Going out on a limb….

My poor weeping cherry.

Last spring, my weeping cherry tree was a forty-foot display of dripping, sweet white cherry blossoms that put all other trees to shame.  I was extra thrilled, because it had lost a major branch back in the “Blizzard of ‘10” and it was so beautiful that I didn’t mind the prospect of its fruits relentlessly raining down on the patio, squishing purple smears on to bluestone and wicker. 

The fruits fell, annoying as always, but then the tree started to drop yellow leaves.  All over the lawn.   Little yellow leaves.  It looks like fall.  Being a person of fastidious Dutch descent, little yellow leaves littering my lawn and patio in the middle of summer drive me crazy.  It’s too messy! 

I did what any normal person would do.  Just after the Fourth of July, I called my arborist and had him test the tree.  The lab reported no condition that would explain this leaf loss. The arborist’s conclusion is that this 60 year old tree was too dry since there hadn’t been much rain.

I was puzzled.  My irrigation system was working.  In fact, the ground had been so soft and muddy, I’d concluded it had suffered from too much water.  I’d done what any normal person would do.  I’d turned the sprinkler system down, knowing that sprinkler systems are not necessarily designed for maintaining large trees and shrubs.  Indeed, running sprinklers superficially several times a week instead of thoroughly once a week can actually harm tree roots.  Tree roots, other than taproots, tend to grow in the top 6-36 inches of soil, the majority in the top twelve inches, so overwatering with an irrigation system can result in root rot just as under watering dries roots out.

Alarmed, I examined the trees in front of the house.  My straggly magnolias were also dropping leaves.  One was particularly stricken so I hand watered it, letting the water soak in long and deep.  Two feet from its trunk, I discovered a sprinkler head that had been buried by some long-departed, feckless landscaper who’d piled on successive layers of mulch without bothering to liberate the irrigation system.  The sprinkler head has since been repaired and the tree has been watered regularly.  Its leaves have stopped falling, and new growth has miraculously appeared.   The new growth may not have enough time to harden off before winter, but I'll worry about that later.

Street trees are often abused.

My street tree, on the other hand, a gorgeous Japanese zelkova (Zelkova serrata), was dry but I have been watering this puppy more properly since it isn’t covered by the irrigation system.  I feel a special affinity with street trees:  Theirs is a very stressful life.  For one thing, their root space is limited. Unlike trees that grow out in the field, their roots are hemmed in by concrete, asphalt, and who knows what underground obstacles so their roots can’t grow beyond their drip line as they otherwise would.  Think of them as urban bonsai trees. 

Adding insult to injury, the soil around them is inevitably trodden upon (and peed upon by dogs) so it gets very compacted and compacted soil doesn’t hold much oxygen, which roots need, nor does water penetrate it easily.  Many street trees also have plantings at their bases, which compete for the little water that they do get, or have too much soil and mulch piled on them.  I was horrified to learn that liriope, which is planted around the base of my zelkova, is especially bad since it forms thick mats that prevent water from getting to tree roots.  I will yank it when the P&O Street construction project is finished and the brick sidewalk has been repaired.  Better to disturb those poor roots only once.

A gator full of water.

Back to watering.   My street tree strategy is to leave my hose on low once a week or so, letting it soak the ground in the tree box.  It’s best to leave it running for about thirty minutes, which works well if, like some people, you lock yourself out of the house and have to find the spare key.   Smart people, like someone around the corner from me, wisely put an orange cone of some sort near the hose to warn hapless pedestrians not to trip.

All new trees need regular, thorough watering.  They should be watered deeply once a week for at least the first couple of years after installation to assure good root development.  Aside from hand watering, you can place a soaker hose around the base of a new tree and hook your hose up to it when you need to water.  Or you can get a reservoir device like an ooze tube, plastic saucer, or gator that slowly disperses water once it is filled.  I have a neighbor who is dutiful about filling the gators around the brand new street trees near his house, and I’d like to encourage everyone to water the nearest street tree as well, established or new.  I say this on behalf not only of all Georgetowners, but also on behalf of “Trees for Georgetown”, which annually does such a great job replacing dead and missing trees.

As for my weeping cherry tree, additional water and rainfall has not slowed the falling leaf problem.  I am going to do what any normal person would do.  I will seek a second opinion.

