Shade in the garden is in no short supply. If it isn’t
shade from evergreens—usually our native Douglas firs (Pseudotsuga menziesii),
Western hemlocks (Tsuga heterophylla) and red cedars (Thuja plicata)—then it’s
deep shade from nearby buildings. Nature abhors a vacuum—so even in shade—bare
soil, left untended, usually fills up with unwanted plants.
Instead of leaving the weeds
to their own devices, why
not choose some shady characters that appreciate a little relief from the sun
and, at the same time, add charm, texture and form to the garden? In the top 10
of any gardener’s list for shade plants such as that should be Polygonatum.
as Solomon’s Seal, because the rhizomes
are marked with what looks like the official seal of King Solomon—comprises
species that are native to North America, Europe and Asia. They grow best in
part to full shade.
What draws us to these herbaceous perennials is their
elegance in the garden. Tall stems arise singly from underground rhizomes and
arch gracefully. Leaves are held on an almost horizontal plane, and the small
white flowers, which are bell or tube-shaped and often tipped in green, dangle
on delicate stems from leaf axils.
Polygonatum is either a member of the lily family
(Liliaceae) or the lily-of-the-valley family (Convallariaceae); it depends on
the whether you are a lumper (the former) or a splitter (the latter),
taxonomically speaking. You’ll find both family names in current literature,
reflecting the fact that plant classification is a lively and ongoing subject.
of names, several of the Polygonatum species
have variable names—for example, is it P. commutatum or P. biflorum var.
commutatum? And what about the giant Solomon’s Seal, often listed as P.
canaliculatum? Variability in size led to the long-held conclusion that these
were different species or at least distinct varieties of the same species.
it is. When described as separate species,
P. biflorum is said to grow to about three feet, while P. commutatum can get to
seven feet. It’s no wonder these weren’t considered the same. Even so, the
latest news is that the various names and groups of plants have all been
collected into the species P. biflorum, no matter how variable.
Known as the smooth
Solomon’s Seal, P. biflorum is the
most common North American native Solomon’s Seal to be found in our gardens. As
an American woodland plant, companions come to mind easily—shrubs such as
summersweet (Clethra alnifolia) and sweetshrub (Calycanthus floridus) and
perennials including the wood aster (Aster divarcatus) and mayapple
Although they grow in humus-rich soil with medium
moisture, most Polygonatum, once established, can carry through dry periods in
the summer, as long as they are planted in the shade. And a good mulch helps,
The species of Solomon’s Seal we are most familiar with
in the garden share similar characteristics: unbranched stems; alternate leaves
that are almost sessile (that is, almost attached directly to the stem without
a leaf stalk) with conspicuous veins that look almost parallel; small, pendant,
green-tinged white flowers that vary slightly in number (from one or two to a
few) according to species and cultivar.
Similarity in species shouldn’t be used
as an excuse to
have only one kind of Solomon’s Seal in the garden. They are far too useful for
that, and gardeners should consider a collection rather than a single
representative, much like we might do with Epimediums (which also make good
companions to Solomon’s Seal).
And although size and scale are important to consider,
even gardeners with small spaces shouldn’t shun some of the taller-growing
selections just because there doesn’t seem to be room. After all, we can’t fill
our gardens only with plants labeled ‘Nana’ or ‘Compacta’ or it will look like
we live in Lilliput. So, if that P. biflorum you bought grows a few feet taller
than you expected—let it rise out of a sea of hellebores. You’ll be the talk of
your garden club.
Dark blue berries develop by fall in P. biflorum as well
as in P. multiflorum and P. x hybridum (the latter being a cross between the
first two). The dark berries stand out against the yellow-gold fall foliage,
making the end of the year as decorative as the beginning.
The European species P. multiflorum
grows up to two feet
and has flowers that often appear only on the bottom half of the stems. The
hybrid between these two species—P. x hybridum—is (with typical hybrid vigor)
quick to take hold in the garden. Several cultivars of P. x hybridum are
listed, but not all are readily available. In literature, there is a double
named ‘Flore Pleno’, but searching online and in catalogs resulted in no
sources. The equally elusive ‘Nanum’ grows slightly smaller than normal (to
about 18 inches). The foliage of ‘Striatum’ (a cultivar that is available) is
irregularly edged in creamy white.
The fragrant Polygonatum odoratum ‘Variegatum’
beauty. Its dark red stems rise two to four feet, and the horizontal leaves are
delicately edged in white. Small white, pendant flowers appear in late spring
or early summer, followed by dark blue fruit. A colony of these lovelies in the
shade garden lighten any darkness.
The variegated fragrant Solomon’s Seal can
be listed as
P. odoratum var. thunbergii ‘Variegatum’ or it can be listed as var.
pluriflorum. These appear to be the same plant. In the Royal Horticultural
Society’s Plant Finder (a great source for tracking down names) there is no
thunbergii, only pluriflorum, so it appears to be one of those plants that
drift from one name to another for awhile before settling.
Several plants are either
quite similar in appearance or
near relatives of the Solomon’s Seal, and they all make fine companions. The
false Solomon’s Seal (Smilicina racemosa) is a Northwest native; its flowers
are a plume of creamy white. There is also evergreen Solomon’s Seal
(Disporopsis perneyi), twisted stalk (Streptopus amplexifolius) and fairy bells
(Disporum hookeri) (the latter being two more Northwest natives).
More species are being
introduced into the gardening world
all the time, thanks to intrepid modern-day plant hunters such as Dan Hinkley.
These may be harder to find in the trade, but sometimes the hunt is half the
Look for the diminutive groundcover P. hookeri that grows
to only three inches high, but spreads out in a carpet. Polygonatum humile is
slightly taller—to about six inches. These short species obviously don’t have
room to arch their stems as the taller species do. When in bloom, the upright
stems of P. humile look like they have a vertical white zipper of bells.
garden in spring catches at the heart strings.
Be sure your woodland garden includes Polygonatum for an effect that charms in
spring, but also carries through with stately elegance until the garden rests
for the year.