It seemed like a good idea at the time

             Four years ago when coyotes started eating small pets in our town, I launched my misadventure with a plastic closed composter. My advice: don’t waste your money on this type of bin.

            My motive was altruistic. Wildlife officials pointed out that coyotes are omnivores, quite willing to snack on carrot tops or apple cores on open compost piles. I didn’t want to invite predators to my block by putting out a coyote smorgasbord of fruit and vegetables. 

On the prowl for watermelon rinds

            In November 2011 I ordered a black plastic bin recommended by a Master Gardener I’d consulted. It was a wide, bottomless cylinder about 3 feet tall, tapering slightly toward the top, equipped with numerous air vents and a locking lid. 

My compost bin was not unlike this one

Throughout that mild winter, I dropped plant waste from the kitchen into the bin, covering the scraps with a layer of dry leaves or paper shreds to provide carbon and to keep the compost from being too wet.

            As soon as the weather warmed up that spring, something chewed a hole through the back of the plastic bin starting at one of the ventilation slits. The hole gradually enlarged to a rough-edged oval around 2 by 3 inches. So now I was feeding a small animal—could it be a chipmunk or a rat?   

I never saw the animal that gnawed a hole in the bin

            I tried to block the hole by fitting a broken flower pot against it inside the bin.  The intruder just enlarged the opening.  Meanwhile, the rate of decomposition inside the bin was unimpressive.  The top level of scraps gradually dropped, indicating some progress (or prodigious work by rodents), but I certainly wasn’t seeing any “black gold.”  After eighteen months with no apparent compost developing, I gave up and stopped adding to the bin.

            Two years after I’d started, I lifted the black cylinder off the pile, revealing an uninspiring mound of hard half-made compost studded with undecomposed egg shells. I pulled out the egg shells and buried them in the nearby open compost pile. I plunged my spade into the remaining lump, and that’s when I realized that the bottom 3 inches was a mat of roots. I should have lined the bottom of the bin with landscape fabric. 

            So after two years, I had about a half bushel of black, dry, partially decomposed food waste.  It didn’t look like it would attract animals, so I chopped it up and dumped it in a corner of the vegetable bed, hoping it would do some good next year.

            This was a far cry from bin manufacturers’ bold promises of finished compost in sixty days!  I threw the smaller parts of the plastic bin in the trash but couldn’t fit in the main cylinder. That would have to wait until the Public Works Department came to pick up large items.  Even getting rid of the bin was inconvenient. At least I hadn’t attracted any coyotes.

            Tune in next week for a cheaper way to keep food waste away from animals.

Great oaks from little acorns

I just learned that one out of 10,000 acorns grows into a mature oak tree. That’s not great reproductive success. A mature oak, fifty years old or more, produces thousands of acorns every year, up to 10,000 in a boom or mast year, which occurs every three to five years in red oaks. One reason that few acorns grow into adult oaks is that so many become food for wildlife.

            An eastern red oak (Quercus rubra) happens to be one of the keystone trees in my yard, more than 100 years old and standing close to the house. I used to resent its shade. 

This red oak, our tallest tree, is older than the house.

Now I see it not just as an individual but as a whole community, including a housing project and grocery store (or maybe a community-supported agriculture cooperative) for wildlife I want to support.

            At this time of year, acorns are starting to ping off the metal roof of the garage, and the ground under the tree is littered with them, making for a lumpy surface underfoot. 

Red oak acorns

Red oak acorns take two growing seasons to mature, so the ones on the ground today sprouted two springs ago. White oak acorns (Quercus alba), the other type common in my area, develop in a year.

            At least ninety-six North American animals feed on oaks, eating acorns, twigs, buds or bark. White oak acorns are sweeter than those of red oaks, and they get gobbled up by squirrels and other creatures as they fall. Red oak acorns are bitter, because they contain more tannin. They retain their food value through the winter; animals can eat them in spring when all the tasty white oak acorns are gone.

            The oaks benefit from providing nuts that animals want to eat. Researchers observing jays found that each bird transported and cached around 110 acorns per day. The acorns the jays hid—they prefer to bury them in soft, moist soil—were more likely to germinate than acorns that fell under the tree. Squirrels dig holes in my garden to hide acorns, and some of them do sprout, although they’re far outnumbered by Norway maple seedlings.

Two white oak seedlings in a neighbor's juniper bed

            Besides feeding the birds and mammals that visit my yard and eat acorns—jays, crows, wild turkeys, squirrels, raccoons, chipmunks, rabbits and opossums—oaks are the best tree hosts for native insects I’d like to attract. Oaks support 534 butterfly and moth species, and there are 600 insect species that use oaks as their only host plants.

            As our red oak loses its lower limbs with age, its shade at garden level becomes more diffuse. In addition to all the ecological services it provides— improving air quality, modulating temperature, and sequestering carbon, to name a few--it’s now supporting a 30-foot climbing hydrangea (Hydrangea anomala subsp. petiolaris). I’ve learned to think of the giant oak as an essential part of my garden’s habitat.

The base of the red oak is hidden by the climbing hydrangea clinging to its bark.

It takes a plant community

Sometimes it feels like we’ll never get ahead of opportunistic nonnative plants. Especially with woody plants like Japanese knotweed (Fallopia japonica), it seems once they’re in your garden, you may never see the end of them. 

