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

The little squirrels that could

I'll be selling gardeners' gift baskets at the farmer's market in West Newton, MA 10-2 on June 23, June 30, and every other Saturday thereafter until October 6. Stop by and say hello if you're in the neighborhood! The market is on Elm Street between Washington Street and Webster Street. 
 
Baby needs acorns—that seems to be the imperative for squirrels in my yard at this time of year. Local squirrels are in high gear, digging everywhere. 

Squirrels are persistent in their search for food. They've got all day.

I wake in the morning to find holes dug every six inches in the wood chip paths. There are few edible seeds or nuts around at this season. Squirrels are digging for food wherever soil is loose.

Wood chip paths make for easy digging

    Whatever I plant in the ground is in danger of being thrown back out by foraging squirrels. This year’s plan to grow vegetables and berries in containers on the deck is in serious jeopardy unless I can keep squirrels out of the pots until the plants are firmly rooted.

      Checking Google, I learn that other people are having the same problem. 

Can you see where squirrels dug a hole in the bottom right corner of this pot?

Writers promoting “natural” gardening recommend non-toxic repellents: human hair or dog hair, cayenne pepper, or bone meal spread on the soil surface. Folk remedies like these get passed on from gardener to gardener, but I’ve never found they had much effect on wildlife.

    Instead, I’m opting for mechanical barriers. One recommendation that recurred in my Internet search was to lay down chicken wire or wire mesh fencing and plant through it. Cutting a hole with wire clippers every time you plant a seedling sounds to me like a recipe for frustration and laceration. 

    I prefer to cover rows of seeds with row cover, a spun-bonded synthetic textile. I keep the fabric off the ground with rectangles of wire fencing with 2-inch openings. These are held down with small stakes. 

Peas under row cover

 I take the row cover off when the seeds sprout. I can remove the fencing when the seedlings have several leaves or let it remain to deter digging all summer. 

    I have to admit that this approach adds extra time and work to the job of starting the vegetable garden in spring. It does increase the chance that squirrels will leave the seedlings in peace.

    Protecting young plants in pots is even more complicated. This spring I’ve potted strawberry plants, a blueberry bush, a patio tomato, a bush cucumber, and two eggplant seedlings. I’ve planted radish and lettuce seeds in shallow containers. The question is how to keep these plants safe, short of standing guard all day. Past experience warns that they have little chance of surviving or producing without a barrier to keep squirrels out.

    I covered the little blueberry bush with a chicken wire cloche I bought from Gardeners Supply. 

Chicken wire cloche: adorable but pricey

Glass cloches were originally invented as mini-greenhouses, providing a warm, moist environment to encourage individual plants to grow. This one is just a barrier to keep marauders out. It’s not cheap at $25 plus shipping, otherwise I’d purchase a fleet of them. 
   
    After squirrels started digging in the other containers, I covered the pots with window screen or wire mesh or laid cut pieces of these around the plants on the soil surface, holding them down with small stakes or tomato cages. Still the squirrels find ways around my barriers. They never give up!

A squirrel found a way past the protective screening and threw mulch out of this tomato's pot

Less is more

Happy New Year! Amy Andrychowicz advises in the Savvy Gardening Newsletter that gardeners write “garden reflections” at the end of each year, documenting what went well and badly in this year’s garden and what can be improved next year. Here are some of mine:

    What went well? A lot that wasn’t in my control. We got plenty of rain! That kept the garden lush and flourishing. 

Rain made everything grow

    Also good was that the destructive nonnative winter moth dwindled my area. Tachinid flies (Cyzenis albicans) released by UMass professor Joe Elkinton are killing winter moth larvae. I counted three or four moths at the front porch lights this fall, nothing like the clouds of them we’ve seen in previous years. With so few parent moths, I predict few caterpillars will show up next spring to defoliate and weaken our trees.

There should be less winter moth damage next year

  
    Thanks to a much-abbreviated work schedule, I was in the garden most days all season. That gave me a chance to start addressing a list of dozens of tasks and projects I’d put off over the past decade. 

    This year I got to tear out a big patch of lawn and replace it with new perennials, mostly native species. It doesn’t look like much yet, with little plants surrounded by wide stretches of mulch. In three years when it’s filled in, I’m expecting a lush habitat for birds and native insects, as well as a pretty sight from the back of the house and the deck.

