Plant Reference I--O
Ilex opaca
American Holly
Ilex verticillata
Winterberry
Iris 'Black Gamecock'
'Black Gamecock' Louisiana Iris
Iris cristata
Dwarf Crested Iris
N. America, z. 4-9. An exquisite native Iris, only 4" to 8" tall, with typical Iris foliage that spreads slowly to form a
solid mat and charming blue-violet flowers carried above the foliage in mid-spring. As tough as it's beautiful, it will tolerate
sun or shade, moist or dry soil.
Iris cristata 'Alba'
'Alba' Dwarf Crested Iris
N. America, z. 4-9. A vigorous form of this beautiful native with pure white, gold-crested flowers in mid-spring. Spreads
relatively quickly into a dense carpet only a few inches high.
Iris cristata 'Powder Blue Giant'
Dwarf Crested Iris
N. America, z. 4-9. This unusual and beautiful Crested Iris selection is indeed a soft blue-gray, with deep blue and white
markings and gold crests. And it's big for the species: up to 10" tall with 3 1/2" flowers in spring. Sited in partial shade
and humus-enriched soil it will spread fairly rapidly to form thick, ground-covering mats. Spectacular!
Iris fulva
Copper Iris
N. America, z. 5-10. The term "copper" doesn't convey the complex mix of wine red, deep violet, and gold in the unusual flowers
of this southeastern Iris. The flowers appear in late spring, several to a stalk, and are borne well above the slender, 3'-4'
leaves. This is a very interesting plant for moist to wet soil in sun or part shade, and excellent with ornamental grasses.
Iris pseudacorus
Yellow Flag
Europe, z. 5-10. A vigorous Iris with handsome 1'-4' spears of foliage and large, bright yellow flowers in early summer.
Its robust clumps provide a boldly architectural accent for a sunny, damp spot or a shallow pool, but it's also quite happy
in average garden soil in sun or a little shade. Not recommended for naturalizing since it spreads readily.
Iris tectorum
Roof Iris
China, z. 4-10. A lovely, late-spring blooming Iris with wide fans of pale green leaves and large, rather flat, frilled flowers
in shades of soft blue. A low-growing Iris, only 12”-16” tall, it will nonetheless form large clumps at the front of a border,
and can also be naturalized in sun or part shade and average to moist soil. Tough as nails, but much prettier!
Iris tectorum 'Alba'
Roof Iris
China, z. 4-10. A pure white Roof Iris with a gold-marked crest, less commonly seen than the blue form but equally lovely
and just as tough. Roof Iris is surprisingly drought tolerant.
Iris versicolor
Blue Flag
Itea virginica
Virginia Sweetspire
N. America, z. 5-9. A 3'-5' mounding, colonizing Eastern shrub with arching stems and glossy leaves that persist well into
winter. In early summer it bears cascades of scented, white bottlebrush flowers, very attractive to butterflies. Fall foliage
color is highly variable and generally spectacular. An easy, very nice shrub for sun to part shade, wet to dryish soil.
Jeffersonia diphylla
Twinleaf
N. America, z. 4-9. The leaves are the thing with Twinleaf. Although it produces pleasant, fleeting white flowers in early
spring, its real attraction is the unusual leaves, each cleft almost in two and borne on its own wiry stem. A mature clump
looks like a flight of green butterflies with maroon edges to their wings. Enchanting! The seedpods are also unusual: miniature
canisters with pop-top lids. A lovely plant in colonies in a partly to fully shady spot with moist soil.
Juncus effusus
Soft Rush
Cosmopolitan, z. 4-9. Regionally common but often unnoticed in the wild, Soft Rush can be striking in cultivation. Its glossy,
grasslike stems form a dense evergreen mound 2'-3' high. Upright at first, the stems may arch with the weight of showy brown
flower heads to cover an area wider than their height. Suited to constantly damp soil or shallow water in sun or part shade,
it makes a bold accent plant for pond, streamside, or any damp area.
Juniperus virginiana
Eastern Red Cedar
Kalmia latifolia
Mountain Laurel
N. America, z. 5-9. Mountain Laurel is one of our most beautiful native shrubs, with glossy, evergreen foliage, a distinctive,
mounding growth habit, and spring clusters of pink-budded flowers that open white. It is, however, specific in its requirements:
acid, organic, freely draining soil and some protection from blazing sun and winter wind. It will grow and bloom in woodland
shade, but will bloom more heavily at woods' edge or on the north side of a house. Slow growing and very long-lived, it is
a prime choice for any spot where conditions suit it.
