Hopes for spring

The post-holiday doldrums have set in, and I’m looking for garden planning projects to remind me that spring is on the way. Inspired by Kim Eierman’s book, The Pollinator Victory Garden, I’m developing a short list of generously flowering perennials to provide my best pollen and nectar buffet ever.

Robin Wilkerson's Lincoln, MA garden in August 2017 - a pollinator feast

   May and June bring the most flowers in my garden, with another surge in October. My goal is to boost “floral resources” from July through September, when there’s less forage available for pollinators here. To produce the most flowers for visiting bees, flies, beetles, moths, and butterflies, the new plants will need as much sun as they can get in our yard. That’s why I’ll plant them around the garden pond, one of the sunniest areas. To date, the pond been surrounded on three sides by dwarf conifers, a Japanese maple, and a few perennials. 

Looking sad now, but you can see there's some space for flowers

    When the molded plastic pond liner was installed in 1997, its rim was covered with long pieces of bluestone, and smaller bluestone rectangles were dotted around it in a pleasing irregular pattern. I’m proposing to lift the smaller stones where I can to make space for summer bloomers. 

    Most of my summer flowers are yellow or orange. Around the pond, I’m going with purples and pinks. Working from lists from Kim’s website, ecobeneficial.com, and the Native Plant Trust, I’ve chosen some possibilities. They’re all native to Massachusetts, and this time I’m going to insist on straight species, not cultivars. 

    A cultivar is a plant that’s been selected from among the natives and reproduced asexually—through cuttings, divisions or tissue culture—to preserve some desirable characteristic. The problem is that new traits humans like may confuse insects, as when flower color or bloom time changes. In general, I’ve accepted cultivars that look similar to the straight native species as sustainable enough, but not this time. This bed will be completely pure.

This yellow tickseed, Coreopsis 'Zagreb,' is a cultivar that looks like the straight native species

    Here are some of my choices: I’ve been wanting to grow Joe Pye weed (Eutrochium maculatum) or its coastal cousin (Eutrochium dubium). 

Joe Pye weed

I’ll give anise hyssop (Agastache foeniculum) another chance. 

Anise hyssop-photo R. A. Nonenmacher

I’ve stayed away from beebalm because I feared it would take over the garden. Now I’ll try some, possibly spotted beebalm, AKA horsemint (Monarda punctata), which has intriguing flowers combining pinkish-purple, green, beige, and maroon. 

Distinctive horsemint flowers

I’ve got to try mountain mint (Pycnanthemum muticum), which also has muted flower colors. It’s reputed to be a superstar for attracting pollinators.

Mountain mint is a pollinator magnet

And asters will fill in the gaps, not just late-blooming New England aster (Symphyotrichum novae-angliae) but possibly also New York aster (S. novi-belgii) or smooth aster (S. laeve), both of which flower during my preferred summer window.

Smooth aster starts blooming in early September-photo Heike Löchel

    I’m hoping to combine different flower forms, from the daisy-shaped aster flowers to beebalm’s tubes and Joe Pye weed’s compound balls. That’s to cater to the preferences of the different insects I hope to attract.

Butterflies with long tongues can sip from tubular flowers

    I may even be able to avoid plastic pots and buy some of these as bare root plants. Updates will follow.

Uncomfortably warm

We had record high temperatures last weekend, up to 74 degrees at Logan Airport on Sunday, the warmest January temperature ever recorded in Boston. For us humans, it was a pleasant break from winter cold. Scientists in town for the American Meteorological Society’s annual meeting linked the freakish weather to the trend toward global warming.

    After my friend Amy noticed that some blue vinca flowers (Vinca minor) had opened, I checked and found some in my front yard too. 

Vinca flower looking peaked after Friday's cold

My Asian witch hazel (Hamamelis mollis) is in full bloom in the backyard. The danger is that these early bloomers started up their spring metabolism too soon, and they’ll suffer for it. By Friday, we were back to a windchill of 5°F.