A pink robinia planted thanks to "Trees for Georgetown"

A Clean, Well-Whited Place *

I love the Fourth of July in our Nation’s Capitol.  This was my first in way too long.  Heat, humidity, fireflies, family, fireworks, and concerts in the park.  It was great but I’d forgotten how hot it can be until I went out for a nice, long walk.   As I sweatily criss-crossed streets in search of shade, my eyes were drawn to the soothing cool of every white flower and variegated leaf along the way, and  I was reminded of my front garden in Connecticut.  There, after spring’s riotous colors, my front garden always subsided into a calm green and white affair.

I miss this calm, cool refuge -- an elegant oasis of glacial whites and luscious cool greens contrasting with the heat of a summer day.

White trunked birches are stunning
against a dark green background.

Ever one for escapism, I began fantasizing about what I would plant if I had the discipline to create a white garden.  Discipline, I say, because a white garden obviously means the utter exclusion of colors other than white, green, and silver -- but maybe only for a season.  If you were clever, you would let the unruliness of colorful spring bulbs and perennials abound unrestrained, only to yield in summer to chilling whites before glorious oranges, yellows, and reds of fall set in.

It’s always best to start with the bones of a garden, so I’d start with crisply clipped dark evergreens – boxwood, yew or holly.  Then I’d incorporate birch trees, the white bark of which would look as lovely in winter as in summer.  Birches like their roots shaded and moist, so I’d plant them where the summer sun could not broil the soil beneath them.  As they aren’t known for their heat tolerance, the best choice for Georgetown is the Whitespire Birch (Betula platyphylla japonica 'Whitespire'), which is relatively heat-resistant.  Most white-trunked birches are susceptible to leaf miners and the bronze birch borer, so a program of inspection and treatment is essential.

Annabelle's sweet white umbels.

I’d have to have hydrangeas in my fantasy white garden, but which one? I adore oak leafed hydrangeas (Hydrangea quercifolia) with their exfoliating bark and strong dark red fall color, but their texture would be too woodlandy and coarse.  Instead, I’d choose the Annabelle hydrangea (Hydrangea arborescens “Annabelle”).  Annabelle is very well behaved in gardens, and unlike many hydrangeas, can be cut back severely in spring since she blooms on each year’s new growth.  I love her umbels of delicate white flowers, which start out vary from light chartreuse and to white, and I’d leave the tan-colored skeletal blooms in winter to contrast with the dark evergreen backdrop.

The green and white leaves of variegated vinca.

Beneath Annabelle and the birches, I’d plant variegated periwinkle (Vinca minor `Variegata`), which would bear blue flowers in early spring but would be perfect for the all-white summer garden. Planted in a shady spot, the white margins on its leaves would lend the illusion of dappling sunlight and offer a contrast to the darker leaves surrounding it.  

In a sunnier location near a wall, I’d pop in variegated Winter Creeper (Euonymous fortunei ‘Emerald Gaiety’).  Its small leaves are a mottled green and white, and its structure would serve as a shrubby groundcover, as well as a climber.  It would make its way up the wall, and in winter would be beautiful in snow while in summer it would serve as cool backdrop for everything else.  This euonymous is a tough little workhorse that does well in a variety of conditions and soils, and doesn’t have the powdery mildew problem that bedevils Manhattan euonymous. 

Naturally, my fantasy white garden would be incomplete without flowers.  I’d usher in summer in late May and early June with pure white bearded iris.  Their stiff, pointy leaves, a light green, would also provide great texture for the rest of the season.  The bearded iris might be followed with white lilies for fragrance, and white Echinacea for simplicity. 

White bearded iris stand out in an early June white garden and their foliage adds structure for the rest of the summer.

The whimsical plate-sized flower of rose mallow.

Surely I’d be tempted to be whimsical and plant the exotic, bold, pure white rose mallow (Hibiscus moscheutos) in the garden, just to make me laugh.  This hardy Southeastern native dies back to its roots each year, but that doesn’t stop it from growing 4-6 feet tall in summer and sporting flowers the size of dinner plates.  My friend, Anthony Archer-Wills, the British water gardener, planted them heavily in a wetland on which we collaborated, so I know it needs moist soil and full sun.  My preference would be the hybrid “Hibiscus x ‘Blue River II’”, a pure white bloomer that blooms all summer. 