With luck, these little plants will grow wide and tall

    Restricting my container choices to neonicotinoid-free plants also turned out well, better than I’d expected. Maybe a smaller palette of choices prevented over-complicated compositions.

Simpler container combinations did better

    What didn’t go so well? Despite the plentiful rain, my vegetable garden didn’t produce a lot. Two problems stick out. First, I planted intensively with not much space between plants and rows because I’ve got so little sunny ground. That meant overcrowded plants didn’t get all the sun they needed. I didn’t leave enough space for paths, so while trying to spring lightly in and out of the beds, I stepped too close and packed down soil where roots were trying to grow.

Tight quarters in the vegetable garden

    This was the year I noticed my trees were crowded too, bent out of shape by competing to reach the light. That’s because of mistakes I made twenty years ago planting them too close together, like those vegetables. Having done that, I could have pruned more aggressively than I did. Back when the trees were young, I was afraid I’d kill them if I cut back their young branches to direct their growth. Now I know better.

Cramped trees

    The takeaway? Less is more. Make the hard choices and plant what I really have room for. Plan for the full-grown size, whether of 12-inch-tall bean plants or trees that will reach 60 feet. Failing that, don’t be too sentimental to thin out the extras when it’s time. Will I live by this insight and refrain from overcrowding the new perennial bed? Time will tell.

Pollinator-safe container plantings--do they work?

This spring I refrained from filling my shopping cart with brightly-flowering annuals at my favorite garden center. It felt like a deprivation, but I was trying to avoid bringing home plants treated with pollinator-killing neonicotinoid insecticides. 

What I aspire to--the pollinator garden at Locust Grove in Poughkeepsie

This meant changing my approach to container plantings. Now in August the garden is quiet, but the containers are coming into full bloom. It’s a good time to assess how the new approach worked out.

    I’d fallen into a routine of filling large containers with a combination of tender perennials and annuals from the garden center. 
 

     I carry warm-climate perennials, cannas, elephant ears, dahlias, and a favorite salvia, through the winter by storing them in the basement. Since most of my containers stand in full or part shade, I’d been adding shade-tolerant long-blooming annuals such as impatiens, browallia, torenia and coleus. 

Browallia blooms in shade

I liked the results, but truth to tell, the combinations hadn’t varied much in years. It was high time for a change.

    This year I followed Patricia McGinnis’ suggestion to “shop” in my own garden for perennials to use in the pots. I also found three places in Massachusetts to buy plants that haven’t been sprayed with pesticides: Thomson’s Garden Center in Salem, Allandale Farm in Chestnut Hill, and the horticulture program at a local school, Learning Prep School in Newton. 

Here’s how my containers turned out:

I surrounded Canna ‘Bengal Tiger’ with anise-scented sage (Salvia guaranitica), which just recently opened its deep blue flowers. 

There aren't many flowers as blue as this salvia's

A few marigolds added as fillers have bloomed continuously, adding a bright touch.

Neonic-free marigolds add a pop of color

    My favorite this year is a combination of another canna with an ornamental grass, name unknown, that I bought at Learning Prep. From the flowers (those wispy stalks at the top), I suspect it may be a reed grass (Calamagrostis).

A mystery grass turned out to be a good collaborator

Golden creeping jenny (Lysimachia nummularia ‘Aurea’) is adding a je ne sais quoi as a “spiller” falling over the edge of the pot. Heaven knows there’s plenty of this groundcover in the garden; it’s famous for its imperialistic tendencies.

    In shade, the giant leaves of elephant ears provide bulky focal points. To their pots I’ve added a purple-leaved heuchera for some contrast and offspring from an angel-wing begonia I bought last year that will offer pale pink flowers as the weather cools. 

Contrasting leaf colors and forms complement elephant ears

I doubt the begonia is neonic-free, but I couldn’t bear to throw it away. Japanese painted fern (Athyrium niponicum var. pictum) pops up anywhere shady in the garden. Not surprisingly, it’s willing to collaborate with elephant ears.

Japanese painted fern is an adaptable shade-lover

    Apple-blossom-pink geraniums are doing OK in part shade in the front yard, helping to cover up a not very decorative drain cover that we have to keep accessible. In Salem I found red coleus that’s growing well in a north-facing spot along the driveway.

Coleus without the pesticide spray

    The more I scrutinize the combinations in the pots, the more I can see ways I’d like them to be different. But overall, I’d say that for container plantings, there’s life without neonics.