So far the witch hazel flowers are holding up

    I’m hoping that despite the White House’s attempts to deny what everyone else knows, we’re finally squaring up to serious action to address global warming. Meanwhile, though, we’re warned that even if we immediately reduced carbon pollution radically, we’d still have to expect climate effects that have already been set in motion.

    In the garden, I’m afraid this doesn’t mean I’ll be picking mangoes and pineapples. 

We could end up with waterfront property due to sea level rise, but the palm trees are unlikely

Instead, I’m expecting more winter warm spells alternating with vicious cold without snow cover. That’s already been happening in recent winters, and it’s especially hard on my shrubs and vines.

    I particularly notice the effects of uneven winter temperatures on a climbing rose that grows near the house on the garage and an adjacent pergola over the garden gate. 

    When I started the garden thirty years ago, I planted Rose ‘New Dawn,’ in this spot. I learned later that some garden designers regarded ‘New Dawn’ as a boring cliché, but to me it was the epitome of rose charm. I pictured a romantic cloud of blush pink roses spilling over the gateway. 

'New Dawn' is my idea of a romantic climber

After a few years, that did happen—sometimes. A winter warm spell followed by a cold snap could kill back even this tough survivor.

Rose canes exposed to chilling winds. Cross-vine leaves are still clinging on in January.

    At first the vine bounced back, quickly sending up new canes to replace killed ones. In the last couple of years, it seems to be struggling just to survive, and flowering has been sparse. ‘New Dawn’ is rated as hardy to Zone 5, meaning that it can bear the cold down to -20 F, lower than what we get in this area. I think it’s the cold, drying wind when there’s no insulating snow that’s depleting the vine’s reserves as the assault is repeated year after year. It’s got only so much stored energy for repairs.

    To help ‘New Dawn’ and my other favorites survive the new climate reality, I’m resolving to surround their bases with some compost and composted cow manure next spring to help them store up energy during the warm season. To me, shrubs wrapped in burlap through the winter are an eyesore. 

Poor thing!

But I might break down next fall and pile up some leaves or soil around shrub and vine crowns for a little extra insulation. As I post this, there's snow on the ground again, thank goodness!

Another reason to keep garden waste at home

A new book that came in the mail, The Pollinator Victory Garden by Kim Eierman, made me glad that I'd started a brush pile this fall. Until recently, I couldn’t picture a suitable spot for this amenity in my third-of-an-acre suburban lot.

    The ecological reason to cultivate a brush pile is to provide wildlife habitat. Kim Eierman’s book focuses on insects, so she recommends brush piles as shelter for bees. She points out that 30 percent of North America’s 4,000 native bees are cavity nesters. They need safe small spaces where they’re sheltered from the rain. Some find cavities that birds or other insects have made in dead trees, stumps or fallen logs.

Carpenter bees are cavity nesters-photo Anita Gould

    Other than wood chip mulch, there’s a shortage of dead wood on the ground in our yard, due to my previous habit of cleaning up at soil level. I now realize that’s unnecessary and eliminates potential habitat for creatures I want in the garden. I’m allowing dead tree limbs to lie on the ground in inconspicuous spots, but it’ll be a while before they soften and rot.

This downed tree in a local conservation area offers shelter for native insects

    The brush pile I’ve started intends to serve a dual purpose: containing our over-enthusiastic puppy and offering shelter for wildlife. Eager to play together, our Lola and Ruby, the dog next door, discovered spots where they could dig under the wooden fence between their yards. 

"Who, me?"

They applied themselves with energy. I went to work reinforcing our perimeter with wire fencing held down with bricks, paving stones, and any big rocks I could find. 

    There was a vulnerable space between two wire compost bins and the new chain link fence that joins the wooden fence line. I blocked off this corner with more wire fencing. In addition to foiling a homegrown prison break, the narrow, enclosed space now houses my new brush pile. As I build up the pile, I plan to add bundles of twigs tied with twine to keep insect nests dry.

Starting the brush pile with pine branches that came down in a heavy wind

    Cavity-nesting bees also find spaces inside plant stems. I’m already accommodating them by letting stalks stand through the winter. We’ve got elderberry, raspberry, and hydrangea bushes, so I’m glad to hear that their pithy stems make particularly good nesting spots.

