Do 'nativars' count as native plants?

For the purpose of supporting biodiversity in general and native insects in particular, do we have to grow only the straight species or “wild-type” of plants that grew in our region before European settlement? What about improved versions of those plants, referred to as cultivars or “nativars”? This turns out to be a complicated question.

    Unless you’re shopping at a dedicated native plant nursery, you’re likely to find few unimproved natives at the garden center. Most plants offered as natives will be cultivars that have been selected by horticulturists for desirable traits such as bigger, brighter flowers or unusual foliage color. You can spot a cultivar by a name in single quotes: for example, Echinacea purpurea ‘Sundown’ is a purple coneflower cultivar.

'Sundown' was selected for its petals' orange tint-photo Mike Peel

    Sometimes a spontaneous mutation occurs in a plant population. An observant nursery may notice the plant’s changed appearance and decide it has market value. Other cultivars are purposely created through many generations of breeding or even through genetic modification. Some are hybrids between two species. 

     Are nativars useful in pollinator gardens? It depends. Selection for horticultural use may change flower size, color, time of bloom, or foliage color. Any of these could confuse insects seeking pollen and nectar or could mean that bloom doesn’t occur when the insects need it. 

Pollinators have evolved to synchronize their life cycle with bloom times of flowers they need

Double flowers are often sterile, because in the breeding process, pollen-carrying stamens have been replaced by extra petals. These won’t offer visiting insects any reward at all.

Echinacea 'Razzmatazz' won't help pollinators

    In general, it seems that the more closely a flower resembles the straight native’s, the more popular it will be with insects. It’s an area of active research. Doug Tallamy and Emily Baisden have found that woody plants with purple, blue or red leaves are not useful to leaf-eating insects, probably because of the anthocyanins that give leaves their pleasing colors.

Heuchera 'Amethyst Mist' is pretty, but not attractive to leaf-eaters

      Annie White intensively studied pollinator visits to test gardens of native perennials and cultivars of the same species at the University of Vermont. Delaware's Mt. Cuba Center ran another perennial trial. 

Doug Tallamy and Emily Baisden vacuum up insects for study at Mt. Cuba Center

     In general, the unimproved native flowers attracted more insects, but some cultivars were also winners. A culvers root (Veronicastrum virginicum ‘Lavendelturm’ and a garden phlox (Phlox paniculata ‘Jeana’) were visited by more insects than their straight native counterparts. Researchers speculate that this is because the culvers root bloomed for longer than the straight species and the phlox had shallower flowers that made nectar easier to reach. Hybridization made flowers less useful to insects when it radically changed flower color or reduced production of pollen and nectar.

Small, shallow flowers of Phlox 'Jeana' make nectar access easy

    For gardeners who’d like to participate, three universities are running a citizen science project called Budburst that invites us to plant some flowers from a list and contribute scheduled, structured observations of their insect visitors.

    What can we take from the preliminary research? Generally straight natives seem to do the most for insects, but many nativars are useful too. We can encourage our garden centers to stock the unimproved natives. And plant breeders can help out by selecting and marketing flowers that benefit pollinators.

Squeezing in native plants

When I read Douglas Tallamy’s book Bringing Nature Home, I was inspired to add native plants to my garden to support native insects. There was just one problem. My garden was already full.

    As a gardening beginner, I chose plants without thinking about their environmental role. By planting what I liked and could get to grow and bloom in my yard, I ended up with a mix of natives and imports. I’m fond of the nonnatives that have settled in successfully, and I had no intention of booting them out.

Doublefile viturnum isn't a native, but I love it

    Instead, I started looking for places to shoehorn in some new plants. Sometimes I could open new areas to cultivation, as by subtracting lawn or removing colonizers such as tawny daylily (Hemerocallis fulva) that didn’t appeal to me. 

Tawny daylily, native to Asia, pops up everywhere-photo A. Barra

More often, opportunities arose when something I’d planted didn’t make it. 