Closing the loop

One of the principles of sustainable gardening is cycling of materials. This avoids the energy costs and environmental impacts that come with industrial production. Fully realized, this principle means aiming for a closed loop. In this vision of an ideal garden, no outside inputs would be needed. All energy, nutrients and materials would be generated and grown on-site.

Peonies thrive with leaf mulch and compost for topdressing

    This year I’m noticing that my garden has moved a short way along the spectrum toward that ideal. We’re far from sustaining ourselves through a permaculture system that imitates a natural ecosystem. But more and more I’m improving soil, mulching, and even filling seasonal planters with materials from my own yard.

Allium 'Purple Sensation' sends up more flowers each spring in good soil

    I’m relying more on compost to improve soil. Before I wrote my book, I thought organic gardeners were being unnecessarily pure by avoiding chemical fertilizer. After all, the nitrogen, phosphorus, and potassium are the same however they’re packaged, I thought. But I learned that manufacturing chemical fertilizer has a high environmental cost. I was also surprised to learn that it’s almost impossible to apply little enough of the synthetic stuff. By using it I was undoubtedly harming soil organisms with an over-abundance of nitrogen and adding to the phosphorus leaching into the local water table.

    Compost is free and good for the soil, it happens in two years whether I do any work on the piles of garden waste or not, and it does yield happy, healthy plants. My problem now is to generate enough compost for all the places I’d like to use it.

You can't have too much compost

    For mulch, over the past few years I’ve added arborist wood chips to my previous use of shredded or whole leaves. By using wood chips, I don’t have to buy bark mulch, which carries an energy cost for transportation. The leaves come from my lot or my neighbors’, so they can’t get any more local. The wood chips are the byproduct of tree work on local trees. Both make beautiful mulch. I like to use the leaves on perennial and vegetable beds. The wood chips are great for paths and for mulching around trees and shrubs.

Wood chips are great for paths and around shrubs

    This year many of my container plants are local too. I’ve just finished filling large pots for accents in the landscape. I combined tender perennials that winter in the basement with dispensable perennials I dug up around the garden. I like some large leaves, unusual leaf colors, and variegations to liven up the mostly medium-sized, medium green foliage. Time will tell whether these pots are interesting enough without the annual flowers I included in previous years. I left those out this year to avoid neonics.

Elephant ears with hellebores and a Japanese painted fern dug from the garden

     I’m not a purist. I don’t subscribe to “eating squirrel and crafting our own doorknobs,” in the words of Senator Elizabeth Warren. Just as she’s open to the right kind of international trade, I’m open to store-bought groceries and pesticide-free plants from the garden center. But as much as possible, in the garden I aspire to close the loop.
Onward and upward!

Paradigm shift for pots

In response to my question about which perennials to use as fillers in containers, Patricia McGinnis, an astute reader, wrote suggesting that bigroot geranium (Geranium macrorrhizum) would be a good choice. As she points out, it has attractive multi-lobed leaves that turn red in fall, and it spreads moderately.

Bigroot geranium this week

  Patricia’s email opened my eyes, and now I’m spotting any number of perennials I can use in containers to replace the impatiens and coleus I’ve been buying for years. The impetus for this search is to avoid nursery plants that have been sprayed with pollinator-lethal “neonics,” neonicotinoid insecticides that persist in plant tissues.

No point in attracting insects and then poisoning them

     In case you’re not familiar with the expression, “fillers” refers to a popular dictum for container designs: include “thrillers, fillers, and spillers.” Tender perennials with big bold leaves are my usual thrillers, and I like to balance them with mid-sized fillers. 

 

Canna with calibrocha filler last July. Lobelia had already melted in the heat.

Ideally I include something that blooms for a long season, but distinctive leaf shapes, colors or textures work too.

     Just about any vigorous perennial of low to moderate height could be a candidate, I see now. If a plant is spreading, I won’t feel bad about digging up a few rooted sections to use in pots. Some perennial clumps are due for dividing. That will be an opportunity to use a piece in a container. If a plant’s showing aggressive tendencies, that’s all the more reason to wrench some out, pop it into a pot, and let it die at the end of the season.

     In the moderately spreading category, I can picture using wild ginger (Asarum canadense), which has large matte green leaves that stay fresh-looking all summer. 

