Moss Phlox or Thrift Provides a Blanket of Spring Color

“Common” names often cause confusion about plant identity. The spring-flowering groundcover at my childhood home was always called Thrift. It wasn’t until I started working at a garden nursery that I learned that its true identity was Phlox subulata, pronounced FLOCKS sub-yoo-LAH-tah. Then a customer asked for Thrift but meant Armeria, also known as Thrift. The two Thrifts are completely unrelated. Armeria juniperifolia (juniper-leaved thrift) and Armeria maritima (sea thrift) grow up to one foot tall. One has sharp foliage like a juniper while the other has grassy-like foliage. Both are perennial in zones 4-9, and are salt-tolerant. Their flowers remind me of Scabiosa. The focus of today’s blog is Phlox subulata, an old-fashioned southern standby.

Phlox subulata is also known as Creeping Phlox, Moss Phlox, Rock Phlox, and Thrift. This evergreen perennial reaches only six inches tall, at most. It forms a tight mat of needle-like foliage that works well as a groundcover and is frequently used in combination with large rocks. The flowers are small (3/4 inch across, with five petals) but so numerous that they conceal the leaves, appearing like a blanket of color. Thrift is blooming right now in my area, with showy mats of pink, rose, white, light blue, or lavender flowers. It is often used on steep banks or slopes, where it will self-seed and spread to cover uneven terrain and prevent erosion. Give Thrift full sun or part sun in acidic soil. It requires little maintenance beyond a little thinning if it becomes so congested that it starts choking itself.

Phlox subulata is native to the US and will grow in zones 3-9. It is rarely bothered by insects or diseases. Deer do not normally browse Thrift; the flowers are favored by hummingbirds, bees, and butterflies.

I planted a couple of these Phlox subulata under a new redbud (Cercis chinensis ‘Don Egolf’) last year. The color of the flowers is a near-match to the color of the tree’s blooms. They flower at the same time, and are neighbors to a yellow Forsythia, which provides a nice color contrast.

This thick mat of Thrift (Phlox subulata) has spread to replace grasses or weeds that might have grown under this fence, eliminating hand-weeding or string-trimming.

Pachysandra as Evergreen Groundcover

One of my former neighbors persisted in trying to grow Pachysandra as a groundcover under his oak trees. Tray after tray of plugs arrived and were planted in spring, only to die by fall. He finally relinquished his preferred plan and planted variegated Bishop’s Weed (Aegopodium podagraria) instead. Also called Goutweed, Snow On The Mountain, or Ground Elder, Bishop’s Weed is an aggressive, invasive groundcover that is difficult to eradicate once established. I suggest you avoid it.  Given the neighbor’s difficulty in growing Pachysandra, imagine my surprise last year when I stumbled across a large (forty feet by seventy feet) patch of it growing on a woodland bank near my creek. In May, it looked like a large emerald blanket, and even draped over the creek bank like a curtain. This week, it shows the ravages of extreme cold and too much rain, but it is still an effective groundcover. I have no doubt that it will return to its former glory when temperatures warm in spring.

 There are two species of Pachysandra. Allegheny Spurge (Pachysandra procumbens, pronounced pak-ih-SAN-drah pro-KUM-benz) is native to the southeast. It is evergreen to semi-evergreen, and cold hardy in zones 7-8. It grows in rich, moist, acidic soil, in dappled shade to full shade. It is not invasive. This is the variety that is living happily in my woodlands. It averages nine inches tall and has not been browsed by deer, despite heavy populations in this area.

 Like other plants we have adopted from the Land of the Rising Sun, Japanese Pachysandra (Pachysandra terminalis, pronounced pak-ih-SAN-drah ter-min-AL-iss) tolerates a wide range of temperatures (zones 5b-9a) and is a more aggressive grower than the native type. It may grow up to a foot tall but is typically shorter, and spreads by underground rhizomes. ‘Green Sheen’ is especially heat tolerant. ‘Green Carpet’ is a mounded uniform form that lends itself to edging for shady beds.