This garden would be stunning on long hot summer days but since white gardens double as moon gardens I’d want to be sure my night lighting was perfect, too.  After all, it is my fantasy garden and money is no object! My pet peeve is up-lighting.  The last time I saw a natural light source emanating from the ground was -- never. Although garden lighting has its practical applications (safety, security, etc), your lighting should never look like you are aspiring to hold major league baseball night games in your back yard, or like the lighting around Ryker’s Island (unless you live with in-mates who threaten to break out and indulge in nocturnal mischief).  I will grudgingly agree that sometimes up-lighting can be attractive, but in general, the best lighting for gardens is LED lighting, discreetly hung from tree branches or buildings , and produce a soft light that replicates moonlight.  This would certainly be the best for the white garden at night.

Alas, the Fourth is over.  I’m back to reality…..but stay tuned for my next escape.

* With many thanks to Jane Makin for providing an excellent title.

When it rains it pours….

Sedum just starting to bloom.

I should have written this article weeks ago when, despite the daily promise of afternoon thunderstorms, everything was parched.  Maybe it was reading about the drought in China, but I was sure we were in for a long dry spell. A native of the Pacific Northwest, I can handle endless rain and fog, but not endless sunshine and lack of rain so I have developed tricks that I’m convinced induce rain and I started down the list.

I left cushions out when thunderclouds loomed, grabbed my sunglasses when I walked out the door, grabbed my umbrella for every outing, bought an extra length of hose, drenched my “street” tree, and watered my pots.  I stopped short of leaving the Mini’s sunroof open, however.  (That, sad to say, actually once produced a copious overnight downpour.) 

Nothing worked -- until I sat down to write about drought resistant plants. 

Foxgloves at their peak.  Let them natuarlize
by leaving them to go to seed.

Drought resistant or tolerant plants manage prolonged but not eternal dry periods.  Some, like sedum, are succulents and retain water.  Others are silver and reflect sunlight and some are pubescent (at last, a chance to use this word), meaning they are fuzzy.  The fuzz reduces air motion over the leaf, thus minimizing transpiration.  Some drought tolerant plants have waxy leaves that slow water loss, and others have taproots that store water.  The flip side is, that, these plants often do poorly if overwatered or if planted in heavy wet soil.  Sprinkler systems can play havoc with them.  And nothing is drought tolerant until it’s well established.

For dry shade, I like epimedium, Solomon’s seal, hellebores, and both the perennial and biennial forms of foxglove (Digitalis).  Biennial foxglove does well in shade and sun, and self-sows if permitted to “go to seed”.  It blooms every other year, so if you only plant them once, you will have blooms every other year.   Plant them two years successively to ensure annual blossoms.  Be wild and plant white ones one year and pink ones the next.

Thyme comes is a variety of colors, all gorgeous.

Lots of sun-loving plants tolerate dry weather well.  Thyme, for instance, which has petite leaves that limit transpiration, prefers to be dry.  Since it comes in solid green as well as variegated models, and both have gorgeous purple blooms, you can be quite creative with it:  I once saw a miniature knot garden planted with tightly clipped thyme.  Other herbs like sage, rosemary, and lavender are great for dry periods, though I will confess that I have killed more lavender than I’d like to admit, probably because I planted it in soil that didn’t drain very well.

Mullein is a stately plant that adds
dignity to any planting.

Lamb’s ear has sensuous silver pubescent leaves, and is an effective edging plant.  It’s texture and color work beautifully in borders with variegated, green leafed, and red leafed plants and needled shrubs.  If you are looking for accents, toss in mullein (verbascum).  Their broad leaves and tall spikes are dramatic and their tiny flowers are incongruently delicate. Day lilies are great and, like iris, will double as erosion control.  Don’t forget Black Eyed Susans (Rudebekia) and Cone Flowers (Echinacea) which have terrific winter structure, according to Dutch plantsman, Piet Oudolf, who also leaves the seed heads to attract birds.

Then there are annuals that are drought resistant and work well in pots, which dry out fast.  Waxy leafed ivy geraniums are reliable and they come in different colors.  So is lantana, which I especially like because of their citrus-ey fragrance, wide variety of colors, and loose structure.  Zinnias do very well in dry conditions, and, in fact, get unsightly powdery mildew if allowed to get too wet.

The fragrance of rugosa roses defines summer.

