Monday, March 31, 2014

Wings in the Garden


In the 1980’s when butterfly gardening was all the rage, I just had to have one of my own, starting with a small fenced area planted with all sorts of “butterfly” plants to attract them to this little spot where I could, in my fantasies, sit on a garden bench among the fragrant herbs and watch clouds of nectar-sipping beauties flitting about. Ha. Didn’t take me long to come to my senses and realize that you can’t corral butterflies like horses; what was I thinking? I needed to find out more about those winged gypsies of the insect world. A couple of reference books soon grew to a library of a dozen or more, and I began to think I might be an expert on butterflies and moths. But then reality set in and I realized that though my books had a lot to say about the adults, there wasn’t much about caterpillars. We can’t have butterflies if we don’t take care of their babies, but it seemed very little was known about all the life stages of Lepidoptera, from egg to larval stage, various instars, food plants, how and when they hibernated, hatched, and often, even what metamorphs into what? Then, in 2005, a book was published by Princeton University Press; “Caterpillars of Eastern North America” by David L. Wagner, and I started to really learn about the diversity of those insects, their lifestyles and plants they need to live. An estimated 8,000 moth and 700 butterfly species are found in North America alone, with nearly 200,00 worldwide. That is a lot of caterpillars. More are identified each year, and as comprehensive as this book is, even I find an occasional one that is not listed in it. I can only compare with different families and try to guess where in which one they belong. I find them totally fascinating; the diversity of caterpillars and their phenomenal survival tactics is mind-boggling.
The buzz these days is about saving the beautiful, beloved, familiar black and orange monarchs, but there are many more endangered butterflies that need our concern. Tiger swallowtails are the first butterflies we see here in early spring. The chrysalises overwinter in leaf litter (one good reason to not keep a too-tidy garden in the fall) and hatch out with the warming spring sun, just in time for lunaria (aka money plant) to bloom in the awakening garden, providing them with much-needed nectar when there are not many other flowers.  
 









Luna moth, just hatched. Its tails are not yet completely dry and extended.

The number of plants needed to sustain a butterfly and moth population is astounding. We all know that monarchs need the asclepias family, including milkweed, but many other butterflies also have specific requirements for life. Great spangled fritillaries visit milkweed for nectar too, but the caterpillars, which overwinter and become active in spring, must have violet leaves to eat; if there are none available, they will starve and die. (Not a problem here with native violets everywhere.) Beautiful luna moth caterpillars subsist on tulip tree (lirodendron) leaves. The carrot family is host for giant swallowtail caterpillars. We’ve learned to live with holes in leaves; helping sustain pollinators and beautiful insects is one of the best parts of being a gardener.
 

Pipevine swallowtail caterpillars

Planting a few nectar-rich flowers for butterflies and other pollinators is not nearly enough to make a good butterfly garden. There also has to be a wide range of plants for caterpillars to eat: no caterpillars, no butterflies. Here at Chaos we grow fennel, dill and parsley for swallowtails, to suppliment Queen Anne's lace and wild parsnip growing wild Out Beyond. 
 Some years ago when I planted native Dutchman’s pipevine, hoping to attract pipevine swallowtails, I didn’t realize how invasive that plant is—but, now, when it literally swarms with swallowtail caterpillars each year, I can’t get rid of it. I just deal with underground runners that pop up everywhere.  
Spicebush swallowtail caterpillar
 
Bad-tasting plants like these are swallowtails’ defenses, making them unpalatable to birds. Snake-mimic spicebush cats that munch spicebush and sassafrass leaves, start out looking like bird droppings, and with several instar changes, become orange and finally green with "snake eyes"; rolling themselves up in leaves so only the snake markings show to predators.  Some caterpillars rely on camouflage. I accidently put my hand on an oak moth caterpillar last summer; and even knowing it was there, its coloration was so close to the tree bark that it took several minutes to see it. Many caterpillars have stinging hairs, some squirt chemicals, and a few actually squeal and bite at predators. 
Oak moth caterpillar, camouflaged against the bark of an oak tree.
Here, most spring clean up is limited to paths and patios, leaving the majority of fallen leaves on beds, so overwintering caterpillars aren’t harmed. Luna moth cocoons are in leaf litter under the trees, hatching out in April, so I must wait to tidy up beds in the woods, or not. By that time most plants are big enough to hide the leaves anyway. Other pollinators live under there as well; plus carnivorous beetles, their larvae, and spiders that feed on harmful insects, making me careful about cultivating around plants so I don’t kill, for example, slug-eating firefly larvae.

