One of the best, in my opinion, are any of the epimediums. There are many species
and forms of this extremely adaptable plant to choose from, ranging from 10” to
over 2’ tall. The somewhat leathery leaves are divided into 3 to 9 crisp, heart-shaped
leaflets on thin wiry stems. Panicles of small delicate flowers with elongated spurs
dangle like little columbines above the emerging foliage in spring. The flowers can
be yellow, white, pinkish-lavender, orange, or red/white, often with contrasting
colors of petals and sepals. There are spreading forms with evergreen leaves that
turn bronzy or reddish in winter, and deciduous, clumping forms with a pleasing apricot-yellow
fall color. Hardy and long lived (there are some 50 year old clumps in a New York
garden), they have the distinct advantage of being able to compete with roots of
nearby trees and shrubs. Epimediums will grow in considerable shade but tolerate
sun with sufficient spring watering. Following are some of the more readily available
varieties: bright yellow E. pinnata ssp. colchicumand soft yellow E. versicolor
‘Sulphureum’ are evergreen spreading forms; E. x ‘Rubrum’ is a semi-evergreen clumper
with red/ white color and reddish fall/ winter foliage; E. grandiflorum has the
largest flowers of the group, about 1” across with long graceful spurs, usually white,
deciduous and clumping; E. x youngianum ‘Roseum’ (pink) or‘Niveum’ (white) have a
more delicate wildflower charm. Any of the clumping forms can be planted ‘en masse’
to eventually fill in the allotted space. Our native Vancouveria hexandra (Inside-Out
Flower) is very closely related to Epimedium, but has more delicate leaflets and
sprays of small white flowers to 12”. It fills the same niche under similar conditions.
It will also tolerate root competition and forms a weed smothering mat with time.
Although deciduous, it is an excellent and attractive choice. Epimediums are members
of the Berberidaceae Family along with such shrubby genera as Mahonia and Berberis,
and the herbaceous genera Achlys (Vanilla Leaf) and the east coast Jeffersonia.
To see exceptional stands of epimediums as groundcovers, be sure to visit ‘Bishops
Close’ in the spring.
NW native Oxalis oregana can be invasive, but is a good choice in the right situation.
Growing to about 6” high, the large clover-like leaves are almost translucent when
unfolding in early spring, especially pretty in the dappled sunlight beneath deciduous
trees. The flowers are pinkish white, but a fine form with extra large deep pink
flowers is available. An area under trees that is well drained and stays fairly
moist is a good spot to try a combination planting of Oxalis underplanted with deep
rooted tuberous plants such as Trillium and Erythronium. Try planting Oak Fern (Gymocarpium
dryopteris) Vanilla Leaf (Achlys triphylla) and Vancouveria hexandanearby and each
will find it’s own niche as they intertwine to form a cool tapestry of textures and
shades of green all summer long, following a quiet symphony of ephemeral spring bloom.
Oxalis ‘Wintergreen’ is new on the market, denser growing and deeper green, each
leaf ornamented with a diffuse central spot of silver, and purple beneath, studded
with bright rose-pink flowers. It also spreads, but not as widely as O. oregana.
It is evergreen and keeps a neat appearance all winter
Omphalodes verna (Blue eyed Mary), is an uncommon shade lover with low growing elongated
heart shaped leaves of mid-green and 6” clusters of flowers reminiscent of Forget-Me-Nots
in size and intensity of true blue. This plant spreads by runners, rooting at the
tips as it goes, eventually becoming a loose mat just a few inches high. It blooms
in early spring for about 6 to 8 weeks. For a pretty combination try combining O.
verna with yellow, cream, or pink Erythronium. The Erythronium easily come up through
the loose mat of Omphalodes and bloom at the same time, creating a charming garden
picture.