    One chance to add sun-loving natives came when we took down a white-flowered redbud (Cercis canadensis f. alba) that had become ungainly. Daylilies I’d planted nearby when the tree was small had stopped blooming as it cast more shade. Without the tree, they took heart and sent out flowers the next summer. Around them there was space for threadleaf coreopsis, or tickseed (Coreopsis verticillata), which has gradually spread along 10 feet of border, weaving around the perennials and low shrubs in the bed. 

Native threadleaf coreopsis coexists happily with daylilies

The tickseed is a native that draws insects to the area. Behind it, I scattered seeds of common milkweed (Asclepias syriaca). My reason for introducing this possibly aggressive spreader was to attract monarch butterflies, which need milkweed leaves to feed their caterpillars.

I hope monarchs will lay eggs on this common milkweed

    When I planted some dwarf trees around a garden pond, I chose Colorado blue spruces (Picea pungens) for two of the corners. Native to Massachusetts? Well, no, but they’re native to North America, and they provide shelter for moths and butterflies during the summer. I’ve since learned to check a plant’s native range more carefully.

Blue spruce fits in nicely around the pond

    Several native flowers moved in when I converted half of the vegetable garden that was too shady to produce food into an insectary bed, a pollinator garden that also offers benefits for beneficial insects and native leaf-eaters. There I can grow native perennials that are comfortable with part shade. Two kinds of milkweed (Asclepias incarnata and A. tuberosa), oxeye sunflower (Heliopsis helianthoides), garden phlox (Phlox paniculata), black-eyed Susan (Rudbeckia hirta), and purple coneflower (Echinacea purpurea) mix with pollinator-friendly annuals not native to New England, such as zinnias (Zinnia elegans), sweet alyssum (Lobularia maritima) and cosmos (Cosmos bipinnatus).

Insectary plants offer food and shelter for native insects

    A new perennial bed off the back deck offered lots of space for sun-loving natives. That’s a story for another day. Meanwhile, the sad decision to cut down our hemlocks (Tsuga canadensis), native evergreens that were under attack from a nonnative insect, opened up a back corner of the yard. I’m adding native shrubs and perennials there, seeing which ones will take hold with a minimum of watering. That may develop into the garden’s most authentic New England thicket.

Allegheny spurge, a native pachysandra, getting a foothold at the back of the yard

 

Nature: it's right here

It’s frequently said that people can achieve mindfulness, access tranquility, restore emotional equilibrium, and enjoy a host of other benefits by being “in nature.” 

Nature writ large-photo NPS

This prescription always troubles me. I know what people mean: they like to visit the forest, the mountains, the seashore, or whatever wild landscape is their spiritual home when they’re feeling troubled or overwhelmed. That’s healthier than a lot of the choices that may beckon when you want to make yourself feel better.

    My problem is with the idea that you have to go someplace special to be “in nature.” Nature is everywhere. I admit that I usually envision nature as outdoors. It’s indoors too, and even inside our bodies, as demonstrated by recent revelations about the gut microbiome.

Microbes are part of nature too-image USDA

    You don’t have to fly to a natural park or drive to your local conservation area to find nature. When I’m traveling around a scruffy town near Boston for work, I’m cheered by evidence on every block of plants taking back territory from the barren landscapes constructed by humans. Seeds fall into cracks in the sidewalk. Roots push their way from the curb strip or front yard to the next patch of open soil. To my mind, those pioneers count as nature too.
 

Spontaneous and beautiful

    There’s a problem with defining nature as just what you find in seemingly pristine wilderness areas. It’s important to conserve the last areas of virgin forest, unspoiled seashore, and underwater habitat. But if we insist that nature exists only where there’s no human footprint, we’re leaving out most of the world’s ecosystems. We need to support biodiversity even in cities and suburban areas. 