I know; all caterpillars are not welcome in a garden. A single giant hornworm can nearly consume a tomato plant in one night, causing gardeners to curse loudly and crush it immediately. But not all hornworms eat tomatoes. There are some 70 species, many of which are plant specific, so randomly killing any you see would deprive us of many hawk and hummingbird moths that are so entertaining in the evenings. Introduced species like gypsy moths, bagworms, tent caterpillars, cabbage butterflies and cutworms wreak havoc in gardens, needing to be dealt with if we are to have vegetables to eat. We don’t use insecticides, instead relying on timing, floating row covers, plant collars, and natural predators. One alternative is bacillus thuringiensis, or BT, a natural biological control that is effectively used on larva of many kinds in certain situations. But it does destroy caterpillars, so apply with caution and only if necessary. BT can be found at any garden center. A must read for further information: http://www.ext.colostate.edu/pubs/insect/05556.html  

For nectar, butterflies need cluster type flowers with flat surfaces for landing pads, such as sedums, milkweeds, salvias, verbenas, zinnias, clover, lilacs, et al. They also like a good mud puddle for salt that is necessary in mating, especially if it has rotten bananas, molasses, or sponges soaked in fruit juices and stale beer in it. A wide saucer or birdbath makes a good feeder. They are also attracted to carrion, dung piles, and sweaty people. If you are blessed by butterflies landing on you, they are probably licking up your salt.  
 

 
 
 
 
 
 
 
 
A little Melissa butterfly, tasting my finger
Moths prefer tubular flowers, especially night-scented ones like lilies, hostas, nicotiana, daturas, phlox, and have even been known to visit hummingbird feeders.  
Cecropia moth, one of our largesty silkmoths, seems to be declining because of parasitism by a tachinid fly that was introduced to control the gypsy moth, an invasive species from Europe that is devastating North American forests. Another example of many well-intentioned attempts to correct a problem has gone awry. Now, how far must we go to control the tachinid fly? And then, what?
All of these plants also attract many other pollinators, providing food for a wide range of insects which are not only vitally necessary to keep our plant world humming along, they are also important members of the food chain for both birds and mammals. Many are the staple foods in the diets of forest-nesting birds.

Besides my caterpillar book, my other favorite reference is a small, information-packed Pocket Nature Guide published by Johnson Books; “Painted Ladies of North America”.

With dwindling habitat worldwide and assaults on these insects with ever-growing use of chemicals, and intoduced predators, even the tiniest pollinator garden helps. I’m planting lots more agastache, salvias, herbs and lavender this year.



"May the wings of the butterfly kiss the sun
And find your shoulder to light on,
To bring you luck, happiness and riches
Today, tomorrow and beyond."
~Irish Blessing



Joplin Globe column March 29, Speaking of Gardens by Sandy Parrill with extra pictures and text

 

Wednesday, March 26, 2014

Changes



A garden is not made by a gardener alone, or in a day, or even in a generation. It is a sort of hereditary thing that goes on and on, needing cooperation between one and Nature. Nature teaches the person and makes the gardener as well as the garden.

 This is a garden of constant change, both according to the whims of Nature, and of my nature. It is definitely informal, wildflowers and annuals springing where they may, many being allowed to reseed freely; only removed or thinned when they become so thick as to rudely crowd their neighbors out or get crushed underfoot.
 
