Microminiature groundcovers

Small, low-growing groundcovers for your railway
3. One winter, Jerry and Alison Ogden thought their Irish moss had gone away but it’s coming back to the Possum Creek Railroad.
Nancy Norris
4. The Ogdens help the green carpet to creep away from the track. Note the boundary of mini boulders.
Nancy Norris
5. “If you take any longer to make that putt, this scotch moss will grow around us… and that bee at your left will think we’re flowers!”
Nancy Norris
6. Crowberry, an evergreen mat of the tiniest leaves, produces black fruit. A modeling idea: plant it next to a bowling alley with the sign: “Pick your own bowling balls.”
Nancy Norris
7. Robin and Lucia Edmond bought natural tufa rocks and sunk them in the ground so that moisture wicks up to the native moss and a little mound of Saxifraga x ‘Haagii’.
Nancy Norris
1. It seems this Elfin thyme has been groomed into a seamless, flat meadow. Not really—it just has the correct, sunny, well-drained conditions in Richard and Melinda Murray’s Green Hills Railroad.
Nancy Norris
2. Modeling a mining village in Colorado, Paul and Rene Jacobs grow Korean velvetgrass and Corsican mint to keep other larger weeds out of town on their Saratoga Branch of the Colorado & Southern Railroad.
Nancy Norris
Locating moderately spreading groundcovers to serve as micro lawns, fields, and meadows can be harrowing. The grass can seem greener over the fence because, within each hardiness zone and within each garden, microclimates make some plants thrive and others struggle. If you wait a season or two, the thriving ones may undergo periodic problems while the slackers suddenly run rampant. That’s a garden!

For example, our local hero, Elfin thyme (photo 1), filled in the farm from fence to fence in just one year. Then the tree overhead grew. In too much shade, Elfin and other thymes stretch in search of light and form bumpy hummocks. Depending on where the thyme is growing, a hilly effect can look fine. However, some gardeners prefer the small-leafed herb to grow flat so that farm fields, orchards, or lawns look realistic.

To achieve a horizontal appearance, plant thymes (and other sun lovers in chart 1) so they receive five or more hours of sun a day. Don’t over-feed or over-water your groundcovers, which would prevent slow, steady growth. Thymes and many alpine plants originating from mountainous climes thrive in gritty, poor, well-drained soil.

Prepare a platform

Why are we so fussy about low groundcovers? Primarily because the ground is the stage from which every other object in our miniature garden is measured. That floor is needed to balance the verticality of trees and structures—literally, to ground the scene. It keeps our interest cohesively glued from object to object. After spending considerable time clipping branches from the bottoms of little trees, it’s nice if the groundcover doesn’t obscure the tree’s tapered trunk.

“How can I keep my mini lawn and pasture low?” is the number-one question concerning miniature gardens. It’s been a puzzle for full-scale (1:1) landscaping, too. If you were to discover a groundcover that stayed small, with no mowing or maintenance, you’d be rich! The turfgrass industry has been trying for decades. Forty years ago, 4"-high zoysia, or Korean velvetgrass, seemed like a no-mow panacea until much of the state of New Jersey found that a harsh winter killed their exotic lawns. Even in warmer zones, zoysia inexplicably dies or goes dormant in patches but, if you can grow it, you won’t have to mow it.

Next to the town’s buildings in photo 2, the groundcovers are near unnoticeable. Effectively, they allow the stores to tell their tale of an era gone by. On closer inspection, the taller grass, zoysia, perfectly incorporated among the ledge rocks, suggests the area never was manicured and we wonder about the owner of that business. In contrast, across the street, in front of the Mineral Belt Supply and the Dry Goods store, the 1⁄4"-high Corsican mint looks like it’s been stepped on recently, so there is life just behind those doors! What we don’t see is the landscaper/owner of the garden railway, who has to keep those low spreaders in check with periodic scraping of the zoysia out of the gravel road and pouring boiling hot water on the Corsican mint to prevent it from overcoming the track roadbed (see “Plant portrait” this issue).