If you are looking for drought tolerant shrubs for a sunny spot, try rugosa roses.  I know they are a little informal and associated with the beach, but they can be stunning in formal urban settings, too, and their fragrance is to die for.  Best of all, they are repeat bloomers and when they finish, present lovely deep orange and red rosehips.  Cinquefoil (Potentilla fruticosa) is a great long blooming shrub with small white, light yellow, or dark yellow flowers, and you can try pepper bush (Clethra alnifolia) if you want to attract butterflies. 

The ancient Ginko's semi-circular leaves.

And yes, Virginia, here are drought tolerant trees.  One of my favorites is Gingko biloba, which is one of the oldest tree species in existence.  Gingkoes,s great street trees, are dioecious.  The females bear fruits that are smelly when they fall and very tasty when they are served.  Their oddly shaped leaves turn golden yellow in fall. For large gardens I like Golden Rain Tree, (Koelreuteria paniculata), which is blooming now.  It’s long-lasting panicles of small yellow flowers turn into lovely brown pods in late summer, offering another interesting texture in the garden.  Happily, you can rely on crabapples to be drought resistant as well as the fine-leafed Japanese Zelkova (Zelkova serrata), which has a great dark reddish fall color.  These are gorgeous upright, vase-shaped trees that get quite large and were introduced as substitutes for American Elms after Dutch Elm disease decimated them.

  Mulch your plants (but never let me catch you using unsightly wood chips, bark nuggets, or dyed shredded plywood).  And, if you have an irrigation system, think twice about planting what needs little water.  Finally, just because a plant can tolerate drought doesn’t mean it never needs water.

If we are threatened by another dry spell, expect a sequel to this article.   There are many more drought tolerant plants to write about and this may be my latest trick to make it to rain.  

Koelreuteria  provides long-lived summer interest

I never promised you a rose garden…

No flower is more romantic than a rose.  I love iris, orchids and lilies of the valley -- just about anything that blooms, but roses, cultivated for over 5,000 years, are in a class of their own. Having a very shady garden, and therefore being unable to grow roses, and wanting to enjoy someone else’s hard work, (oh, the pruning, the watering, the deadheading!) I wandered up to Tudor Place a few weeks ago in search of roses and a bit of borrowed romance. 

The Four-Seasons Rose.

Roses are among the original ornamental plants that were planted at Tudor Place, where Martha Custis Peter, Martha Washington’s granddaughter and the mansion’s first occupant, planted them in 1815, near the end of the War of 1812.  She must have done so just as the house, designed for her and her husband by William Thornton, the architect of the Capitol was nearing completion. 

Old Monthly attracts a bee.

Two of her favorites are still grown there.  One of them is a charmer called “Four Seasons Rose”, (Rosa damascena ‘Bifera’), which has purportedly been in cultivation for a millennium.  Its flexible, upright stems bear soft, light pink ruffled roses all summer.  She also loved “Old Monthly” or “Old Blush” (Rosa chinensis “Old Blush), which was brought from China to the West in 1752.  It is upright as well, and can be grown as a climber.  At Tudor Place it grows in full sun on the south side of the house where it thrives next to the “Four Seasons Rose” bearing medium pink blossoms all summer long.  Perhaps it’s the romantic in me that likes to think of the first First Lady’s granddaughter taking cuttings from the roses at Mount Vernon where she was born, and planting them at her new home in Georgetown.  The “Old Blush” shrubs currently growing at Tudor Place are very likely cuttings of the ones Martha Custis Peter herself planted!

The knot garden at Tudor Place as restored by Armistead Peter III.
The newly restored grape arbor is to the right.

Her descendents also planted roses, most notably in the knot garden that lies to the north of the house.  It dates to the early 1800’s and was originally planted with herbs near the Round Garden where the Peter family grew vegetables.  The original knot garden was decimated in the late 1850’s by neighbors who poached its boxwood hedges for Christmas greens while Britannia Peter, then owner of Tudor Place, was away.  When Britannia returned in 1862, she replaced the knot garden with grass, and had most of the boxwoods moved to the lower walk, where some of them survive. 

That was the end of the knot garden, the layout of which was forgotten, until Britannia’s grandson and great grandson serendipitously found a copy of the plan in a book published by the Virginia Garden Club.  The book described a number of gardens, including one belonging to a Peter cousin who’d replicated the Tudor Place knot many years before at Avenel, her estate.  Delighted with the discovery, Armistead Peter III, Tudor Place’s final owner, persuaded his father to take cuttings of the original boxwoods and, using the newly minted shrubs, recreated the original knot garden, with a few adjustments, and planted roses in it, rather than herbs.

