Vines with volunteer spirit

In addition to the vines I wrote about two weeks ago that I chose and planted, I’ve got several climbers growing in the yard that showed up on their own. The most useful of these volunteers is Boston ivy (Parthenocissus tricuspidata), the vine that gave the Ivy League its name.

Boston ivy 

    Our Boston ivy appeared on the fence that divides us from our neighbors to the south. It keeps the fence covered in green leaves through the growing season. It’s also acting as a groundcover in a corner where nothing else will grow. 

Boston ivy covers the ground in the dense, dry shade of Norway spruces

The three-pointed bright green leaves turn yellow to scarlet to red-purple in fall. It attaches to supports with holdfasts, sticky discs on the ends of its tendrils, and reportedly grows to 50 feet long. When I follow a shoot I want to remove from a bed or a tree trunk, I can testify that it reaches that length in my yard.

Boston ivy's romantic fall color

    The secret to this vine’s success is that birds like to eat the blue-black berries; Boston ivy is in the grape family. A native of Asia, not New England, the vine has spread around the area as birds drop seeds in favorable growing spots. I don’t regret having it in my garden, because I’d be hard put to find another vine that would cover that fence so thoroughly with so little help from me.

    Two other members of the grape family have also found a place in the yard. I recently spent some sweaty hours pulling wild grape canes (Vitis vinifera subsp. sylvestris) off the shrubs that overhang another section of the same fence. The vines had rooted behind a neighbor’s shed. 

Wild grapes climbing a truck-sized Catawba rhododendron

By the time I noticed them on an infrequent visit to check for places a new puppy could tunnel under the fence, they’d reached far over my head. I had to cut back the leatherleaf viburnum branches (Viburnum rhytidophyllum) that supported them and pull and hack off the vines that came down with them. 

    Wild grapes are nice looking, but I didn’t want their shade to kill the shrubs, and they were bidding fair to take over a large section of the canopy in our yard. Like Boston ivy, they’re imports, in this case from the Mediterranean, and like it they’re spread by birds. I’ll have to remember to be vigilant about checking every year to cut them back as they continue venturing over the fence.

    The third grape relative I’ve found in the garden is Virginia creeper (Parthenocissus quinquefolia, named for the five leaflets that make up its leaves), a cousin of Boston ivy. So far I’m only seeing little patches in uncultivated spots. 

Virginia creeper getting started in a shady area

I welcome this vine because it’s a native and because I love its bright red fall color. When we replace a rotting wooden fence with chain link later this month, I could move one of the young vines to the fence line to create some quick visual screening.

Virginia creeperr's autumn splendor-photo Moralist

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Pollinator-friendly container plantings

Every spring I fill 10 or 12 large containers with flowers and foliage plants for summer enjoyment. At this time of year, there’s a pause in the garden action. Foliage is looking shopworn and dull. A few flowering plants whose growth shut down during the hottest days are coming back to life, preparing for an autumn round of bloom. 

Phlox and a few zinnias are blooming in the late summer lull

Buds are swelling on the New England asters (Symphyotrichum novae-angliae), but few have opened yet. This seems like a good time to evaluate how the container plantings have turned out.

    My favorite pot this year was inspired by advice from reader Patricia McGinnis. Two years ago, Patricia pointed out that instead of neonicotinoid-treated annuals from the garden center, I could fill my pots with divisions of perennials from the garden. What a breakthrough!

    Last fall I’d potted some unneeded perennials with thoughts of passing them on to students at my spring sustainable gardening course (If you’d like to attend the fall course in my garden on Saturdays October 26 and November 2, you can register here through Newton Community Education). Some didn’t find a new home, so I used them to design a pot for a prominent position in the front yard.

Perennial divisions fill out a front yard container

    A purple-leaved heuchera, a nativar, makes a solid mass in this arrangement. Nonnatives provide contrasting foliage: a hosta with chartreuse leaves banded with blue-green and a Japanese forest grass (Hakonechloa macra) with similar yellow-gold coloring. I bought an ostrich fern (Matteuccia struthiopteris) to add some height and added white-flowered wax begonias to bloom nonstop through the season. The begonias' shiny round leaves add another texture to the composition. I knew the fern and begonias were neonic-free, because I’d gotten them at a local farm and garden center that promises untreated plants.