The “lawn”, as we laughingly refer to it, is a Persian carpet of wildlings: spring beauties, wild phlox, clover, dandelions, bluets, starry chickweed, oxalis, star of Bethlehem and buttercups in the spring. It reverts to a mix of grasses and other green stuff in early summer, when it finally gets mowed. Clover has recently sprung up and is taking over large areas; I can remember many years ago when clover was actually sold as a lawn seed, before lawns became perfectly manicured swards of green with fescue or Bermuda as the preferred grass. I don’t mind. It’s always fun to find a four-leaf clover once in a while and bees and butterflies love it. I steadfastedly refuse to let anyone put weed killers on our lawn, only reseeding with bluegrass in bare spots where digging squirrels, grandkids and droughts have caused bare spots.  

 Shade moves across this almost-acre, leaving us with very few sunny spots and mostly dappled, shifting light under which my beloved wildflowers thrive and multiply, some in beds which circle the stone cottage which shelters us. Some, such as ginger and violets, line the paths, wandering down into the woods where colonies are established under the trees.

 Others simply grow where they want to, and sometimes not in the same places every year. It is always a surprise when a whole group of black-eyed Susans, veronicastrum, columbines or Queen Anne’s lace takes a notion to move 50 feet away to the other side of the house from one year to the next.

 A brick patio, rock garden and pond now occupy the space where the original one-room house once stood. An herb garden replaced a thicket of mock orange some twenty years ago. Most of those herbs are gone now, but the beds and paths remain, with perennials filling out beds where once grew thyme, sage and lavender. The remaining herbs have been moved to a small fenced garden where vegetables once grew. I gave up on the dream of fresh vegetables from our own garden when I got tired of feeding deer, groundhogs and raccoons. The herbs are not to their taste and they leave those largely alone.

 These days we buy most of our veggies at the farmer’s markets and let those growers deal with critter problems. But even that may change this year as we experiment with straw bale gardening in a corner of the herb garden.  It got off to a slow start due to the wintry weather but it’s almost ready to plant with radishes and cole crops now.

 Our street-side garden will see new developments this spring. For nearly a year, water company contractors have been laying a new line along our street, and in the process they have made a hash out of part of the very old iris bed in front of our house. In spite of their promises to “make it look better than it did before” I’m not holding my breath. They claim to be done now, but no one has shown up to fix anything. My patience wore thin so finally I took matters into my own hands; using some big rocks from the property line rock pile, plus rocks and gravel the contractors left lying about, to edge the length of the iris bed and make a rock garden.

 Amazingly, patches of crocuses and daffodils have survived, blooming as if they had never been disturbed in spite of being buried in a foot of gravel and then scraped over with a backhoe scoop.
 

One patch of creeping phlox was somehow missed by that backhoe. This week I added a dozen more to drape over the rocks in front of the remaining irises and daylilies. Low-growing sedums, dianthus, and a few other spreading rock-garden plants will make a living tapestry with them as they grow.

 New color variations of creeping phlox are available now in addition to the old pinks and blues, including a pink and white one called “Candy Stripe”. Creeping phlox is perennial, easy to grow, long lived, spreads rapidly, and needs little care except for a bit of light trimming once it has finished blooming, or not. I always forget and it still looks fine. It’s an attractive, hardy ground cover year-round, resembling a needle evergreen. Barely 4” tall, it effectively smothers out encroaching weeds and is fairly drought-resistant. Blooming (normally) in late March and early April, it invites swarms of early pollinators, bees and butterflies galore to sip of its nectar-rich flowers.

 Creeping phlox loves full sun and good drainage which makes it excellent for growing over retaining walls and down steep slopes as groundcover where it’s difficult to mow. This is the perfect time of year to plant it, in pockets of good compost-rich soil about a foot apart. Be careful not to bury the stem when planting and keep it well-watered until established. Long spreading stems of old plants may get thick and woody and stop blooming well. These can be cut back to encourage new growth that will produce flowers again.

 As we experience more and more effects of climate change, and the weather is seldom “as usual” any more, we need more like these plants that are “bulletproof”, whether they are natives or not. I look forward to many more changes coming to the Chaotic garden.


"One of the worst mistakes you can make as a gardener is to think you're in charge."
 ----Janet Gillespie
                                                                     

"If there's one thing I can say about my garden, it can always surprise me."
----David Hobson, The Mad Gardener
                                                                   
 

 
Sandy Parrill, "Speaking of Gardens" column, The Joplin Globe, March 23, 2014 
 

Monday, March 17, 2014

Time for the Spring Serenade!