All groundcovers have issues. The caretaker of the Irish-moss field in photo 3 was about to give up on this season’s patchy growth when the low, grassy groundcover began to fill in again, looking every bit the part of a country meadow in the wooded clearing. The same railway gardener had the opposite situation in photo 4, and lined his track with pebbles to ward off the creeper, named green carpet (Herniaria sp.).

Make do or do without

Even the best, lowest, slowest groundcovers gotta grow! Here are more ideas for coping but first, a secret: those perfect, seemingly flat groundcovers may be hiding the fact that they are uniformly matting several inches from the ground. We see only the top. To keep figures from toppling or drowning, it’s a good idea to drill a hole and glue a brad or stiff wire into a leg. In photo 5, the golfers began life as hors d’oeuvres knives. On the day of the photo I found them chest deep in a
quicksand-like putting green. Rescuing them brought a bit of “grass” up around them for an amusing scene augmented
by wildlife.

The theory of relativity, where mini-groundcovers are concerned, states that if it looks right, it is right. And yet, so many outdoor modelers fret needlessly, wanting it to look like the sprayed-on green sawdust one sees on indoor layouts.

Here’s another trick. Where you want to model low, green cover near buildings, figures, or track, incorporate one-third or more sand or gravel into your soil around those areas to lessen the nutrients available for roots. This should stunt the growth. If that doesn’t work, use compacted gravel soaked in glue water (one part concrete-bonding adhesive to three parts water) and nothing will grow there for quite a while. Other fixes: put a plank or extra gravel under a sinking building when it gets buried; pull out groundcover by its roots around objects; or cut away chunks of the mat with a knife and transplant the divisions in bare spots. When groundcover gets too tall, it takes just a few minutes per square yard to shear it with battery-powered clippers.

Where’d ya get those creepers?

A groundcover website that has its own search engine to help you find just the right low plant for your needs, whether it be zone, soil, or sun conditions, is www.jeeperscreepers.info. You can search for plant use, such as pathway, wall, or lawn replacement. After picking a plant, click on “More information” for growing conditions, larger photo, height, rate of spread, etc. It is handy to know that if I had to find miniature plants for interior Alaska’s Zone 1, I could use crowberry (photo 6), a rugged mat I’ve seen growing on the rocky Maine coast. Specializing in rock-garden plants is www.rockstarplants.com, with a helpful advanced search engine.

I identified a familiar plant online at Jeepers Creepers that is literally a weed in northern California. I’ve wanted to identify it for over 10 years—it’s turkey tangle fogfruit (I kid you not). It makes a tough mat, flowering all summer, but I was afraid to try it in the railway garden because it had not been legitimized in print! Then I saw a listed plant that I know to be a wildflower in Maine, growing in lawns and meadows—mountain bluets, listed as 4-6" high—but I never saw the tiny blue flowers reach more
than 2-3" high.

It’s funny how a “weed” here or there makes an exotic “groundcover” somewhere else. It’s also odd that USDA Hardiness Zones listed on various nursery websites or in garden books can be so contradictory. One will say “Zones 1 to 9” and another “Zones 5 to 8” for the same species.

In Chart 1, the listed Zones have been double-checked but they come with no guarantees. Because of micro-climates
and varied gardening practices, I suspect that zones are not intentionally misleading but represent successful gardeners’ reports. Your local nursery should know what works in your area but may be limited in choices. If you garden on the edge of the listed Zones, protect that plant accordingly. For example, if you live in Zone 4 and buy a Zone 4-9 plant, know that you are gardening on the edge of its range.

Another website to try is www.stepables.com for 160 non-lawn groundcovers. I like to search at botanical gardens where labeled plants have wintered over for years. Online you can swap seeds at www.alpinegardensociety.net

Some of us are lucky enough to have moss (photo 7). Blend scraped moss with buttermilk and spread your own. Or purchase true moss sheets and moss “milkshake” at www.mossacres.com/products.asp  Or just let nature change the moist, shady areas seasonally without effort.