    My next favorite container plantings this summer feature nonnative combinations I’ve been repeating over the years. The “thriller” in these pots is Canna ‘Bengal Tiger’. 

Yellow-striped leaves make Canna 'Bengal Tiger' stand out

I store the roots in the basement through the winter, so I don’t have to worry about neonic-treated replacements. I do the same with the giant tuberous roots of elephant ears (Colcasia esculenta). 

Like cannas, elephant ears need their roots stored indoors in winter

The canna has orange blooms, but I usually cut off the flower stalks so top-heavy plants won’t tip over in a heavy wind. To fill in around the canna stems in a pot that’s located in shade, I added white-flowered impatiens. In two pots on the deck that get afternoon sun, I combined the cannas with cobalt-blue lobelia (Lobelia erinus). 

    This year I’ve had success with another conventional flower choice: a big pot full of apple-blossom pink geraniums. 

Taking a break on a geranium flower. Is it a cricket?

I’d bought three of these plants at a pesticide-free garden center two years ago. I’ve kept subsequent generations alive by taking cuttings in fall. This way I don’t have to search every spring for neonic-free geraniums.

    These are the adaptations that have allowed me to keep neonics out of my pollinator-friendly garden. I’m also happy that my peat-free potting mix is succeeding in providing sustenance for the container plantings.

Coleus thriving in potting mix made from compost and coconut fiber

Corralling climbers

As a garden fills up at ground level, it’s tempting to go for vertical growing space by adding vines. I’ve done my share of this in recent years. I’ve learned that their vitality and vaulting ambition can be either a boon or a disaster.

Honeysuckle can be a pleasure or a monster, depending on conditions

    Take hardy kiwi (Actinidia arguta). I’d received a specimen of its variegated cousin, Actinidia kolomikta, as a membership bonus from the Arnold Arboretum.

Variegated hardy kiwi-photo David J. Stang

It grew moderately where I planted it against a north-facing wall along the driveway. I thought another member of the genus would be similarly docile, and I ordered male and female seedlings so that hardy kiwi could produce grape-sized kiwi fruit.

'Weiki' hardy kiwi

 
     Too bad I didn’t investigate the vines’ growth habits, because both hardy kiwis grew far too vigorously for my purposes. They quickly grabbed low-hanging spruce branches, and they looked ready to conquer the 40-foot spruce within a season. In the wilds of East Asia, they can reach 100 feet by scaling tall trees.

Hardy kiwi reaching for the sky-Jo Zimny photos

    My climbing hydrangea (Hydrangea petiolaris) is the apple of my eye. But it too was a lot more ambitious than I expected. In its first 10 years, the vine got a firm hold on an adjacent oak. It began producing its romantic clouds of white flowers in June. 

Climbing hydrangea in bloom

Instead of twining like the kiwis, climbing hydrangea attaches to its supports with adhesive disks called holdfasts. While covering more of the trunk every year with flowers, it’s also formed a mat on the metal garage roof, creating a microenvironment where Oriental bittersweet (Celastrus orbiculatus), a nonnative invasive vine, has found a foothold. 

At 20 years, the climbing hydrangea has taken over the garage as well as the oak trunk

     Birds must have dropped bittersweet seeds on the roof, and now bittersweet wands are reaching for oak branches. 

Bittersweet berries attract birds, as well as makers of holiday centerpieces

These strangling vines really could kill the tree. I think the only definitive solution will be to cut the hydrangea vine off the roof to eliminate the trap for leaf litter that incubates bittersweet seedlings.

    Less vigorous are the many varieties of clematis I’ve planted. Their flowers are so enticing that I can’t resist buying new ones. Clematis are reputed to prefer having their heads in the sun and their feet in the shade. I’ve found that they also need a minimum of competition and plenty of coddling. I’ve had best luck with an old-fashioned variety, Clematis ‘Jackmanii’. 