Spongy stems of oak leaf hydrangea can be excavated by bees to make nests

    I love the idea of an insect hotel. That’s a human-made collection of promising nesting material, such as bunches of hollow stalks tightly packed together, clumps of dry leaves, cut lengths of bamboo stakes, ceramic blocks with small cavities built in, and tree branches or chunks of lumber with holes drilled for convenient insect access. 

This is an insect hotel in Germany. Cool, right?

The thing about this approach, though, is that the cavities need periodic cleaning. I’m not sure I can be counted on to clean an insect hotel on a regular schedule. For now, I’m letting nature do the work.

    After reading the first chapter of Kim’s book, I can already tell it’s going to up my game. While I wait to put Kim’s advice into practice next spring, I’ll be throwing fallen branches on the brush pile instead of filling yard waste bags.

 

Pest control without pesticides

It’s nice to hear about solutions for insect problems other than spraying pesticides. I’ve been a fan of biocontrol—introduction of nonnative insect predators to reduce populations of problematic insects—since I was able to stop spraying my trees for winter moth (Operophtera brumata). 

Winter moth-photo Ben Sale

This lucky turn of events came about because UMass entomologist Joseph Elkinton built up populations of Cyzenis albicans, a tiny parasitic fly that kills moth larvae. As substantial fly populations were established, winter moth damage became a non-issue. The parasitic fly attacks only winter moth and doesn’t prey on native insects.

    Since the winter moth success, I’ve learned about another clever use of a specialist insect, Hypena opulenta, a moth native to Ukraine. This moth eats the leaves of black swallow-wort (Vincetoxicum nigrum) a pernicious vine from the same region that’s causing problems in New England and elsewhere. 

Black swallow-wort, a nonnative invasive vine

Among other negatives, swallow-wort tricks monarch butterflies into laying eggs on its leaves, where larvae starve because they can’t eat swallow-wort foliage. Struggling monarchs don’t need this added trouble.

A monarch nectaring on the real thing, native showy milkweeed

    Boston’s Arnold Arboretum started releasing the Ukrainian moths this spring and saw them defoliate swallow-wort significantly in a test plot. Biocontrol is particularly welcome in the case of swallow-wort, because it’s really hard to pull out. Stems break off at ground level and send up new stalks. Some towns have asked Boy and Girl Scouts to pick unripe pods of swallow-wort vines and dispose of them before they can spread their seeds to the wind. This still sounds like a good idea, because the moths aren’t expected to wipe out swallow-wort, just reduce and control its population and spread.

    Meanwhile, scientists at the University of Rhode Island are working to establish the best predators for red lily beetles (Lilioceris lilii) that chew lilies, especially the Asiatic species, into unsightly stumps covered with beetle excrement. They've released three kinds of parasitoid wasps and are achieving some success.

Red lily beetles at work on a lily stem-photo Charles J Sharp

    When I started gardening back in the 1970s, organic gardening guides promoted the idea of companion planting, claiming that interplanting with herbs or annuals would keep chewing insects from damaging vegetable crops. 


    Unfortunately, this conventional wisdom often turns out to be wishful thinking. Thomas Christopher, in a recent blog post, traces the advice back to Ehrenfreid Pfeiffer, an early 20th century soil scientist and advocate of biodynamic gardening. Pfeiffer conducted bogus experiments purporting to show that certain plants were compatible. The idea was picked up and spread by J.I. Rodale, publisher of Organic Gardening. The nasturtiums, alyssum and marigolds I still dot around my vegetable bed originate from this myth. Most gardeners never traced it back to its faulty source.

Marigolds are nice, but they're probably not protecting my vegetable plants

    Christopher directs readers to a reliable review of companion planting by garden designer Robert Kourik. The scientific papers he cites show a more nuanced picture. Many of the usually recommended flowering plants don’t help to defend food plants, but some do attract beneficial insects that can reduce populations of leaf-eaters. Another reminder of the importance of healthy skepticism about gardening advice.