    The movement to plant native plants and pollinator gardens is worthwhile because it’s possible for humans to live comfortably alongside plants that restore habitat for animals, especially native insects. A New England gardener including some bee balm (Monarda didyma), Joe Pye weed (Eutrochium maculatum) or aster (Symphyotrichum novae-angliae) in her garden enables a small increase in biodiversity. 

Cosmos in the curb strip supports native insects

All the yards together can do a lot, even when native plants don’t predominate in every garden. If we think the suburbs aren’t part of nature, though, we won’t see that we have a part to play.

    As effects of global warming progress, we urgently need to bolster ecological services provided by plants, such as cooling, air purification, and carbon sequestration. Street trees, long-lived plants in our yards, or even a few shrubs or small trees in concrete planters in a city center all contribute toward combating the effects of climate change. 

A street tree doing its part

Each tree uses the same natural processes plus water, air and the sun’s energy to bind carbon in its tissues and the surrounding soil. It doesn’t have to be part of a forest for that to happen.

    We humans are part of nature, and so is our local habitat. That means we need to be good stewards of every part of the world. It also means we’re never marooned outside nature, which is a thought I find comforting.

I'm off to British Columbia. See you in two weeks.

Rascally rabbits

“How did you find out how to get in there!?” I yelled. This heart’s cry burst from me Sunday evening, when I spied a rabbit inside the vegetable garden, which is surrounded by what’s supposed to be a rabbit-proof fence. The startled rabbit made a quick exit under the gate. 

Eastern cottontail rabbit-photo Gareth Rasberry

    Getting closer, I could see it had dug a shallow trench that enabled it to slip under. The bottom bar of the gate is two inches above the ground. Wire fencing hanging an inch lower attempts to block the opening, but with nothing underneath but diggable soil, it was a matter of time before some enterprising rabbit would make it through. This one had finally solved the problem.

The rabbit figured out how to slip under the gate

    Traveling around the state talking to fellow gardeners has taught me that the number one question on people’s minds is how they can keep wildlife, especially rabbits, from destroying their plants. I feel pretty useless when people ask for my solution to this problem. All I know to recommend is installing a wire rabbit fence and planting clover.

    In the last few years, rabbits have become permanent residents in my yard. They chomp newly emerging perennials down to the ground in early spring. Marigold seedlings I planted in June have lost all their leaves. The hallmark of rabbit damage is clean cuts. With both upper and lower incisors, they can slice off stems and leaves as effectively as handheld clippers.

Marigold stripped by rabbit's teeth

    The eastern cottontail, Sylvilagus floridanus, ranges across the Americas, from southern Canada to South America and from the east coast as far west as New Mexico. Each rabbit defends about half an acre of territory. As we know, they’re good at reproducing.

    Various authorities recommend plants that rabbits supposedly don’t eat. My credulity is undermined by seeing the same herbs listed as attractive and unattractive to rabbits. 

Basil either attracts or repels rabbits

Bunnies reportedly don’t like the smells of onions and garlic. Home remedies circulate for spraying plants with concoctions of these and repeating the process after every rain. Even proponents of these deterrents admit that when food is short and population pressure high, rabbits will eat whatever they can, even if it tastes nasty. 

    In wild places, rabbits eat grass in summer, twigs and bark in winter. They live in young forests, where they find shrubs and small trees interspersed with open space—sort of like typical suburban yards. I do find that they like to eat clover, and I believe that filling in bare patches in the lawn with clover seed helps a bit to keep rabbits out of the perennial beds.

Rabbits are welcome to nibble clover in the lawn

    Then there’s that supposedly impenetrable wire fence, the one buried a foot deep so they couldn’t tunnel under—except at the gate. I’m willing to share the rest of the yard, but I cherished the hope of keeping rabbits out of the vegetable garden. 

 

Lettuce for humans, not for rabbits

Next week’s task will be to set in bricks under the two gates. Am I smarter than a determined rabbit? Time will tell.