Clematis 'Jackmanii'-photo k yamada

It flowers reliably in a sunny spot along the driveway. More recently I’ve tried training clematis up trees and shrubs. They hold on by wrapping their petioles (leaf stalks) around twigs, so they don’t kill supporting plants. 

    As with so many plants in my yard, the controlling factor for my vines is how much sun they get. A clematis growing in sun on a tuteur in the insectary bed produces bounteous elegant blue flowers in May.

Clematis in its happy place

Other clematis vines grow lots of stems and foliage but not many flowers as they climb under the shade of supporting trees. Those too-shaded clematis may not flower profusely, but they don’t try to take over. It’s a delicate balance.

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Making themselves at home

This August I’m keeping an eye on native plants I’ve recently added to the garden. I have to admit that not every native I’ve brought home has settled in easily. But an inventory of the newish plantings under the shade of our dawn redwood (Metasequoia glyptostroboides) shows that some are chugging along.

Before recent additions: shade-tolerant plants under the dawn redwood

    I have high hopes for New York ironweed (Vernonia noveboracensis). This will grow to a shrub-sized perennial, up to 6 feet high and 4 feet wide, with purple flowers in late summer and fall. 

New York ironweed blooming last fall

Doug Tallamy’s Bringing Nature Home web site notes that ironweed is a caterpillar host plant for 18 species of moths and butterflies in my area. So far it’s only about a foot tall, but it has pleasing feathery foliage. When the sheet composting area decomposes enough for planting, I might move the ironweed forward away from the tree, since it grows in sun in the wild.

    I love the dark reddish-brown flowers of Carolina allspice (Calycanthus floridus), a beetle-pollinated magnolia relative also known by the common name of sweetshrub for its flowers’ fruity scent. 

Carolina allspice flowering in Central Park

I first planted this shrub in significant shade next to a Japanese stewartia (Stewartia pseudocamellia). It has survived and flowered, but it’s not making many branches. When we took down the hemlocks near the dawn redwood, a sunnier patch opened up. I took the opportunity to try Carolina allspice again.

    Another native shrub that seems to be thriving is coastal doghobble (Leucothoe axillaris). Its best feature is its low, arching sprays of shiny leaves. Native plant expert William Cullina explains that the common name describes the tangled thickets leucothoe creates in the wild that even a dog can’t wriggle through.

Shiny foliage of coastal doghobble

     Leucothoe is often recommended with other broadleaf evergreens for foundation plantings. I inherited lots of those: rhododendrons (Rhododendron spp.), mountain laurels (Kalmia latifolia), and Japanese pieris (Pieris japonica), but I’d never grown leucothoe until I realized it was a native that might do well under the shade of the dawn redwood, and so it has. Those leaves are still shiny and pristine in August, which is more than I can say for most of the foliage in the yard. I haven’t seen any flowers yet. They’re going to be little dangling white bells.

    By the way, neither Carolina allspice nor the leucothoe is actually native in the Northeast. They’re both from the Southeast, but since they can grow here, I’ve decided to give them a try. We each get to decide how native our natives are going to be. If I were a true purist, I’d restrict myself to plants from my ecoregion, the Boston Basin. So far I’m not willing to be that exact.

The Boston Basin is my ecoregion

    A true New England native is already established next to the dawn redwood: winterberry (Ilex verticillata). This has grown into a small double-stemmed tree and produces masses of red berries that birds eat during the fall and winter. I’m glad to know that it also provides caterpillar forage for 42 moth and butterfly species.

Winterberry fruit in late fall

 

Shrinking the lawn

Evelyn Hadden’s book Beautiful No-Mow Yards recently reminded me that I still have a grassy lawn. The book spotlights gardeners around the country who have dispensed with lawn, replacing it with options ranging from groundcover beds to meadow gardens to paths leading between garden “rooms” full of beautiful perennials, shrubs and small trees.

Native perennials replace lawn in Robin Wilkerson's garden in Lincoln, MA

    While I’ve long aimed to eliminate lawn, I realized that I’m not ready to give up grass completely. What I’d like would be to reduce it to an area of transition between beds. I still like the look of the visually quiet mowed surface as a foreground for other more exciting plants.

