University of Vermont Extension 
Department of Plant and Soil Science

Anytime News Article

PERENNIALS FOR SHADE

Dr. Leonard Perry, Extension Professor
University of Vermont
 
 
Whether you have a mainly wooded landscape, or live in a neighborhood where the trees have matured into a dense canopy, there are some hardy herbaceous perennials you can grow under them successfully.  Allegheny spurge, Cinnamon fern, barrenwort, foamflower, astilbe, hostas, bigroot geranium, and Japanese forest grass all are adapted to a shady habitat.  These all need a well-drained soil, and are hardy to at least USDA zone 4 (average annual minimum temperature of –20 to –30 degrees F). 

Allegheny spurge (Pachysandra procumbens), although native to the southeastern U.S. is hardy in the north. It is semi-evergreen, and related to the more aggressive, common, and non-native Japanese spurge.  Its green leaves are only about three inches high with the white flower spikes in May just above the leaves.  Plant it in part to full shade, and cut back leaves in spring if they are brown.

Cinnamon fern (Osmunda cinnamomea) is so named from the upright cinnamon-colored spikes that bear the spores (like seeds for ferns).  The fuzz from these may be used by hummingbirds to line their nests.  The long fern leaves are upright in a clump two to five feet tall.  This native fern prefers moist shade, either full to part shade.  It is effective in masses, or as a backdrop for other perennials.

Barrenwort (Epimedium) is a great group of low maintenance perennials, native mainly to China.  The plants only get about a foot high, having small flowers somewhat resembling a columbine.  Flowers come in many colors, depending on cultivar (cultivated variety), from reds and pinks to whites and yellows.  Leaves can have an attractive reddish cast or margins when they emerge in the spring, and sometimes in the fall.  Water well to establish, but once established plants will tolerate drought.  Morning sun and afternoon shade is best.

Foamflower (Tiarella) is a native low perennial, leaves under a foot high and flower spikes (generally white or pinkish) in early summer getting up to a foot high.  Most form clumps, although some selections spread into effective groundcovers.  Many cultivars have been released in recent years having all manner of leaf shapes and colorations—their main attraction.  They tolerate dry soil once established, and grow well in part shade but tolerate full shade.

False spirea (Astilbe) prefers bright to part shade, and really needs a moist soil.  If it dries out, the leaves turn brown and wont recover.  Dry plants may not die, unless young or prolonged drought, but may not send up new shoots until next year unless they die back early in the season. Many cultivars exist of this perennial, with the characteristic two to three foot dense flowerheads in pinks, reds, or whites.  They are effective massed, or mixed in shade borders with other perennials.

Funkia or plantain lily (Hosta) are one of the most popular and easiest to grow perennials.  There are hundreds of cultivars, from six inches high and wide to three feet high and five feet or more wide.  Leaves come in many color variations, from solids to mottled to contrasting margins, in creams, whites, various greens and blues.  Some leaves are plain, others rippled or textured.  They withstand full shade and compete well with tree roots in dry conditions. Most have flower spikes in late summer above the leaves in whites to purples, often fragrant.   The main pest is slugs under moist conditions, and deer may browse the leaves.
 
Perennial geraniums are usually thought of for full sun, but several such as the wood cranesbill (Geranium sylvaticum) and bigroot geranium (G. maccrorhizum) do well in part to dappled shade.  They tolerate drought once established, the bigroot geranium wilting less in shade than it does when dry in hot sun.  Woodland cranesbill has purple flowers in late spring, while the bigroot geranium has pink or white flowers in summer. Leaves of the latter turn reddish in the fall.

Most ornamental grasses need full sun, the Japanese forest or Hakone grass (Hakonechloa) being an exception.  Usually you see one of the yellow leaved cultivars, ‘Aureola’ with its wide bright yellow leaf margins being common and a good choice.  Only getting a foot or slightly more high, this perennial can spread into a several foot wide clump under good conditions with moist soil.  Leaves arch, simulating a cascading waterfall, making it effective on sloping terrain and in masses.  It is a good choice to brighten up part to full shade (less color in full shade), but is generally only hardy to USDA zone 5 (-10 to –20F average minimum). 

Look at local perennial nurseries and garden outlets for these shade perennials, as well as others such as dead nettle (Lamium), which is not horrid as its name sounds, lungwort (Pulmonaria), and coralbells (Heuchera).   Lamium tolerates dry soils and bright to full shade.  Lungwort prefers moist soils, especially when young, but can tolerate occasional drought when mature.  It grows well in dappled, bright, or part shade.  Coralbells can grow in full sun if sufficient moisture, but in part shade prefers drier soils. All these three groups have attractive flowers and leaves.
     

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