Kirengeshoma palmata
Yellow Wax-bells
Japan, z. 5-8. An elegant oriental perennial, 3'-4' tall and eventually as wide, the mature leaves of Kirengeshoma are nearly
round, palmately lobed, and a lovely pale green. The soft yellow flowers open in late summer in loose clusters carried well
above the leaves on slender stems. An exotic, beautiful specimen for moist, acid soil in partial shade.
Kosteletzkya virginica
Seashore Mallow
N. America, z. 6-10. The only difficulty with Seashore Mallow is spelling its scientific name; apart from that it's a charmer.
A relative of the Mallows (Hibiscus spp.), it is a tall—to 5'—airy plant which in late summer produces many 2" pink or occasionally
white flowers with prominent, bright yellow stamens. Occurring naturally along beaches and marsh edges, it is a good waterfront
or rain garden plant, but is also quite at home in average garden soil in sun.
Liatris spicata
Gayfeather, Blazingstar
N. America, z. 3-9. A showy native with a basal tuft of narrow leaves and strong 2'-3' stems densely packed with feathery,
rose-purple flowers in mid-summer. A good garden plant and popular as a cut flower, Gayfeather prefers full sun and average
to moist soil.
Lilium canadense
Canada Lily
N. America, z. 3-8. This exquisite and rarely available native grows to 3' or more, with a single slender stem surrounded
by whorls of dark green leaves. The stem provides a standard for a spectacular summer display of yellow to red-orange, pendant
bells with flared petals—looks like something that should be carried aloft in an exotic ceremony. Canada Lily requires consistantly
moist, acid soil, sun to part shade, and may need protection from deer and voles. Order early for spring shipment, since
by late spring it is too tall and slender to ship without breakage. It can also be shipped as a dormant bulb in the fall.
Lilium superbum
Turk's Cap Lily
N. America, z. 4-9. The commonest wild Lily in Maryland—if any can be called common these days—is this magnificent plant.
Usually found near water, a mature bulb produces 5'-6' stalks bearing a dozen or more large flowers whose strongly reflexed
petals range from orange to cinnabar red with a yellow throat and maroon spots. Definitely a showstopper. Although they
take time to mature they will thrive and spread in moist to wet soil in full sun to part shade. As with L. canadense they
should be ordered early, or in the fall.
Lindera benzoin
Spicebush
N. America, z. 5-9. A fine woodland shrub, 5'-12', with an open, spreading habit. One of our earliest spring bloomers, it
bears many clusters of tiny, greenish-yellow flowers, lighting up the gray-brown of the woodlands. In fall it bears oval scarlet
berries which birds feed on and its foliage turns an exceptionally clear yellow even in deep shade. A host plant for the Spicebush
Swallowtail butterfly, its name comes from its strongly aromatic twigs, leaves, and berries, which give off a tangy, lemony
scent when crushed. Likes moist soil in partial to full shade—best fruiting with some sun.
Lobelia cardinalis
Cardinal Flower
N. America, z. 4-8. Slender 2'-4' spires of intensely scarlet flowers in late summer—one of the brightest reds in nature,
and beautifully contrasted by the deep green leaves. Requires moist to wet soil with high organic content, but will bloom
in full sun to full shade. A great favorite of hummingbirds.
Lobelia siphilitica
Great Lobelia
N. America, z. 4-8. Similar in form to Cardinal Flower but a stouter, larger-leaved plant, with spikes of clear blue flowers
in late summer. Sun to partial shade in moist/wet soil. Popular with bees and butterflies and an excellent, long-lasting
cut flower.
Lonicera sempervirens
Trumpet Honeysuckle
N. America, z. 4-9. A woody vine growing up to 15' with support, Trumpet Honeysuckle produces clusters of orange to red flowers
whose narrow trumpets seems specifically designed for hummingbirds, who love them. It tolerates part shade but blooms better
and longer in full sun, and is an excellent choice for growing up a trellis or over an arch. It has no scent, but is otherwise
a much showier and much better behaved vine than the pestiferous Japanese Honeysuckle (L. japonica).
Lonicera sempervirens 'John Clayton'
'John Clayton' Trumpet Honeysuckle
N. America, z. 4-9. Trumpet Honeysuckle is normally coral red, but the blooms of 'John Clayton' are a rich apricot. Otherwise
it's the same fine woody vine, growing to 15' with support and delighting hummingbirds—and gardeners. Sun to part shade and
average soil.
Lychnis coronaria
Rose Campion
Africa, Eurasia, z. 3-9. An old-fashioned garden plant with wooly silver-green rosettes and very vivid magenta flowers for
a long period in mid-summer. Striking yet not too difficult to combine with other colors of the season, and a prime choice
for poor, sandy soil in full sun. A short-lived perennial, but it self-seeds readily.
