy ice plant comes in all sorts of neon colors.

The hardy ice plant started blooming here and there in very early spring. By July, it was impossible to see the foliage underneath the flowers. Did I mention that nobody but the rain was watering it?

As luck would have it, I found some ice plants for sale at the monthly flower market back in June. Unlike the Portulaca, the different colors were planted separately, so I had to choose. I went for deep orange because I thought it would mix nicely with the bright pinks and yellows of the moss rose next to it. But just like Portulaca, this succulent is fast-spreading and fairly resistant to both cold and drought. 

It can handle low temperatures in the winter, but isn’t a big fan of too much moisture. Plan to take cutting to overwinter indoors, just in case. 

4. Sea pinks (Armeria maritima)

How cute is this Armeria? It goes by so many names – sea cushion, lady’s pincushion, sea thrifts, pink thrifts. I got it from a little free plant library in my neighborhood and kept it growing in a pot on my patio table. It was the first time I was growing it, so I needed to do a bit more research before incorporating it into my shallow garden. 

It turns out that I shouldn’t have worried about it because its natural habitat is coastal cliffs and crevices, growing in really shallow ground. Sea thrift is native to Northern Europe and the United Kingdom, but it’s also native to California.

The sea pinks that ended up in my shallow garden spent the better part of the summer as a potted plant.

Unlike the other plants on the list so far, Armeria stays compact and evergreen (even through harsher winters). But even though it’s fairly hardy, too much moisture will kill it. It grows slowly in a mound-like shape with globe-like flowers hovering above the foliage starting in mid-spring. 

Since we have very wet falls and winters around here, I’ve taken the precaution of collecting the seeds as a backup in case the plant dies back due to too much moisture. 

5. Coral bells (Heuchera)

So far, the plants I’ve included on this list have been of the showy flower, not so showy leaves variety. But if it’s stunning foliage you’re after, you’ll have to bring some coral bells into your shallow garden. 

In spite of its exuberant waves of foliage, and tiny foamy flowers that grow way above leaf level, heuchera has unexpectedly shallow roots. In fact, most of the time you’ll find that the root ball has the tendency to protrude a bit above ground level as the soil freezes in colder climates (this is called heaving). If you catch it early, you can gently push it down into the ground with your foot. If you notice it later, you might need to re-dig the hole and replant it.

If you want show-stopping foliage, always go for coral bells.

Depending on what climate you’re gardening in, coral bells will grow as an evergreen or a semi-evergreen. 

But can you still call it an evergreen if the leaves come in shades of purple, black or silver? The darker leaves will tolerate sun better than the lighter or greener varieties. The foliage can get scorched in prolonged sun and heat, so giving it a couple of hours of shade in the middle of the day will help this short-lived perennial last for up to five years in your shallow garden.

6. Creeping baby’s breath (Gypsophila repens)

When you hear “baby’s breath,” you’re probably thinking about the beautiful and very popular wedding bouquet filler. But the baby’s breath used by florists (Gypsophila paniculata) is not what we’re talking about here. The creeping variety (Gypsophila repens) works much better as a shallow garden plant than its much taller counterpart. They do look very much alike: a multitude of aethereal wispy blooms in shades of white, pink or purple. 

Creeping baby’s breath is the mat-forming version of the popular wedding bouquet filler.

This herbaceous perennial only grows about eight inches tall (around 20 cm), but it makes up for it by quickly speaking into a mat about 20 inches (50 cm) wide in diameter, all covered in a cloud of star-shaped flowers. You can start with one single clump which you can divide and replant in spring or late fall. Once you get it established, creeping baby’s breath will handle drought and heat very well. 

7. Thyme (Thymus)

It was only a matter of time before I suggested a plant that did double duty. But if you can include a perennial that bridges the gap between your shallow garden and a kitchen garden, then thyme would have to be it. And if you count the fact that it will bring a bevy of bees to the garden, that’s triple duty.

There are a lot of varieties of thyme to choose from. For a shallow garden, I would recommend a creeping variety that forms a thicker mat and travels faster than its taller cousins. (You’re beginning to see a creeping theme here, right?) 

Creeping thyme will bloom in a carpet of flowers, much beloved by pollinators.

Creeping thyme will do really well in full sun, but it will also tolerate part shade, as well as drought conditions. Depending on your climate, it may behave as an evergreen. In my temperate climate, it does lose its leaves when it gets cold and dark in the winter. I just trim it a bit to keep it tidy and it starts greening up again in spring. 

8. Saxifrage (Saxifraga

I admit it’s a bit of a cop-out to call this just saxifraga. This covers the whole Saxifraga genus which contains over four hundred species. But the good news is that most of the ones you’ll find in garden centers will be perfect plants for shallow gardens. And the even better news is that there are high chances of finding one that’s native to your area. 

See if you can find a saxifrage native to your region.

Saxifraga are a very popular choice for rock gardens (another theme) and their name translates from Latin as “stone breaker.” In English, you may also find it as saxifrage or rockfoil. The saxifraga you’ll find for sale usually is part of the Arendsii hybrid series, with evergreen foliage year round.

Saxifrage likes to grow in part-shade in well drained soil and, just like Armeria, does not tolerate periods of prolonged moisture. The mat – covered in white, red or pink flowers from late April until late June – will often spread to twelve inches wide (30 cm). 

9. Rhizomatous geraniums (Geranium macrorrhizum)

Ah, geranium! Finally a plant that even the most novice of gardeners has heard of. There are hundreds of types of geraniums available for cultivation, all with different growth patterns. But the only ones suitable for a shallow garden will be the ones that grow from rhizomes. You wouldn’t think that if you had a quick look at the thick, sturdy rhizomes. However, once you observe how the rhizomes spread, it makes sense. Rather than going deep underground, they kind of hover halfway above ground level holding the stems upright.  

No garden is complete without geraniums.

Rhizomatous geraniums, sometimes called rock crane’s-bill or bigroots, form a ground cover that naturalizes quickly without becoming invasive. 

The leaves will release a pleasant aroma when you brush past them. The flowers, usually pink, fuchsia, white or peach cream, grow more abundantly when the plant is placed in full sun. You can propagate this kind of geranium by dividing the rhizomes where they naturally form an angle. 

10. Upright stonecrop (Sedum)

Finally, I wanted to get back to the point that planting a shallow garden doesn’t necessarily mean planting a low garden that’s only populated by groundcovers. You can add some height to your shallow garden by choosing taller varieties of plants that have a shallow root structure. 

Of course, this will depend on how shallow your shallow garden is. Are we talking two inches or six inches? There’s a difference. And while I wouldn’t add too much height in my very windy climate, I wouldn’t shy away from it in a calmer scenario. Planting a tall stonecrop, such as Sedum ‘Autumn Joy’ is a good compromise. It still has the shallower roots of a succulent, but it adds a sculptural height to the garden. 

If you plant tall stonecrops, you won’t need to sacrifice height in a shallow garden.

This reliable perennial forms rich clusters of flowers on top of juicy, succulent foliage. As the name suggests, it opens up fully in the fall. My one piece of advice for this low-maintenance perennial is to plant it in a spot that gets as much sun as possible (preferably around six hours at the height of summer). If it doesn’t get sun, it will stretch and grow skinny and etiolated. 

As with most gardening projects, creating the perfect shallow garden takes time. And I don’t mean time to plant it. I’m referring to the time it needs to start growing and come into its own. But once it takes shape, it will look just as beautiful and satisfying as any flower garden could.