A male cardinal in the lilacs keeps announcing how “pretty, pretty, pretty” he is, while close by, his busy mate is paying little attention to his posturing. Just a single pair or two claiming territory here is all that remains of a huge flock of cardinals that crowded our feeders through the snowstorms. The long cold fingers of winter are gradually being pried loose by a gentle but persistent sun, and the soft, moist air smells like new life.

Soon spring peepers will be calling in the pond, looking for mates and laying long, gelatinous strings of eggs that will hatch into tadpoles and polliwogs.

The pond has to be cleaned this week before they arrive so their eggs don’t get destroyed in the process. Tadpoles are good citizens in a pond, eating algae which helps keep the pond clean, while providing food for winter-starved goldfish and koi until they get too big. When they have matured, baby toads scatter through the garden, tiny eating machines that munch bugs and slugs as they grow. We need all the toads we can get as they are the first line of defense in plant protection here at Chaos.


 
















Our pond is about 8’x 15’ and some three feet deep in one end, which is deep enough for koi should we choose to keep them. There were beautiful butterfly koi and fancy goldfish a few years ago, until a marauding raccoon cleaned them out. We haven’t replaced them since, just stocking the pond with feeder goldfish from the pet store in recent years. They grow fast and live a long time, if the raccoons don’t come back for lunch; but if they do, at least we won’t have provided them with an expensive gourmet feast.
I’m not sure yet if there are any fish alive in the pond this year. It might have frozen solid to the bottom with the intense cold, possibly too much for even the cold hardy goldfish. I do hope the leopard frogs that overwinter in the muddy bottom have survived.

The pump was turned off last fall as there is a leak somewhere that kept draining the pond at the rate of 6” or so a week. We couldn’t find it in the pond liner, so the waterfall will have to be dismantled to see if that is where the problem is. Possibly roots from our Crimson Queen Japanese maple growing are through the liner somewhere. 

While the waterfall is torn apart might be a good time to put in a better filter, if we ever decide to try koi again as they need more oxygen in the water than do goldfish. A long-handled leaf grabber made for picking up leaves behind shrubs and flower beds also makes short work of leaves and pond debris, except for what settles to the bottom, but we don’t worry too much about that. A little mud on the pond bottom doesn’t hurt anything, while providing habitat for water insects and little organisms that fish and tadpoles feed on. About every 5 years we drain it and clean it out when it builds up too much.

It’s going to turn green for about four weeks, that’s the nature of a pond. In winter, warm water settles to the bottom, where fish hibernate during cold weather. In the spring, the pond “flips” which means that the warmer water rises to the top and colder water settles to the bottom. As sunlight enters the water, it causes algae to “bloom”, or grow, which can turn water pea soup green. Fish don’t care, but most pond-owners hate it as it isn’t aesthetically pleasing.  The usual reaction is to drain it and refill with fresh water; but that is exactly the wrong thing to do as it starts the algae blooming process all over again with fresh nutrients for algae to feed on.

If your goal is instantly clean water, there are chemicals to kill floating algae and settle particles, especially if you have koi as they eat plants, root in the bottom like the finny pigs they are, and can generally make a mess of a pond. We prefer to do without most of the chemicals, letting plants help achieve that natural equilibrium as they grow, but until they do and begin to shade the water, it is going to be green. Patience is the word here. Besides, I like to save my money for important things, like more hostas, and chocolate.
Keeping 40-50-% of the water surface covered with plants prevents sunlight from reaching into the water, thus starving out floating algae. Annual floating plants like water hyacinths and water lettuce provide shade, and are also natural filters, their roots catching and holding debris which would otherwise make the water murky. Oxygenating grasses float under the surface, also blocking sunlight. Water lilies and lotus shade the water with their big leaves. A coating of a beneficial algae that grows underwater on the sides of the pond also helps keep water clear of the floating kind. A small bale of barley straw helps keep the water clear of filamentous algae; long stringy stuff that covers everything.

