Wandering Wire Vine
It's hard to find room for a plant which has neither showy flowers nor evergreen leaves to boast of, however, Muehlenbeckia deserves a spot in many gardens. It shines planted alone, as the finely textured, black stems are the perfect foil for the astonishingly round, glossy leaves. It is both tough enough to look after itself and fast enough to be noticed despite its diminutive height, plus it quickly forms a dense mat which weeds are unlikely to penetrate.
Why mulch your rose garden with bark dust when you could mulch it with wire vine? That long, grey, unbroken retaining wall could look more like a living waterfall in just a couple years. How about a hanging basket? I bet it would trail to the ground in one season. Try it in a container with Black Mondo Grass (Ophiopogon 'Nigrescens') and an upright Flowering Maple (Abutilon sp.) for a show stopping container for part shade that blooms from May until December.
It's the leaves' unique ability to stay in excellent condition from March through November (or later) which makes all these uses suitable, no cutting back or grooming is generally required.
Some varieties you can find at Portland Nursery include:
Architectural round leaves give an effective illusion of water flowing when trailing out the side of a pot or over a rock wall. Black stems provide excellent contrast for the glossy, mid-green leaves. 4"H x 20-30'W. Z7
Muehlenbeckia axillaris (syn. M. 'Nana')
Tiny little leaves make it look like a delicate little rockery plant, but don't plant it in a small space, it spreads just as fast as its larger leafed relatives (up to 20' wide). Leaves turn bronzy before dropping in late fall/early winter. Z7
Muehlenbeckia 'Big Leaf'
This variety is of unknown parentage, but is perhaps a large leafed selection of M. complexa. It's certainly very similar to that species except for the larger leaves. Z7
Muehlenbeckia complexa var. microphylla
Leaf size is bigger than M. axillaris but smaller than M. complexa. Compact habit. Z7
Common Name: Wire Vine, Creeping Wire Vine, Maidenhair Vine
Origin: The genus Muehlenbeckia consists of 20 species native to Australia, New Zealand, South America, and New Guinea. Only the species M. axillaris and M. complexa are common garden plants, and both are native to New Zealand.
Culture: Many are frost tender, however, M. axillaris and M. complexa are hardy to USDA zone 7 (0-10 degrees). In New Zealand, both are woodland plants preferring dappled shade, but here in the Pacific Northwest we have much less intense light, and both grow equally well in full sun or quite a bit of shade. Any reasonably well drained soil will suit these agreeable groundcovers, and drought, salt spray, and wind are all tolerated with good grace.
Maintenance: When sited appropriately, both M. axillaris and M. complexa are fast spreading, and quite capable of vining over obstacles or up trellises, so some cutting back to keep them in bounds may be required. Otherwise, these tough plants take care of themselves if watered deeply about once a week for the first couple seasons.
Pest and Disease: Generally none, however, bacterial root rot can kill even established patches if the soil is poorly drained and conditions are unusually wet. There is no treatment once damage is observed, the key lies in choosing the proper site and amending the soil at planting time.