Lychnis x arkwrightii 'Vesuvius'
'Vesuvius' Arkwright's Lychnis
Garden hybrid, z. 5-9. A very nice hybrid of an old standby, maltese cross (L. chalcedonica), 'Vesuvius' has dark, bronzy
foliage 12"-18" high, topped by brilliant 2" flowers of an unusual burnt orange shade in early summer. Great accent plant.
Likes sun to partial shade, average soil.
Lychnis yunnanensis
Yunnan Catchfly
China, z. 4-8. In late spring this little Catchfly's basal tuft of narrow, pointed leaves sends up slender wands of cheerful
pink flowers. Only 6"- 12" tall and widely adaptable, it's a nice plant for rock gardens, pots, or any situation with full
to part sun and well-drained soil. A good substitute for Dianthus in humid climates.
Lycopus virginicus
Virginia Bugleweed
N. America, z. 4-9. The wide-spread but little-known Va. Bugleweed is a 1'- 30" tall plant with toothed, matte-green leaves
washed with purple—the more acid the soil the more purple the leaves, I suspect. Its flowers are insignificant but the foliage
makes it a desirable groundcover or filler plant in moist/wet soil in sun or shade, and a good choice near water and in rain
gardens. It can spread by seed or runners but is not aggressive.
Lysimachia ciliata
Fringed Loosestrife
. N. America, z. 3-10. A 2'-3' native with paired leaves and 1" yellow flowers with slightly fringed edges in summer, it
is more refined and somewhat less aggressive than the better-known L. punctata. Happy in sun or shade, average to dry soil,
it is excellent in a wildflower meadow or naturalized as a groundcover, and a good filler plant in the border.
Lysimachia ciliata 'Purpurea'
Purple-leaved Loosestrife
N. America, z. 3-10. The spring growth of this 2'-4' form of Fringed Loosestrife is lush and deepest red-violet, almost black—striking!
The color holds well in sun but tends to turn bronzy in shade; still, enough remains to enhance the yellow midsummer flowers
nicely. A robust grower for average to moist soil in sun or shade. Gorgeous with the sun shining through its leaves.
Lysimachia punctata
Yellow Loosestrife
Europe, z. 4-9. A larger and very showy loosestrife with deep yellow flowers in whorls around 4' stems. Often used for naturalizing
in a damp, sunny site, where it will make a great splash of color, it tolerates much drier soils with some shade. A tough
and dependable plant, but can be invasive.
Maianthemum (Smilacina) racemosum
False Solomon's Seal
N. America, z. 3-9. A very desirable woodland native better known to British gardeners, which shouldn't be the case. Smilacina's
creeping rootstock puts up graceful 1'-3' stems clothed in neatly alternating spear-shaped leaves. In spring the stems are
tipped with a plume of creamy white flowers, followed by showy clusters of berries speckled with purple all summer before
turning translucent red in late fall. A slow spreader once established, it likes part shade and moist, humusy soil; tolerates
dry shade.
Meehania cordata
Meehan's Mint
N. America, z. 4-8. A charming though little known mid-Atlantic native, Meehan's Mint is a deciduous, creeping groundcover
with small leaves, heart-shaped and softly hairy , and quantities of surprisingly large, lavender , snapdragon-like flowers
in mid-spring. It likes moist, humusy soil in part to full shade and deserves to be better known.
Mertensia virginica
Virginia Bluebells
N. America, z. 3-8. One of our most beautiful woodland natives, Mertensia's plum-purple shoots push up in earliest spring,
expanding into glaucous leaves of a peculiar smoothness—like a baby's skin. The 1" flowers hang bell-like from nodding stalks
and are pink in bud, becoming a very pure sky blue as they open. A marvelous if short-lived display: by early summer the plants
go dormant and disappear until the following spring. Mertensia prefers a moist, humus-rich soil in partial to full shade.
Mitchella repens
Partridgeberry
N. America, z. 3-8. An exquisite little creeper with rounded glossy leaves, pairs of tiny white flowers in late spring, and
bright red berries in the fall. The creeping stems cling closely to the ground and one plant will slowly carpet a 1'-wide
area. A beautifully textured plant, excellent with ferns, and a good rock garden or trough plant. Likes a well-drained soil
in partial/full shade; tolerates dry shade.