 When fresh water is added to top off the cleaned pond, we use a dechlorinator which neutralizes the chlorine, chloramines, and heavy metals present in city water that will kill fish if not treated.  A preventive dose of fish medicine as well helps promote fish health.

We cleaned out our little woods pond also, where the wild things come to drink. It was full of leaves, the raccoons have eaten the fish, but there were water hyacinths  and a water cypress with a new shoot still alive, buried under two feet of leaves! Amazing!
















 
Look who I found in the woods pond! This little leopard frog was cold and sleepy and not moving much but alive and well!

I can’t wait to open my windows and listen to the spring peepers in the clean pond as they sing me to sleep at night. Then I will know spring is truly here.



"The music of all creatures has to do with their loves, even toads and frogs."--Henry David Thoreau

 

Monday, March 10, 2014

Lovin' the Natives, Anyway!


After last week’s rant on planting natives, I should make it perfectly clear that I’m all for it, in case anybody takes me to task. I just want to make sure that when I plant them in our own garden, I know what I’m in for.  Just as non-native or Old World plants can become invasive here, so can local natives if they are planted heedlessly. In their natural range, natives are subject to disease, insects, animal predators and grow with other plants that help keep their populations in check. But when a single native variety is planted in a garden and released from the limiting factors that keep it under control, it too can become invasive when provided with fertile soil, plenty of water and room to roam.
That’s a hard lesson I’ve learned as our garden and I get older. One bed must be extensively re-done this spring because it is so infested with native goldenrod, spiderwort, black-eyed susans, blue star grass, and penstemon that other, smaller desirable natives are having a hard time of it. Shooting stars, native sedums, crested irises, and trilliums are being sorely tested. These native invaders have severely crowded non-natives; iris tectorum, lilies, peonies, clematis, creeping thymes, and columbines that I really want there. And they spread seed so wantonly that even with regular deadheading, they shortly get totally out of control. Their deep roots cling tenaciously to this rocky soil, making them really hard to remove, especially after a winter’s growth. They refuse to be pulled, giving up their top leaves like a lizard losing its tail; having to be dug out, disrupting desirables along the way. Inevitably they insinuate themselves into crowns of other plants, replacing them quickly if they aren’t dealt with. I must admit responsibility for some of them, but I blame birds and wind for the rest.

Not to say that they shouldn’t be planted in a garden. Those aggressive natives are beautiful with echinaceas, monardas, daisies, grasses, phlox and others that can compete well in thoughtfully planned beds.
I love them anyway as a mother loves her incorrigible child, but this year they are all going to be banished to a meadow area where they can merrily reseed and I don’t have to deal with them. It’s way too much work. My goal is to make Chaos less labor intensive as we grow older.  I just want to walk down the paths, tell the flowers how beautiful they are, piddle with them a bit, plant some new things once in a while, watch the birds and butterflies; you know, the fun stuff. I have been mostly successful with some areas, and still tinkering with the rest.

I wish some natives were a little more aggressive, especially out in the woods where I keep dividing and transplanting them so they will carpet the ground under the trees with our hostas, hellebores, heucheras, and other shade perennials. Many wild woods plants are spring bloomers; ephemerals that come up early, put on a show, and then disappear until next year. Trout lilies, Mayapples, Dutchman’s breeches, gingers, Virginia bluebells, hepaticas, ferns, false Solomon’s seal, Jacob’s ladder, violets in every color, bloodroot, false rue anemone, and Jack-in-the pulpit grow out here with woodland phlox, a little annual yellow corydalis, that cursed Virginia waterleaf—I don’t divide or transplant that one however—, and too many others to name, all keeping company with thousands of daffodils, crocuses, grape hyacinths, scillas, pushkinias and azaleas that turn the woods into a blaze of color. This garden is a place to visit to see spring in all its glory.
Virginia Bluebells 



 

 
 
 
 
 
Pink Dutchman's breeches
 By the end of May, though, most of them are gone and only a green carpet of gingers, Solomon’s seal and ferns remains with the hostas and their perennial companions. Other mostly well-behaved natives and non-natives such as creeping veronicas, golden moneywort, tiarellas, leadwort and succulents take their places for the summer.
I add more spring-blooming natives as I find them. Last year it was trailing arbutus (epigaea repens), loved from the Michigan woods of my childhood. An endangered native of the east coast, it is a low-growing member of the heath family, pink-flowered and sweetly scented. Acidic, humusy soil in an oak forest is its natural environment so it was placed at the foot of a white oak where it lived through last season, though this is probably a bit far west for its range. My hopes are high for it, so three more were ordered this spring, along with pink shooting stars (dodecathion) to join existing clumps of white ones.
















