Groundcovers: Grand to Aggressive

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This black mondo brings attention to subtly variegated plants.

Groundcovers are often suggested as solutions for sites where turfgrass won’t grow, or for places that are difficult to mow. As useful as that suggestion is, I feel like it sells them a little short. They can absolutely sparkle as contributors to overall garden design, providing the theme that pulls together a disparate collection of plants, lead you through a landscape, or provide intriguing colorful or textural counterpoints to other plants.

This bank of mondo grass does a good job of covering soil in an enclosed bed where it cannot run into infinity.

I also have to quibble a bit on a commonly held belief that groundcovers are a low maintenance solution. Sometimes they are, and often not. Choosing those that don’t run rampant is paramount. When I am asked to recommend a fast-growing groundcover, I first spill my misgivings. “Fast” choices often turn out to be foe instead of friend. They don’t know to stop covering ground where the gardener’s mission ended.

I prefer low growing evergreen plants that stay in discreet clumps or spread very slowly. It is more expensive on the front end to get full coverage, but as I grow older the more important economy concerns how I use my time and my poor stiffening body.

 

The other problem is that often weeds are happy to cohabitate with groundcovers, and not just during establishment. A bed of Vinca major surrounds an ancient tulip poplar on our grounds, planted decades before I started this job. Birds, defecating the seeds of their favored fruits have “planted” Virginia creeper, poison ivy (yes birds eat poison ivy fruit), wild cherry, hackberry, honeysuckle and the horrid thug Chinese privet. The only solution is to hand weed, as any herbicide that will kill them will also kill the groundcover. (It is surrounded by lawn, so at least stays put.)

This dense bed of Vinca major was happy to host seedlings of poison ivy, hackberry, Virginia creeper, smilax, wild grape and privet.

Having a thick cover of plants does reduce the number of weeds, but this bed is evidence that establishing a vigorous groundcover does not provide a situation that requires no maintenance. If weeding is necessary, it is  more interesting to use a diversity of plants that don’t run, or at least spread at a manageable creep.

An exception is the bed surrounded on all sides by concrete or other inhospitable surface. An understory of mondo grass or the running form of monkey grass Liriope spicata  will fill these areas with evergreen grassy texture. Look Ma, no mulch!  I would still avoid fast spreading vining type groundcovers in these situations, as they are wont to climb on and overwhelm taller perennials, shrubs or even trees. English ivy is famous for this and the near-equally problematic wintercreeper euonymus.

Dwarf forms of mondo grass move so slowly, using it where it is not captured by hardscape is not a problem, and the black mondo is so slow in my climate, that I think sometimes it gradually vanishes rather than vanquishes. Maybe I have yet to find its happy spot in my landscape.

This gives a good opportunity to segue into more detailed design opportunities. I fell for black mondo years ago on my travels, but few use it so masterfully as fellow Tennessean Faye Beck. She stages it for intriguing contrast under bright or bold foliaged plants. It is the dark underscore she uses to call attention to some of her most glittering treasures.

Dwarf golden sweet flag’s furry cuteness belies its durability. The size 10 peasant feet belong to me and provide good scale.

Flip that concept and use the dwarf golden sweet flag under purple heuchera, big blue hostas, or dark ninebarks. The swirled, tufted “cowlick” habit of this diminutive plant pulls me into a crouch as I simply must stroke it, and it is as soft as it appears. Soft does not translate to delicate as it is quite durable (to Zone 5) if provided shade and moisture. A wet site is necessary to support it in full sun. Bless its tiny heart, it has to be sturdy to support its giant name Acorus gramineus ‘Minimus Aureus’!

This idea of using the brighter ground covers to call out to you can be used effectively on the larger scale as well. Broad brush strokes can pull you around curves in garden paths or simply pull your eye toward a destination that warrants exploration. Please though, reconsider using them to “outline” a sidewalk, driveway or bed. I admit this use pulls a snobbish sigh from me for its predictability.

This sweep of ‘Ogon’ sweet flag pulls you on to explore more of the landscape.

Another friend that shares his clever design tricks is Jimmy Williams in Paris TN, with his tongue-in-cheek garden “Tennessee Dixter”.  Jimmy will take single clump of a common groundcover and use it as a design element with other perennials to form charming vignettes.   The ordinary liriope ‘Silvery Sunproof’ strikes grassy grace when used this way, a beauty obscured when used en masse. Less common, but another fabulous plant used singly is the golden liriope ‘Peedee Ingot’. This plant has become one of my favorites in container combinations. Somehow I must get over the feeling that I need to defend falling in love with a “monkey grass”.

A single clump of ‘Peedee Ingot’ liriope golden monkey grass stars in this composition.

Maybe you are far ahead of me in skulking the groundcover areas of the garden centers with thoughts of thrilling design elements instead of pedestrian solutions. Show me! I’m a little slow, but I’m teachable…

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Carol Reese

Carol Reese is an Extension Horticulture Specialist housed at the University of Tennessee’s West Tennessee AgResearch and Education Center in Jackson. She is a nationally-known speaker, blending equal parts gardening knowledge, natural lore, and quirky humor.

Carol is the gardening and nature columnist for several newspapers, as well as a contributor to several gardening magazines. She was the Q&A columnist for Horticulture Magazine for several years.

Her B.S. and M.S. in Horticulture are from Mississippi State University, and she could also add her Ph.D. if she “had ever written that damn dissertation!” While there, she taught classes in Plant Materials, and co-taught Landscape Design for non-LA majors alongside a “real” landscape architect.

She attributes her love of horticulture to being raised on a farm by generations of plant nuts, including a grandfather who dynamited his garden spot each spring to “break up his hard pan”. Carol’s very personal appreciation of natural lore is at least partially a result of her near daily rambles through the wild areas near her home with her motley collection of mutts, also known as the strong-willed breed of “Amalgamations.”

 

2 COMMENTS

  1. I would urge people to be aware of what plants are invasive in their area. I had to have a company spray the acre of vinca minor planted near the house by former owners. It had spread incredibly. I live near natural areas and didn’t want it spreading further. The same applies to many other plants as well. Our native wild ginger is a nice ground cover. Plumbago is also. Not so for sweet woodruff or Lamium (dead nettle) both can be invasive as is lily of the valley.

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