Monarda bradburiana
Bradbury's Bee Balm
N. America, z. 4-9. This Midwestern Bee Balm is far less well known than common Beebalm (M. didyma) or Wild Bergamot (M. fistulosa),
but has the advantage of being a smaller plant, only 1'-2', with shiny, dark green leaves said to be mildew-resistant—I'm
reserving judgment—and pale pink flowers. It also blooms in late spring, weeks earlier than its cousins. Moist to well drained
soil in sun or part shade.
Monarda didyma
Bee Balm, Oswego Tea
N. America, z. 4-10. A vigorous and very striking mid-summer bloomer, 2'-4' in height, with gorgeously scented leaves and
raggedy flowers of bright crimson magenta. Hummingbirds come and sit on them and simply refuse to leave. Likes moist soil
and full sun to partial shade. Good for border use and for naturalizing, spreads by runners.
Monarda didyma 'Jacob Cline'
'Jacob Cline' Bee Balm
N. America, z. 3-9. A strong-growing, true red—no hint of magenta—form of this popular native and hummingbird favorite, 'Jacob
Cline' will reach 4' and spread rapidly in moist soil, sun to shade. I find its reputed mildew tolerance to be over-rated,
but it's a good plant.
Monarda fistulosa
Wild Bergamot
N. America, z. 3-10. Very similar to Beebalm (M. didyma), but a little shorter—to 3'—and with more pink-purple in the flower
color. The major difference is that it's a plant of fields and wood edges and a better choice for dryish soil in full sun
than M. didyma. Equally aromatic and popular with hummers.
Morella (Myrica) cerifera
Wax-myrtle, Southern Bayberry
N. America, z. 7-9. A large—10'-15'—finely textured shrub with glossy, olive-green leaves that are evergreen down to about
0°. The leaves are aromatic, as are the small, frosted blue berries which birds favor. An excellent landscape plant which
can be pruned as a hedge or limbed up to make a small tree if desired, it adapts to wet or dry soils, prefers sun but tolerates
part shade, and is very salt tolerant. It is also very resistant to deer browsing. Plant several for best fruiting.
Oenothera missouriensis
Missouri Primrose
N. America, z. 4-10. Not a true primrose (Primula spp.), but a sun-loving, vigorous native with dark green, sprawling foliage
to 15" and very large, lemon-yellow flowers opening on summer afternoons and remaining to the next morning. Easy in average/dry
garden soil or naturalized in a sunny spot.
Oenothera speciosa
Showy Primrose
N. America, z. 5-10. Not a primrose and it doesn't look like one, but it's certainly showy. This southeastern native produces
2" open-faced flowers of soft pink fading to white at the center, veined with deeper pink, over a long period in summer. It
tends to sprawl and can be an aggressive spreader, although I don't find it so in my clay soil, but a clump in bloom is truly
spectacular. Prefers full sun and dry, sandy soil, but tolerates most anything.
Onoclea sensibilis
Sensitive Fern
N. America, z. 2-9. A rather tropical-looking fern with boldly cut, light green fronds to 2' in height. The spore capsules
are borne on separate stalks and look like clusters of little brown beads; they look interesting all winter in the garden
and are very good for dried arrangements. Sensitive fern is a spreader and a good deciduous groundcover for moist to very
damp soil in partial to full shade; also good under bare-legged shrubs.
Opuntia humifusa
Pricklypear Cactus
N. America, z. 5-10. An east coast native cactus with flat pads and large yellow flowers in mid-summer, followed by reddish,
edible fruits. Height usually less than l', but an established clump may be several feet across. Valuable as a groundcover
in sandy, dry soil—including beach sand—in sun or partial shade. Try it combined with Yucca filamentosa in a hot corner. Care
must be taken in handling because of fine spines.
Osmorhiza longistylis
Aniseroot
N. America, z. 4-8. This East Coast member of the carrot family also has a large root, which smells and tastes pleasantly
of anise and supposedly can be used for flavoring. An 18"-2' spring-blooming woodland plant, its clusters of tiny white flowers
are of less interest than its ferny, deep bronze-green foliage, which arises in earliest spring or even midwinter. Cut back
after flowering if you don't want it to seed about and to encourage new foliage. It may go dormant in midsummer if it dries
out. Partial/full shade, moist soil.
Oxalis violacea
Violet Wood-sorrel
N. America, z. 5-9. Violet Wood-sorrel's cheerful flowers, more pink than violet, pop up lavishly through its 1' mounds of
bright green "shamrock" leaves. Blooming in late spring/early summer, it's a good edging, rock garden, or pot plant. It's
also one of the very few natives I know that's quite happy indoors, and will bloom all winter in a sunny window. Its small
bulbs occasionally go dormant but resprout quickly, and if not confined to a pot may spread. Sun to part shade, average
soil.