Early-blooming native serviceberries have been planted under tall hickories along the south edge of the woods. The fruit is tasty in pies and jam, but I doubt we will get any of the fruits to eat as robins love them better. They are all sprouts from a serviceberry that I once planted closer to the house, not taking into account its suckering ways. Now, those suckers must be dug out each spring to keep them from crowding out a hydrangea that is its bed-mate, and making a serviceberry grove out of the whole area. If I was a harsher mistress of the garden I would pull it out, but I love its delicate white flowers and watching robins plunder the berries in summer.
Planting anything just because the tag says “native” without researching it can cause serious trouble in a small garden. Like with any plant, native or otherwise, find out its habits beforehand to use the right natives for a situation. Plant for wildlife but remember, gardens are for people, too. It’s not fun if the plants make you work too hard.

Many native plants can be found at local nurseries. Missouri Wildflower Nursery will be at area sites this spring including our own Wildcat Glades with plants to sell. Their catalog and schedule is at http://www.mowildflowers.net/


Published in the Joplin Globe, "Speaking of Gardens" by Sandy Parrill   March 9, 2014

 

 

Sunday, March 2, 2014

A Native What?


 
Native is the buzzword in gardening these days. We are urged to plant native, even to the extent of digging up our “ornamentals” and replacing them with native plants that “our” insects and birds love.

But the definition of native is often pretty vague. While I do agree with growing locally native species, it is hard to know just what they are. A true native plant is one that grows in the same habitat in which it originated. It can be native to a continent, a state, or a region. So what is that?  Just because a plant was here when settlers first came, does not mean it “originated” here. Seeds are blown on the wind, carried on tides, in rain, or dropped by migrating birds, which is partly why many of our “natives” are also native to half the rest of the world.
“Native” can be one of the most confusing terms out there for the casual gardener.  Is a plant ok to grow because it’s native to the North American continent? Not necessarily, natives to the East Coast could go nutso in a zone 7 or warmer garden and try to completely take over where cold winters don’t keep them in check (ask me about Virginia waterleaf). Or wither and die because the climate is too hot, dry, cold, wrong altitude, etc. It takes a lot of research to determine which plants are actually native and which have been here so long that like humans, they have evolved, adapted and become naturalized. Though some non-natives truly aren’t suitable to native insects and birds many do provide nectar, habitat and food for them. You see as many wasps, flies, bumble bees and honeybees buzzing around a stand of non-native sedums, for example, as around a patch of goldenrod.

Oh, wait, honeybees aren’t native to North America.  

Food that our birds can eat? Fruits, seeds, nuts that they are used to? Sure. But remember that many of the birds that live here in summer are not “native”, either. This is their summer breeding ground, and they are only here for a few short months until they return to their Central and South American habitats, where the food they eat is unfamiliar to us.
While many native plants are beautiful, many are not suited for small, suburban gardens. They tend to spread with exuberance, look weedy, and as they should go to seed to keep them going year after year as well as providing forage for birds, also look messy and untidy. To gardeners who like to keep things neat, this might be unacceptable.  If you don’t have a big garden where they can grow in sweeps and swaths, you can still plant natives, but limit planting them to those which don’t spread aggressively. Many native shrubs sucker and make thickets of themselves, and while we all admire sassafrass, shrub dogwoods, native viburnums, sumac and others, most of us don’t want to spend all of our gardening time cutting out the suckers to keep them in check or pulling out  all those seedlings, or give up all of our garden room to them. We need to plant natives with caution, just as we should with imported plants. Some of them should just be enjoyed in their natural setting. 