            In his book Gaia’s Garden, Toby Hemenway argues that opportunistic plants grow where we’ve given them an opening in disturbed ground and will naturally die off as stable plant communities take over (Hemenway prefers the term opportunistic to invasive, which he considers too emotionally loaded. I’m using his terminology). This is a nice idea, but considering how much Japanese knotweed I see in the course of a week’s driving, I wondered how likely Hemenway’s scenario was in my area.

This Japanese knotweed's underground rhizomes could be as much as 60 feet long. It propagates by seeds but is also capable of regenerating from root or stem fragments.

          
          This week I was pruning dead branches out of a dwarf mugo pine, (Pinus mugo 'Paul's Dwarf') planted eighteen years ago that is now partially shaded by a nearby magnolia. It occurred to me that this could be an example of Hemenway’s point. The branches that were in full shade were dead, with clinging brown needles, whereas the side of the little tree that was still in sun was looking good and producing green needles. I hadn’t shaded out this pine on purpose, I’d just failed to imagine how big the two trees were going to grow and planted them too close together.

Mugo pine reaching for sunlight outside the shade of a taller magnolia

            If the magnolia had cast its shade over an unwanted shrub like Japanese knotweed, I suppose it too would have dwindled. The problem, Hemenway points out, is that suburban landscapes, even our parks, offer so many sunny edges that favor fast-growing plants like the knotweed.

            Of course, shade isn’t the only condition that discourages opportunistic plants. The goal is to replace a plant that you don’t want with one, or ideally some, that you do. If you just remove the offender, you leave open soil for opportunists to take over again. Growing together, a group of native plants that have evolved to cooperate can succeed in grabbing the resources an opportunist needs to survive, not just sunlight but also water, soil nutrients, and room to grow.

            While I wait for my growing collection of native plants to knit themselves into anti-opportunist communities, I’m still cutting a couple of knotweeds at the fence line to the ground every couple of weeks, hoping they’ll eventually run out of stored energy and give up.

I cut it down, but this deceptively frail-looking Japanese knotweed, center, keeps coming back up. Will encroaching smooth Solomon's seal help to curb its growth?

             

Seed capital

One gardener’s spectabilis is another’s horribilis. When flowering plants make viable seeds that spread around the garden to germinate next year, you may think it’s a blessing or a curse.

            Remember that primary school unit about how seeds travel? I have examples of all the strategies in my garden this month, from burrs to wind-catching silky parachutes to fruits that co-opt birds to carry the seed to new locations. We plant for flowers, but the plants’ goal is to pass on their genes to another generation.

            Usually I like having the surprise of little seedlings popping up here and there in spring. This is the time of year when I have to decide who shall live and who shall die (or at least reproduce)--which seedheads to leave alone and which to clip out before they can drop their seeds.

            Some of my favorite purchases have turned out to be self-seeders, especially white bleeding heart (Dicentra spectabilis ‘Alba’). Spectabilis translates as “worth looking at,” and that perfectly describes the glowing heart-shaped flowers when they bloom in my May garden. 

White bleeding heart--worth looking at

Other enthusiastic self-seeders I enjoy include columbine (various species of Aquilegia), dwarf goatsbeard (Aruncus aethusifolius), and forget-me-not (several species of Myosotis). When these sprout in unexpected locations, I let some grow, pull some out, move others to better spots, and pot a few to give away.   

Columbines sometimes cross-breed, changing flower colors in the offspring, but this dark purple has stayed true.

             Then there’s tall verbena, Verbena bonariensis, whose seedlings are legion in my vegetable beds. This odd South American self-seeder sends up a single 3- to 4-foot stem with a small lilac purple compound flower at the top. It’s a prolific producer of seeds considered invasive in the South, but not in Massachusetts yet. I bought some from a mail order nursery ten years ago, and new volunteers sprout every year.

            I keep some of the seedlings because migrating monarch butterflies used to touch down on the flowers to refuel. I haven’t seen the monarchs for a couple of years, perhaps because their population has declined drastically due to habitat loss and the use of herbicides that eradicate the milkweed their caterpillars need for food. 

Instead of monarchs, nonnative cabbage white butterflies (Pieris rapae) are visiting the tall verbena this year.

I’m growing some milkweed now in hopes the monarchs will return.

Seeds of swamp milkweed (Asclepias incarnata) getting ready to float on silky floss

            Because I patrol the beds each growing season deciding which seedlings to coddle, which to tear out and which to relocate, I maintain something close to the balance I prefer. Like ground covers that can spread unmanageably, self-seeders can be so effective that they take over the garden. At least with the self-seeders, I can say no to future spread with diligent dead-heading in late summer and fall, removing spent flowers before they set seed.

A butterfly is born!

An eastern black swallowtail butterfly, Papilio polyxenes asterius, has emerged on my potted parsley! This summer has been very encouraging. Apparently if you plant what native insects want, they'll come.

     I planted some parsley in the vegetable garden and some in a big pot on the deck, hoping to create reproductive space for this butterfly, as well to harvest some garnish. I noticed the mature larva, a large, elegant caterpillar, two week ago.

It transformed into a pupa soon afterward.

 

When I got back from vacation, it had hatched.

I saw what could have been the hatchling flying around the garden today. It declined to stay still long enough to have its picture taken, but here's a file photo showing what it looked like:

Adult female. Photograph by Donald Hall, University of Florida.