Lawn makes a nice foreground

    Even a low-input lawn like ours is environmentally undesirable. Our lawn uses fossil fuels for mowing, but it’s getting by without fertilizer, weed-killers, or extra water. It’s still a pretty barren habitat for native insects and birds, compared to other ways garden space can be used.

    My lawn-reduction effort started back in the 1980s when I replaced a part of the front lawn with vinca (Vinca minor, also called periwinkle). That wasn’t so much a principled choice as an acknowledgment that grass wasn’t going to grow under the shade of the Norway maple street trees. The groundcover bed has proved to very low-maintenance, needing only occasional weeding to remove maple seedlings.

Vinca groundcover beds are neat and easy to maintain

    Next I dug out some grass around a fish pond we’d installed in a circle of lawn in the backyard. I planted perennials and dwarf trees instead, including two dwarf blue spruces (Picea pungens) that I particularly like. As they slowly enlarge, I’ll need to decide whether to move them and choose something smaller. Meanwhile, they’re doing their part by filling what would otherwise be lawn and offering shelter for moths and butterflies.

Perennials and blue spruce replace some lawn

    Two years ago I took out a big chunk of lawn when I created two perennial beds off the back deck. That and a bluestone path eliminated about 600 square feet of grass. While we had school-age kids, we wanted an open space outside the back door where they and their friends could run around. Now it’s nicer to turn that space over to flowers and pollinators, especially because it’s one of the sections of the yard that gets the most sun.

 

New beds and path where lawn used to be

    Last March I added to a bed with a sheet-composting project. As you can see, the mound of wood chips and compost is starting to settle. With continuing decomposition, after two years, it should sink to the level of the surrounding lawn. Then it will provide a rich environment for flowering perennials. I’m planning to move some there from places that have gotten too shady. If there’s space left, I can add new ones too.

Sheet composting mound is subsiding

    My next plan is to repurpose some lawn space across from the sheet composting. Outside the vegetable garden fence, I could create a cutting garden. It would be nice to grow dahlias, zinnias, and snapdragons just for enjoying indoors in a vase. Why not?

Wouldn't flowers look better?

Insect superfoods

Visiting Coastal Maine Botanical Gardens this week brought some encouraging news about insect-friendly plantings. The designers had showcased many of the same flowers I’m growing to attract insect visitors, some inside the butterfly house near the entrance to the garden. Monarchs fluttered around this enclosed space, lighting on swamp milkweed and purple coneflowers. I spotted two species of caterpillars on stalks.

Monarch on purple coneflower in the butterfly house

   
    Planting for insects isn’t just for pollinators. It’s also intended to help leaf-eating insects, particularly caterpillars of moths and butterflies. 

Monarch caterpillar

Therefore Thomas Berger performed a useful service by cross-referencing lists of the best plants for these two purposes to derive a master list of insect “superfoods” posted by the Ecological Landscape Alliance. At the top of the section on herbaceous plants were goldenrods, asters, and sunflowers.

    Goldenrods support 11 species of specialist bees—bees that can only feed on a limited group of native flowers—and 115 kinds of lepidopteran caterpillars (caterpillars of butterflies and moths). Asters and sunflowers aren’t far behind. Goldenrods attract monarch butterflies and feed their caterpillars, making them second to milkweeds for supporting these fast-disappearing butterflies. 

    This is good news for my garden, because lots of goldenrods and asters are growing here already. I started some goldenrod from seed years ago. Patches of goldenrod here and there mark its spread around the yard. Unfortunately I didn’t keep a record of which species I’d planted. From photos, I suspect it was blue-stemmed goldenrod, Solidago caesia. Two years ago I bought some sweet goldenrod, Solidago odora, for a new perennial bed. Both native species have proven to be easy to grow and free-flowering.

    Goldenrods are members of the Compositae, also called Asteraceae, a useful family of plants because their central discs are made up many tiny flowers, each with pollen to offer. 