 Both the above species bloom in spring, but the flowers are not particularly eye-catching. Bees love them. Pachysandra is in the same family as Boxwood and shares some of its susceptibility to scale, leaf spots, and root rot. Don’t overwater, and if dead or diseases patches become apparent, remove them before the problem spreads to the rest of the bed.

Big box stores usually sell Pachysandra in trays of 2-inch plugs. Tease them apart carefully to avoid damaging tender roots. Place plugs six inches apart for rapid coverage, or up to a foot apart. Even at the wider spacing, ground coverage should be complete in three years. when grown in moist shade and fertile soil. Be careful to avoid constantly wet soils.

Purple Heart Is An Easy, Colorful Perennial

Tradescantia pallida..

Recent warm weather started the garden-planning process for many of us. If you are seeking a quick-growing,, easy perennial for a splash of violet, consider Purple Heart.

Tradescantia pallida (pronounced trad-es-KAN-tee-uh PAL-lid-duh), commonly called Purple Heart, has striking purple leaves. It is grown for its rich foliage, but it also has delicate, three-petaled pink or purple flowers. It is a popular choice for gardens and flower beds, and can be grown as an annual or perennial depending on the climate, or as a houseplant anywhere.

Purple Heart can reach up to eighteen inches tall and twenty-four inches wide, with a trailing habit. It prefers well-drained soil and partial shade. It will survive in full sun if given occasional irrigation. More sun results in greater color intensity of leaves. Plants are drought-tolerant once established. They are undemanding in soil type or texture.

Propagation of Purple Heart is easy from stem cuttings. Cuttings can be taken in the spring or summer rooted in a mixture of sand and peat moss. For those with no desire to set up a propagation area, fair success can be obtained by taking stem cuttings and inserting them into the soil where the mother plant is growing. Remove any leaves that will be below ground level, and ensure that soil covers a node (where a leaf emerged from the stem). Keep soil damp and at least half the cuttings will strike roots.

Plants are hardy zones 7-11. A hard frost will turn all top growth into mush, which can be removed any time before spring. In the cooler zones, a light mulch (pine needles) will help protect the roots and ensure its return. New growth will emerge as soon as weather warms in the spring. Purple Heart is not particularly susceptible to diseases or pests, including deer. It provides a beautiful contrast to yellow or pink flowers. Its undemanding nature and rapid growth makes it a good choice for new gardeners.

This border of Purple Heart is located outside a church gymnasium in an area that receives full morning sun. It gets no irrigation or care, and it looks great, year after year.

Ajuga

Few perennials look great through the entire year. In the Mary Snoddy garden, a patch of Ajuga (pronounced ah-JOO-gah) has survived all manner of abuse: being trampled underfoot during our home renovation, record-breaking rain, record-breaking cold, full sun in what used to be full shade, and general disrespect. It does not look great, but I marvel at the fact it survived at all. We have had two days of warm sun, and it is pushing out fresh new leaves.

Ajuga reptans is an easily grown, aggressive, short groundcover. It is available in shades of bright chartreuse, deepest burgundy or chocolate, and a lovely sage green, white, rose combination. Textures vary from fine blades (‘Chocolate Chip’) or broad leaf (‘Black Scallop’). Newer cultivars broaden color choices to bronze, yellow, orange, and red. Look for the Feathered Friends™ series for something truly unusual.

Ajugas thrive in partial sun or shade. Blue flowers in spring are a bonus. These undemanding groundcovers spread quickly, giving rise to some gardeners’ assessment of the plant as invasive. (It is a member of the mint family). It will grow and even thrive in many situations where other plants, including grass, won’t grow: deep shade, dry soil, or under Black Walnut trees. It will tolerate minor foot traffic. Plants can be so vigorous that congested areas die. Prevent this by division. Ajuga is resistant to damage from deer and rabbits. Other than dieback from congestions, their only problem is root-rot when placed in wet soils.

