An all-natives landscape is the way to go if nurturing a wide variety of wild flora and fauna is a top priority. But non-natives can make important contributions to the well-being of birds, bees and butterflies.
Invasive plants like buckthorn and purple loosestrife have given exotic plants a bad name. But calling these two "thugs" is a bit unfair. It's not their fault they were set loose in conditions they hadn't been forced to adapt to over the millennia.
In a balanced ecosystem, everything dies at approximately the same rate of natural causes. No species gets the upper hand, as the fancy new import from Europe (Rhamnus cathartica) did while its distant relative, the native Rhamnus alnifoilia, a nondescript dwarf elder, behaved itself. A plant can be a perfect angel in one region and a land-grabbing menace in another.
My glamorous 3-year-old 'Black Lace' sambucus, for example, whose hardiness comes from a Zone 4 elderberry and whose feathery near-black leaves were handed down from a tender European relative, doesn't qualify as a native.
Nor does 'Tiger Eyes' sumac, even though gardeners love its laid-back temperament in comparison with 'Staghorn' sumac, which was born and raised here on the tundra, grows to more than 10 feet and multiplies to form colonies. 'Tiger Eyes' has one less chromosome that causes it to produce brilliant chartreuse flowers and grow relatively slowly.
That 'Tiger Eyes' and 'Black Lace' are sterile hybrids can be both good and bad, depending on how you garden.
All flowering plants can be helpful to wild creatures. Butterflies and bees will take their nectar where they find it. The native cardinal flower (Lobelia cardinalis) is a renowned hummingbird magnet. There are selected cultivars and sterile hybrids in the family, too, that attract hummingbirds because what hummers want above all else is a flower they can monopolize. Long tubular flowers discourage competition from nectar-loving creatures that lack the hummingbird's long beak.
Fragrance seems to attract all manner of wildlife. Native plants have the advantage here because breeders often delete scent to add other traits. Again, there are exceptions. 'Sweet Autumn' clematis, a non-native that puts out masses of sweet-smelling white flowers in late summer, is my garden's top hummingbird draw so far this season, even though its flowers are neither bright nor tubular.
A plant needn't have fragrance, color or a fancy pedigree to attract birds and bees, but it must have flowers. Without flowers it's useless as plant food and therefore as a pollenizer.
Speaking of flowers, a thoughtful reader suggested that removing hosta flowers, the late-summer routine I recommended, is unkind to bees. She makes an excellent point I hadn't thought of, partly because my garden is overrun with bees thanks to the presence of another nonnative species, the upright sedums.
Another reader, Gary Geister, summoned me to his home in Eagan on a Sunday around 10 p.m. This unusual invitation was prompted by my interest in a momentous event under way there, the opening of the stunning and shockingly fragrant blooms of a Nightblooming Cereus, aka Queen of the Night, aka Selenicereus grandiflorus.
This plant is not a native but is noteworthy because Geister has nurtured the plant from a cutting and it's now taller than he is and producing flowers for the first time. This would be a rare achievement for anyone except Geister, who last year took top honors in the houseplant category at the Minnesota State Fair for his gigantic Boston fern.
Bonnie Blodgett can be reached at bonnie@garden letter.com.
THIS WEEK'S TO-DO LIST
-- No need to keep staking those tomatoes. While I was visiting the farm operation where Tangletown Gardens grows the food it serves at Wild Acres, its farm-to-table restaurant in South Minneapolis, I noticed piles of tomatoes at ground level in the fields and assumed they were bush-type plants, the kind that produce all at once. Wrong. Owner Dean Engelmann said staking tomato vines is a waste of time, unless you need to grow plants vertically to save space. He spreads landscape fabric to prevent his crop from rotting and lets the vines grow horizontally. The tomatoes ripen just fine on the ground. He thinks his method reduces fungal problems caused by poor air circulation too.
-- We need rain. Don't let your plants go too long without water. Trees and shrubs especially need your help as they begin hardening off for winter. Recently planted perennials will develop sturdier root systems if encouraged to go deep for water, so keep the sprinkler on a while. Long drinks are better for all your garden plants than quick sips.
-- Keep weeding. Grass allowed to go dormant may be filling up with weeds that will keep the lawn looking green. Don't be fooled. Letting weeds go now will weaken your lawn next year.
-- Continue snipping the fading blooms from your annuals to keep them going. Hold off on replacing bedraggled petunias with cold-tolerant pansies until the heat wave passes.
-- Shear dead flowers off any reseeding perennials you'd rather not see multiply like crazy next year.
-- Exhausted strawberry foliage can be sheared to a half-inch above the crowns and the rows thinned, weeded, fertilized, watered and mulched with pine needles, straw mulch, wood shavings or grass clippings.