Downloadable File(s)

On Cecil’s Sparta & Shelby Railroad, the “grass” is Lysimachia japonica ‘Minutissima’.
Cecil Easterday
Woolly thyme makes a pretty purple wildflower field in spring. To keep a low profile, spent flower heads should be shorn before they turn gray.
Ray Turner
Shown are both the purple brass buttons and miniature brass buttons so you can see the size comparison.
Sue Piper
Frank is looking for a groundcover to replace the burned-out section of baby tears over the tunnel.
Frank Lucas
Regional gardening reports

All zones listed are USDA Hardiness Zones (For more information on mentioned plants see the chart in “Greening your railway.”)

Question: In your experience as railroad gardeners, what are your most effective, yet easy to grow, low groundcovers?

Cecil Easterday
Near Columbus Ohio, Zone 5
Micro lawns
Lysimachia japonica ‘Minutissima’ is compact, about 1⁄2" high, has very tiny leaves, spreads but is not invasive (easy to pull out if it infringes on track space), does well in sun or partial shade, and doesn’t mind drought. In early summer, it is covered with tiny yellow flowers. This is my favorite to use for turfgrass. Other plants that have grown well as groundcovers near buildings are Ophiopogon japonicus ‘Nipon’, Sedum ‘Hispanica’, Leptinella ‘Platt’s Black’ (dark, almost black), and Leptinella minor (green). Acaena microphylla is aggressive but also great if you have the room for it to roam. A lot of the thymes work for grass or for fields. Thymus praecox will even grow in the shade. Creeping red thyme (Thymus serpyllum coccineus) needs full sun and has a fantastic bloom. [Leptinella was formerly Cotula. —NN]

Ray Turner
San Jose, California, Zone 9
No thyme to mow
I do like woolly thyme, but my favorite groundcover is Elfin thyme (Thymus serpyllum ‘Elfin’). It grows and stays very low to the ground (typically 1⁄4"). It has the tiniest leaves I’ve seen on any thyme and pretty purple flowers—very much in scale with the railroad. Thymes in general are hardy and easy to grow, which is nice for folks like me with a brown thumb. Look at www.rainyside.com/features/plant_gallery/herbs/Thymus_Elfin.html. This web page discusses the culture of Elfin thyme.

Sue Piper
Near San Diego, California, Zone 10
Good, better, best!
Over the past several years I’ve tried every groundcover I could find that doesn’t need a lot of shade to survive. I’ve planted mosses, including the terribly invasive baby tears and the pesky, returning, spindly Irish and Scotch varieties. Of the many types of thyme, Elfin thyme is a favorite but is limited to certain areas due its mounding growth habit. Miniature rush is beautiful when first planted, but really does spread like wildfire and is extremely difficult to eliminate. Corsican mint and blue star creeper are also lovely but eventually overtake the area, track and all.

I’ve had the most success with the New Zealand brass buttons, of which there are several varieties available. Named for their golden button flowers, their leaves look like miniature ferns with actual mini “fronds.” Purple brass buttons (Leptinella purpurea) has fronds about 1⁄2" to 3⁄4" long that range in color from green to burgundy during the year. Miniature brass buttons (L. gruveri) has rich, lush green fronds only 1⁄8" to 3⁄16" long, perfect for mini greenscaping scenes, stays very low to the ground, and is easily contained by simply pinching back any stray runners. It may die back some in extremely hot or cold spells but always seems to come back denser and prettier than before.

Frank Lucas
Pleasant Hill, California, Zone 9
Crying for shade
Baby tears was the first thing we planted four years ago. We used plugs and they filled in quickly, producing a nice, quiet, uncluttered effect.

They can be a little finicky. They need water and like shade. In the picture you can see how the plant is flourishing only on the left side, which is shaded by the fence. The area above the tunnel gets direct sun. I may have to re-plant that area.


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