Visiting a daisy flower is an efficient way to collect pollen

The “petals” of the daisy-shaped blooms are actually strap-shaped flowers too. So an insect visiting one of these composite flowers gets lots of pollen with minimal travel. Goldenrod blooms are small, but if you look closely, you’ll see they share the family shape. 

Goldenrod's tiny daisy flowers

 

By the way, goldenrod doesn’t trigger hay fever. It has sticky pollen that doesn’t blow around like that of real culprits, such as ragweed.

    I’m growing some New England asters (Symphyotrichum novae-angliae) with pretty blue flowers. But aster volunteers are much more plentiful in the garden. In the past few years, a white-flowered type has popped up in lots of part-shaded spots with no effort on my part. I suspect it’s white wood aster, Eurybia divaricata.

Aster volunteers

    Last week I wrote about my bad luck growing sunflowers. I learned from Berger’s post that Helianthus annuus, the garden or field sunflower, was brought to New England by Native Americans as an agricultural crop and isn’t native here, although our local specialist bees can still use it. A native option is woodland sunflower, Helianthus divaricatus. Meanwhile, I’m growing oxeye sunflower, Heliopsis helianthoides, also called false sunflower, a different native genus but useful to pollinators too.

Oxeye sunflower

 

A bit of progress on neonics

This week I planted a sunflower that I’d bought at Home Depot. My reason for shopping at a big box store instead of a local garden center was the progress Home Depot has made toward phasing out neonicotinoid insecticides from their plant offerings.

Sources of neonic-free plants can be hard to find

    Thanks to a campaign by Friends of the Earth and others, Home Depot yielded to pressure and promised that plants they sold would be neonic-free by 2019. Neonics are systemic pesticides that are used to promote growth and keep plants on retail benches looking fresh and unchewed. The problem is that they also kill or disable bees and other pollinators.

Neonics can kill bees that visit treated plants

     Once a seed or plant has been treated, neonics persist in plant tissues for years and can even be transmitted to nearby plants through soil and water contamination. In 2014, Friends of the Earth found neonics in more than half of bee-attracting commercial nursery plants bought at a broad sample of garden centers and big box stores in the United States and Canada. 

    As they worked on purging neonics from their supply chain, Home Depot took the interim step of labeling neonic-treated plants they sold. 

Home Depot's spin on neonic labeling

They got some negative responses to this practice, because it raised awareness of the danger. Meanwhile, other sellers continued selling treated plants without the warning. This year Home Depot says that 98 percent of the plants they sell are untreated. They attribute the remaining 2 percent to state regulations requiring neonic treatment of certain plants. 

    Meanwhile, I’ve failed totally at growing sunflowers from seed in my garden. When I plant seeds, something bites off the seedlings as they emerge. I imagine this is a squirrel who likes the taste of sunflower sprouts. I’ve tried starting the sunflowers indoors and transplanting young seedlings to the garden. These young plants too have been irresistible to hungry wildlife. That’s why I decided to buy a husky sunflower whose stems are already tough enough to withstand squirrels’ teeth. 

    I bought what was offered: ‘Sunfinity,’ a hybrid that grows to only 3 feet and produces multiple 3- to 4-inch flowers through the season. This plant won’t offer seeds for the birds. It produces nectar for beneficial insects, but it’s sterile, with no pollen. 

Sunflower 'Sunfinity'

This is not the sunflower of my dreams. I’d envisioned something taller with a few dinner-plate-sized blooms packed with seeds. Planting so late, though, I’ve got a chance of seeing the flowers bloom.

    When I encountered the plant, it was showing some flowers. I took care of that by planting it in the vegetable bed, where something quickly bit off the young blooms. 

Stripped

 Undeterred, the plant put out some more buds that are now opening. I imagine that this back and forth will continue into the fall.

Trying again

    I wish Home Depot offered some unhybridized sunflowers, straight Helianthus annuus. Those would do more for pollinators and birds in the garden. But I’m glad to know that my Sunfinity is neonic-free. There’s no point in a pollinator garden that kills pollinators.

First do no harm