Gruss an Aachen blooming at the center of the knot garden.

Peter, in his writings about the garden, tenderly remembers his late wife, picking and arranging roses in the house, and that she had been especially fond of “Gruss an Aachen”, which he had planted in the triangles around the center of the knot (talk about romantic!).  It is easy to imagine it being a favorite, since this rose, introduced in 1909, grows to about 3 feet tall and its orange-pink buds yield a flower that opens to a light pink and fades to creamy white.

In addition to “Gruss an Aachen, there are the five petalled dog roses (rosa canina), the hips of which are high in vitamin C and antioxidants, and are used to make tea, wine, and marmalade.  It only blooms once a season on its sprawling stems.  Nearby is the Mary Rose, one of my favorites, and not just because I managed to keep one alive for ten years.  A David Austin rose introduced in 1983, it is an old fashioned looking pink rose that blooms in clusters.  Mary Roses are wonderfully fragrant and will rebloom if they are deadheaded. 

A full blown Mary Rose.

Close to the knot garden is the newly rebuilt grape arbor.  The old one had been covered with grapes, as well as the very robust New Dawn rose, a sweet faintly pink climbing rose, which is very easy to grow.  My test for “easy”?  If I can grow it, anyone can, and I can grow New Dawn.  The old ones here were diseased and have been replaced with new plants that will bloom lustily in the years to come.  New Dawn re-blooms, if deadheaded, though its summer blooms are less prolific than its first bold display.

Zephrine Drouhin is the rare rose
that can take some shade.

A Tudor Place climber that I am dying to try is the exotically named Bourbon rose, “Zephrine Drouhin”, introduced in 1868.  Silly me, I always thought Bourbon roses were named for the 

Bourbon monarchs, but in fact, they are named after the island (Ile Bourbon, now renamed Reunion) in the Indian Ocean from whence they come.  “Zephrine Drouhin” has a voluptuous deep pink flower that grows on nearly thornless stems and reputedly blooms well in shade, the only rose to do so, heavily in the spring with a second flush of flowers in autumn.  What makes it almost irresistible to me is that the BBC Gardener’sWorld.com considers them fit for a beginner.  I’m checking the catalogues now.

Many, though not all, of the roses at Tudor Place are past their season’s prime now, but it is still worth a visit to see the repeat bloomers, not to mention the rest of the garden.  Happily, the roses will be back in force next May, romance and all!

Going Native

Going Native

Lady Slipper in bloom in Maine.

Crossing the bridge into Maine at dusk last Friday, as the mist inevitably closed in, it was possible to discern that spring has only just arrived in southern Maine.  Saturday morning when the daylight penetrated the fog shrouding Pemaquid Point I could see that the daffodils have yet to “peak” and the lady slippers have yet to bloom.  Lupines are still a month away. 

Admiring the spring flowers in the country gardens along the way to the Cupboard Café which serves the world’s best breakfast sandwiches and the world’s most fantastic sticky buns (http://www.thecupboardcafe.com/ ) I was reminded of the conclusion I draw every spring: Magnolias, Kwanzan cherry trees, and other non-native trees and shrubs look very out of place here, while the natives look quite at home. 

I felt a pang of conscience as I considered this.  I have been writing about so many non-native plants lately that, to justify myself, I tried to believe that the obverse is true back home and that native trees and shrubs don’t look as comfortable in urban gardens as they do in the country.  That, however, is bunk.  In reality, most natives look great in Georgetown. 

Amelachier blooming next to the Potomac.

Take, for example, amelanchier canadensis, a native from Maine through the Carolinas.  It is now at its peak Downeast, but in DC it blooms in early April.   Its common names, shadblow or serviceberry, reflect the timing of its blossoms – when the shad runs and when, in the “olden days”, the traveling parson could reach remote towns after the snows had melted and the mud had subsided to perform the services of marriage, baptism, and funeral.   I love its delicate flowers, which appear just before the bronze tinged foliage emerges, as well as its lovely gold and orange autumn color.  In August, birds eat the dark blue berries that their human competitors use in jellies, pies, and pemmican.   Emphasizing the important role native plants play in our ecosystem, amelanchiers are a larval food for the red-spotted purple butterfly, which strangely enough, is actually black and blue!   These are great specimen trees and there are several cultivars from which to choose.