Ajuga reptans ‘Burgundy Glow’ has a lovely pink and white variegation that lights up daker areas in the shade garden.

Fine leaf Ajuga reptans ‘Chocolate Chip’ softens the edges of a brick walkway.

Golden Creeping Jenny for Groundcover or Containers

A good groundcover is like the piece of lettuce under a serving of chicken salad on a luncheon plate. It makes the star of the meal look better without drawing attention to itself. Groundcover plants do not receive as much attention as shrubs, annuals, or perennials. They just do their job, providing an under-dressing to feature plants while spreading to cover bare soil, reducing erosion, and shading out weeds. One that defies tradition and draws attention to itself is Lysmachia nummularia ‘Aurea,’ widely known as Creeping Jenny. 

Creeping Jenny will grow in sun, part shade or even mostly shade. Its bright chartreuse hue makes its neighbors look better by contrast. Leaf color will be more golden in areas with bright sun and more lime green in areas with mostly shade. It will spread vigorously, and is considered invasive in some states. If this concerns you, plant it where it is restrained by walkways or metal edging. The vines grow almost flat (three inches or less) and form roots wherever stems touch soil. This rooting habit means they can bounce back from occasional damage from foot traffic or pets (like the black kitten in the accompanying photograph). It will drape over walls like a chartreuse curtain. Plants rarely grow upward more than an inch or two, so there is no concern about it creeping up trees. If the plant grows outside its intended area, the fine stems are easily pruned with a pair of utility scissors.

Lysmachia nummularia ‘Aurea’ (lis-uh-MAK-ee-ah num-ew-LAH-ree-uh, but internet sources offer multiple suggested pronunciations) tolerates heat and humidity. It looks best when grown in rich soil with moderate moisture. It will grow slower in lean soils and with less moisture. The vine-like mat is perennial in zones 3 through 8. Winter cold may make some of the leaves shed or take on a reddish hue, but it recovers quickly with the return of warm weather.

Creeping Jenny can be used in containers, either as a single specimen in a hanging basket or in a mixed planting, where it will cascade over the rim of the planter. It looks especially nice at the edges of water features and makes a good partner to upright sedges and ferns. If you choose to pair this one with a variegated plant, choose a companion whose variegation color is in the yellow family (as opposed to white or ivory). It complements most flower colors (pinks, reds, oranges, purple) but does not play well with yellow flowers. Creeping Jenny rarely blooms. Its small, golden flowers are easy to miss against its foliage.

A Groundcover as Container Specimen

When is a groundcover not used as a live mulch? When it is a container plant, of course. Lysmachia congestiflora ‘Walkabout Sunset’ has a beautiful, multi-colored leaf and clusters of bright yellow blooms. Initially the common name, Loosestrife, frightened me away from using this plant because I feared it might be invasive. I’m happy to report that this is not the case.

Several cultivars are available. All are low growing (to six inches) and will spread readily since they root wherever stem touches soil. This spreading habit makes it a great choice for edging in-ground water features. Lysmachia is a semi-evergreen perennial in zones 7b to 9a  In my 7b garden, I find ‘Walkabout Sunset’ sheds most leaves and looks dead by late winter but makes a rapid recovery when spring arrives. It will not tolerate temperatures below 15 degrees, so I take a small cutting in autumn and overwinter it in the greenhouse as added insurance against plant loss.

‘Walkabout Sunset’ performs best in part-sun, with a little shade in the hottest part of the day. It prefers damp to wet soil and is undemanding as to soil pH. I sited a potted specimen in full sun and found that it needed more additional water than I was willing to donate, so I relocated it to the raised portion of a birdbath. This solution kept the plant roots damp and gave birds and insects a place to perch when they visited the water source. Everyone was happy.