Bidens, or beggar tickseed, is a native annual that is definitely not for the small garden.
It is true in many cases that many non-natives can crowd out and replace our native species (though anything that can crowd out and replace ragweed is a good plant, in my estimation) and those plants should be responsibly eliminated from your garden. But even some natives will do the same if the environmental conditions are right.

White trillium, a beautiful woodland native to grow. Naturalizes nicely, not invasive.
 
We grow lots of natives here at Chaos. Some have been mistakes that we are trying (with little success) to eradicate from our garden where they crowd out other less aggressive natives that we really want. Violets are one of the best examples I can think of, though they were here before we were. Beautiful and loved in verse and art, they spread with such exuberance that they quickly become a nuisance weed. In this garden they have even over-run lily of the valley. That aforementioned Virginia waterleaf makes thick mats of tubers that choke out other desirables. I understand it is endangered in some East coast areas. I would be glad to send them all of mine. Mayapples? Solomon’s seal? Native ginger? Cattails, or heaven help us, horsetail fern? I do have horsetail in my garden, but it is in a barrel water garden in a pot where it can’t escape, because it could take over the known world with a good running start. Native to half the world, including the US, it is not a desirable garden plant.
Many natives have hybridized with imported plants over the last few hundred years to the point where it is impossible to separate the taxonomy, and have become an integrated part of the biodiversity of our continent, as impossible to eradicate as the earthworm, which is not native here, either.
  
In many cases, non-native plants are so heavily into our culture and economics that we could not do without them. Peaches (native to Asia), apples (Kazakhstan), European grapes, oranges (China), cotton (Central America), beets (Mediterranean), tomatoes  and potatoes (South America), soybeans, wheat (Asia, Middle East) and a host of other fruits and vegetables come to us from all over the world to be grown in our  farms and home gardens. Many of the food plants from Central and South American came to North America via early native traders and were already here when early European settlers arrived, so we think of them as native. And, those honeybees! Not a plant, imported from Europe, but who wants to do without them? They are an important part of our economy.  If not for honeybees, what would pollinate all those imported food plants?
So where do we draw the line? Purists would have us grow nothing but natives, but who wants to give up their vegetable gardens? And what about all our native wildflowers that the Europeans “discovered” here, took home and hybridized into myriads of cultivars to sell back to us—are they still considered “native” because they originated here? And I guarantee that I am not giving up my daffodils, crocuses, tulips and hyacinths. I think we can find a balance of native and non-native plants, and our gardens are richer for it, just as our country is rich with a mixture of peoples from other cultures. Diversity is my buzz-word. There is room for a lot of that, taken responsibly and in moderation.
  
Natives and exotics co-exist happly here

The point is, we have to use as much common sense planting natives as we do with planting our beloved imports. Many non-natives are not aggressive, such as hostas, and co-exist beautifully in our gardens with no real threat to our environment. I grow mine with native trilliums, mayapples, ginger, dog-tooth violets, ferns, columbines, bloodroot, and a host of other woods wildlings. I do find that growing some natives is a lot more work than my other perennials, just keeping them in check. 
Be sure if you plant natives, you have room for them to spread, because they will, exuberantly.

But for all the exotics I grow, there is also such a huge population of natives that no animal, insect or pollinator goes hungry here and our garden teems with wildlife. It seems to be in pretty good balance as I seldom have a problem with anything except deer and mammals which, because of human population growth, have lost many of their predators. much of their environment and are forced to live in our back yards, but that is another issue.
Get a good book on North American wildflowers, one that is written for your area, make lists, research anything you are thinking about planting, and if anywhere in the plant descriptions are the words “colonizes well”, “spreads easily”,” reseeds well”, or “good for naturalizing” consider whether it is right for your garden, native or not. Look up invasive plant lists to determine if a “native” is invasive in your area. And yes, read Doug Tallamy’s book, “Bringing Nature Home”. It is an eye-opener.

A good source for information is the Chicago Botanic Garden’s research program: http://www.chicagobotanic.org/research/plant_evaluation/.


And Cornell University has a great site about growing natives: http://www.cornellplantations.org/sites/default/files/Native.plants.Seed_.workshop.pdf