A native dogwood in full bloom.

Another excellent tree that is a larval food source for butterflies (this time the sweet blue “spring azure butterfly”) is our own native dogwood, cornus florida.  I have never subscribed to the belief that native dogwoods are too susceptible to disease to be reliable – that claim seems a ploy to sell hybrids and Korean dogwoods.  Native dogwoods just need to be planted well in moist, rich soil.   Ranging from light to dark pink and creamy white, dogwoods are the perfect small-garden tree not only for its spring glory but for its voluptuous red berries in fall which are devoured by birds, its purplish red fall color, and its dark craggy bark which looks dramatic against a frost-tinged backdrop.  Amazingly, what we think of as petals are really colored leaves called “bracts” that attract pollinating insects like bees to the tiny yellow flowers at their centers.    I love knowing that this American tree was introduced to England in the second decade of the 1700’s.

The pea-shaped flowers of the native redbud.

Blooming in late April coincidentally with dogwoods is the redbud, (cercis canadensis), a tree purported to be a favorite of George Washington’s, who had them planted in abundance at Mount Vernon.   If you have never seen dogwoods and redbuds blooming simultaneously along the Skyline drive, make your plans for next spring now.  It is breathtaking.  Redbuds are in the pea family and their little pea-like flowers cling to dark branches before the emergence of leaves.  The flowers, ranging from lavender to purple to white depending on the cultivar, are purportedly edible if you like that sort of thing (edible flowers make me squeamish) and are an important nectar source for honey bees while cardinals are among the birds that dine on the seeds.  As I toy with the notion of planting a non-native Japanese maple for its dark  red foliage, I quickly remind myself that one of my favorite redbud cultivars is “Forest Pansy”.  Its leaves are a dark purple-ish red and look stunning all summer long if planted in a good deal of sun -- like Japanese maples, the leaves become greener in shade. 

Halesia blooming the woods beside the C&O Canal.

Silverbells or snowbells (halisia) are little-known trees that bloom just about the same time as amelanchiers.  They are uncommon, perhaps because they are a bit fussy if not planted in part shade and in moist but well-drained acidic soil.  They have delicate white flowers, though there are pink-flowering cultivars, which hang pendulously from their branches just as the spring-green foliage emerges.  True, the leaves are not very colorful in fall, but the nectar of its beautiful flowers is very important to bees – did you now there are over 700 native species of bees?  Interestingly enough, halisias are named for Dr Stephen Hales (1677-1761), the first man to measure blood pressure in horses and sap pressure in trees.

Fringe Tree's flowers are as fragrant as they
are beautiful.

And then there is the amazing fringe tree (chionanthus virginicus), which has just finished blooming in Georgetown.  This fragrant American native is in the olive family and was used medicinally for a number of ailments ranging from jaundice to dyspepsia.  It is a relatively slow growing tree or shrub that leafs out late and has a subtle golden fall color.  Like gingko trees and hollies, fringe trees are dioecious (yes, this will be on the exam) which means they are either female or male.  While the males tend to have the showier flowers only the females bear the bluish olive-shaped drupes beloved by birds.  It is often impossible to know what gender the bushes are when purchased, but if it has drupes, you know it’s a girl.  It was surely the fringe tree’s delicate beauty and fragrance that compelled Thomas Jefferson to ask a botanist friend in Philadelphia to send him chionanthus seeds while he was living in Paris in 1786, so he could grow them there.  They are notoriously slow growing, though, so it probably took his seedlings years to bloom.

So what is the big deal about native plants?  Aside from their beauty, they provide food and shelter for birds, butterflies, and our dwindling populations of bees.  They tend to require less watering, fertilizer, and pest control because they are already adapted to our environment, and if they self-sow they are not considered detrimentally invasive like English ivy, Norway maples, and barberry are.   I am no purist but there is a lot of sense in using what naturally occurs in our area, especially when it comes to the role native plants play in supporting wildlife.   There are many sources of information about using and procuring natives, from books to magazines, and a variety of websites.  A great place to start is a Washington State-based website ( http://www.plantnative.org/ ), which has information by state and region on plants and nurseries.  Go native!