‘Walkabout Sunset’ is equally attractive when used as a sole container specimen or as an undercover to a taller plant. The variegated leaves have a blue-green stripe that pairs well with a similarly toned container.

You will note that I did not include the pronunciation above, as I normally do. Here goes: ly-si-MAK-ee-uh kon-jes-tih-FLOR-uh. I have observed that some well-known plant experts pronounce the third syllable with a long A while other make it a short A. I thought it would be easier to stick with the cultivar name, but then I found some plants tagged as ‘Walkabout Sunset’ and others as ‘Outback Sunset’ or ‘Waikiki Sunset.’ Are they the same? I cannot tell. What I can tell is that ‘Persian Chocolate’ has purple-ish foliage. Can’t wait to try it in a container with pink Begonias.

Foliage color mirrors container

Birdbath keeps soil wet

New Ajugas, New Colors

It is freezing outside. The wind is moaning like a banshee with a hangover. And I am indoors, fireside, with a cat on my feet and a lap full of nursery catalogs. It’s always fun to see the year’s newest seed and plant introductions and to read all the descriptions. A catalog from a seed company in South Carolina. has a whopping 184 entries for tomatoes. How can growers find 184 different ways to describe a tomato? And yet, they do.

Among the new plants for 2021 is an entire series of Ajuga reptans. ‘Feathered Friends’ encompasses seven new cultivars with golden, bronze or almost-black leaves. My heart beat a little faster when I saw Ajuga ‘Noble Nightingale.’ Some interior decorators recommend a touch of black in each room. A touch of black or almost black can elevate a so-so container combination to wow. Black mondo grass (Ophiopogon planiscapus 'Nigrescens') has been my go-to plant for containers, but ‘Noble Nightingale’ is only four inches tall, with a spread up to 18 inches. I can envision it with Euphorbia ‘Diamond Frost’ and something pink — Begonias or Caladiums. ‘Cordial Canary’ has golden yellow foliage, unlike any other Ajuga. ‘Parrot Paradise’ has leaves with shades of yellow, orange and red. From a distance, it reads as bronze.

Ajuga (common name is Bugleweed or Carpetweed) is easily grown in partial sun or shade. It will tolerate some drought. Blue flowers are a bonus. These undemanding groundcovers spread quickly, giving rise to some gardeners’ assessment of the plant as invasive. (It is a member of the mint family). It will grow and even thrive in many situations where other plants, including grass, won’t grow such as deep shade, dry soil, or under Black Walnut trees. It will tolerate minor foot traffic. Plants can be so vigorous that congested areas die. Prevent this by division. Ajuga is resistant to damage from deer and rabbits. Other than dieback from congestions, their only problem is root-rot when placed in wet soils.

The Mary Snoddy garden features ‘Burgundy Glow’ and ‘Black Scallop’ but these new cultivars are alluring. The above-mentioned ‘Feathered Friends’ is offered exclusively by Mast Young Plants. Here is a link to their site, so you can see photos of these beautiful new foliage colors: Ajugas

This photo of Ajuga ‘Black Scallop’ was taken February 3, proving that this groundcover for shade can look as good in mid-winter as it does during the warmer months. The almost-black foliage looks wonderful when paired with chartreuse, such as Lysimachia aurea, “Creeping Jenny” or rose shades, such as a bronze-leaf wax begonia with pink flowers..

Ajuga ‘Burgundy Glow’ lights up a dark area.

A planting of Ajuga ‘Chocolate Chip’ along a walkway at Hatcher Garden and Woodland Preserve. (Photographer is unknown, unfortunately.) The shiny, rounded leaves offer beautiful contrast to the delicate fern fronds and the rough granite stones.

A new planting of ‘Black Scallop’ Ajuga pops against the chartreuse foliage of Talinum (“Jewels of Opar” and the rounded leaves of several Hostas. It will eventually spread to cover all the pine needle mulch.