Wild ginger stays elegant through the summer

I could also use its imported cousin European ginger (Asarum europaeum). The shiny round subtly variegated leaves of this groundcover captivated me back when I started my garden. After very slowly increasing for 30 years, it’s starting to pop up in unexpected places, and I have enough to spare for potting. Maybe I could replant it in fall after a sojourn in a summer container.

European ginger this week

     Some hostas and hellebores that I planted too close to shrubs are now looking crowded and unhappy. They could provide some chunky mass to balance the giant leaves of cannas and elephant ears in pots.

A mature hellebore can be quite bulky

     As for groundcovers with invasive predilections, golden creeping Jenny (Lysimachia nummularia ‘Aurea’) is expanding wildly. Its near-yellow color could provide an interesting contrast, and it might drop stems gracefully over the side of a container.

Golden creeping jenny: don't be fooled, there's no stopping it.

     People often stick something with thin, strap-like leaves, such as a cordyline or an ornamental grass, in the center of a pot as a vertical element. 

Cordyline for verticality--photo by Daryl Mitchell

Perhaps I could draft smooth Solomon’s seal (Polygonatum biflorum) for this role. It too has taken over a lot of real estate in shady sections of my garden.

Two species of Solomon's seal sending up their shoots

     I can’t wait to try some of these ideas when I fill my containers in May. I bet I’ll see more options as perennials continue to emerge in the interim. Thanks, Patricia!

Ah, April! Yellow trout lily (Erythonium americanum)

Seeds of change

Now is the time for what Steve calls the “hot stove league.” In baseball, that’s sharing happy visions of your team’s coming season. In gardening, it’s paging through seed catalogs full of beautiful pictures of vegetables and flowers. The photographers and graphic designers for these alluring publications can make even a humble cabbage or carrot look like a must-buy.

    This year I’m planning a new direction for seed buying. I’m going organic. I’d never thought it was important to start with organically produced seeds. I was not going to apply pesticides to my seedlings, so why did it matter? 

     Now I’m aware that commercial seeds may be treated with neonicotinoid pesticides that could be stored in plant tissues and kill pollinators all summer long. That’s motivated me to put aside my favorite catalog purveyors in favor of seed houses that use organic methods.

For the pollinators' sake I'll plant organic seeds

    For my insectary garden, I’m going to start cosmos, celosia, monkey flower, sunflowers, and black-eyed susans from seed. For cutting, I’ll add zinnias. For growing in containers, I usually buy coleus, torenia, browallia, impatiens, and other long-blooming annuals that catch my fancy. I’m less familiar with starting these at home, but if I begin early and give the seedlings reliable attention, I’m hopeful that I can do it.

Monkey plant (Mimulus guttatus) offers bees early browsing

   
     This year I’ll also have time for succession planting. That’s planting new rounds of favorite vegetables every couple of weeks, avoiding the usual boom and bust pattern of my vegetable garden. By frequently planting very short rows of lettuce, sugar snap peas, and green beans, I hope to enjoy these vegetables over longer periods and avoid wasting produce that’s too plentiful for our household of two to eat. 

Can I spread out my basil crop by planting a little at a time?

     After all, what’s sustainable about ordering seeds that are shipped from afar, starting them under lights, and watering them with purified drinking water, only to leave them un-harvested and then throw them on the compost pile? I’m sorry to say that’s been my pattern in past years.

    To get a jump on the growing season, I’ll plant seeds indoors using Organic Mechanics peat-free seed-starting mix or my own non-peat potting blend, both containing coir (coconut fiber). I mix four parts potting mix with one part warm water and fill the cells of seedling six-packs I’ve saved from last year’s purchases. 

Waste not, want not--reusing six-packs from last year

I poke a hole in the mix with a pencil and plant three seeds in each cell. The labeled packs fit into trays filled with capillary matting—that’s spongy synthetic material that holds water to keep the potting mix moist from below.

     I wrap the trays in clear plastic (old dry-cleaning bags) and set them under grow lights.

African violets under the grow lights

     Until they germinate, the most desirable seeds may get bottom heat from a thermostatically controlled mat that fits in the bottom of the tray. 

Capillary matting lies on top of the heating mat

This gives them their start. Most of the seeds do germinate, especially if they’re new, not saved from previous years. Then it’s up to me to help the little plants grow bigger until planting time.

Home-grown cucumbers are worth the effort