Gaultheria procumbens has smooth shiny oval leaves about 3” long and 1” wide. It
is perfectly evergreen and spreads at a nice pace to make a solid cover about 6”
high, excellent under shrubs such as rhododendrons. It is related to rhododendrons
and thrives under the same cultural conditions. The clusters of small pale pink urn
shaped flowers give way to long lasting large bright red berries. The flavor and
smell of the crushed berries give it the common name of Wintergreen. It is native
to the East Coast of the USA
Wild ginger is another option to consider . Our nativeA. caudatum is a fast and wide
spreader when happy. It has mid-green heart shaped leaves that lie almost at ground
level, and curious brownish red flowers nestled beneath the leaves, but worth looking
for. The roots and rhizomes of this plant smell and taste strongly of ginger. A.
europeum, European Wild Ginger, is perhaps an even better groundcover choice. It
has shiny, thick, dark green, heart shaped leaves, and is perfectly evergreen. It
spreads, but not as quickly, and it’s neatness of habit and density of growth make
this one a favorite.
Groundcovers do not necessarily have to be spreaders. Consider an underplanting
of hosta or pulmonaria. Hostas are deciduous shade lovers native to Asia, and are
quickly gaining favor for their hardiness, longevity and the multiplicity of forms
available. Hostas form neat rounded clumps of big, bold, lance to heart-shaped leaves
of varying shades of green. There are an abundance of striking variegated forms,
with streaks or splashes of gold, creamy yellow, or white, especially effective in
brightening up a shady spot. Hostas are exceptionally long lived, becoming more
impressive each year. There are varieties that rise no more than 2“ off the ground
and 4” across, to giants over 3’ high and 6’ across. A planting of hostas under
a tree or along the shady side of a building will quickly fill in to create a weed
smothering groundcover. Local nurseries are now stocking a wide selection, and if
that is not enough to satisfy, hundreds of cultivars can be found at some specialty
nurseries.
Pulmonaria (Lungwort) is also enjoying renewed popularity. Low growing and clump
forming, pulmonarias are excellent groundcovers when planted ‘en masse’. They have
elongated, broadly sword shaped leaves, some up to 2’ long and lying flat, some a
mere 8” and somewhat upright. They are commonly a deep rich green with varying degrees
of showy silver spotting on the leaves, with the rough texture typical of most plants
in the Borage family. The sprays of small flowers are usually of some shade of clear
blue, blooming in early to mid-spring. Some varieties have flowers with the interesting
trait of emerging pink and changing to blue, so that pink and blue flowers share
the same plant. There are also white flowered forms. New varieties are being bred
for mildew resistance, heavy silvering of leaves, (P. ’Ex Caliber’ is almost pure
silver), abundance of flower, and undulating leaf edges. P. longifolia ‘Bertram
Anderson’, P. ‘Roy Davidson’, and P. ‘Ex Caliber’ are all excellent choices. They
are semi-evergreen, only losing their leaves completely during the coldest winter.
Another plant, not usually thought of as a groundcover, but which suits the role
perfectly, is Helleborus orientalis (Lenten Rose), now more correctly considered
H. x hybridus. These plants have large, shiny, thick, dark green leaves deeply divided
into 5 or more leaflets. They are evergreen, grow to about 2’ tall, and each plant
will cover a space about 3’ x 3’ after a few years. Depending on the form, they
start to bloom in late winter to early spring. What we see as petals are actually
the sepals, and, fading slowly, will hold their ‘bloom’ for a very long time, sometimes
up to 2 months. The nodding cup shaped flowers are about 2” across and grow in clusters
just above the foliage. They can be white, pinkish or deep purple and are frequently
finely spotted. Much hybridizing and selecting is being done for flower form and
color, mostly in England and Germany, and hopefully we will soon have improved forms
to choose from. But for groundcover effect alone, the flowers are a bonus, incidental
to the rich green foliage effect. Good displays of H. x hybridus can be seen at
the Berry Garden.
There are many more possibilities. Consider a planting of ferns. Our native Sword
Fern is still one the best, although there are so many choices it is hard to choose
a favorite. New Heuchera varieties (Coral Bells) with robust leaves overlaid with
purple and silver will overwinter as tidy clumps, expand with luxurious foliage in
spring and bloom most of the spring and summer. Spreading woodland phlox (P. stolonifera)
will also do the job..
So let your imagination loose. Get ideas from the local Botanical gardens and from
the display gardens of the numerous specialty nurseries in the area. Seeing the
plants in a garden setting is a world apart from seeing them in small pots on the
nursery sales table.
