My book and web site

Check out my book, The Sustainable-Enough Garden, available on Amazon, and the book's web site at www.thesustainable-enoughgarden.com. See more plant photos on Instagram.

Sunday, October 15, 2017

Nadia, my garden companion

Our dog Nadia died August 31. I miss her for so many reasons. For one, she was my gardening companion.

Nadia

    Nadia was a German shepherd mix who was 10 months old when she came into our lives in March 2002. At that awkward age, she was full of nervous energy, dashing around the house and trying to understand her new environment. She’d been sent back to the shelter by her first family, who said their children hadn’t kept a promise to take care of her.


    Nadia seemed to have had a good life before her four scary days back in the shelter. She liked humans and knew how to live with them. Our family of four went to Jamaica Plain to meet her and brought her home in our Subaru wagon. We imagined she’d stay in the far back while we sat in the seats. Instead, she leapt into the back seat and then the front to nuzzle us excitedly.


She liked to sit up front
 
    Once we got home, she explored the backyard. She loved to play tag but couldn’t see the point of retrieving anything. She buried bones in the compost piles. She designated a digging spot next to the side porch, where she excavated a hole three feet deep. I always imagined she was chasing a chipmunk that was desperately extending its burrow a few inches ahead of her. 


    We fell into a routine: three walks per day, including a visit to a park where she could go off-leash. That meant I got to know some beautiful conservation land at all seasons. As she enjoyed the scents and greeted the other dogs, I had a chance to observe the landscape around us. My sustainable gardening approach was born partly from that daily time outdoors.


Sampling the breeze at the dog park

    Although our yard was completely enclosed by fences, I think Nadia was just humoring us by staying inside them. One day she left the dog park without me when two big wolfhounds frightened her. I searched frantically. When I got home, she was inside the fenced yard, and the gate was closed. We never found out how she got inside.


    While I gardened, Nadia kept me company, lying on the porch surveying her domain or strolling around the yard, occasionally checking on my progress. 


Nadia helps with a study session

Rabbits frightened her, but she loudly repelled any dogs or cats attempting to breach our perimeter. At first the sight of me digging would inspire an irresistible desire to join in. As she got older and calmer, I was able to persuade her that I’d rather she didn’t help.

    Nadia enjoyed zestful good health until age 15. Then she started to slow down and developed medical problems that afflict older dogs. In her last few months, she had little appetite and lost 15 pounds. It was so sad to see our old friend confused, anxious and uncomfortable. Now I picture her young again, playing in Elysian fields. Her spirit is still very much with us. 


 

Sunday, October 8, 2017

The pawpaw patch

 A few Octobers ago, my next-door neighbor asked one morning whether I’d heard cats fighting in the backyard the night before. He’d been kept awake by animals screaming near the fence that divides our properties. I went to check out the area and found broken branches in a pawpaw tree. My theory is that raccoons were fighting over the ripe pawpaw fruit.

Pawpaws--raccoons love them

    Pawpaw (Asimina triloba) is America’s largest native fruit. I highly recommend this tree for its decorative appearance as well as its fruit! I planted a young sapling about ten years ago. By sending out root suckers, it’s grown into a patch about 12 feet wide and tall. The tree’s large leaves give it a tropical look.


Pawpaw trees add zing to the landscape with their large leaves

    Until the “fighting cats” episode, I didn’t realize the tree was bearing fruit. That day I noticed some yellow fruits that had fallen to the ground. Looking up, I saw clusters of green ones on the branches. 


    Pawpaw fruits look a bit like mangoes. Mine don’t get more than four inches long. The smooth skin covers yellow custard-like flesh surrounding up to a dozen large seeds shaped like lima beans. 


Pawpaw seeds

The fruit’s delectable taste is somewhere between banana and mango. 

 
Pawpaw fruit is a seasonal treat

     Birds, opossums, and raccoons enjoy pawpaw fruit, and they’re great at sensing when it’s ripe. That means I have to be on my toes to share in the harvest. During last year’s drought I got none. I suspect that thirsty animals grabbed the pawpaws as soon as they were edible. This year I’ve snagged a few ripe ones from the ground under the tree.


Ripe pawpaws

    Most people in the Northeast haven’t encountered pawpaws except in that old song, “Way Down Yonder in the Pawpaw Patch.” The reason for the lyric “Picking up pawpaws, puttin’ ‘em in your pocket” is that the fruit isn’t ready to eat until it falls to the ground. Eaten too soon, it has a mouth-puckering taste like under-ripe kiwi fruit. 


     We don’t find pawpaws at Whole Foods yet because the ripe fruit doesn’t last long enough to ship to market. Kentucky State University’s Cooperative Extension Program is working on this; they’ve made pawpaw research their specialty. Their nutritional analysis puts pawpaws’ antioxidant content equal to cranberries’.

    Pawpaw is a tree of the continental interior. It likes humid summers and dislikes coastal breezes. Native Americans are credited with having spread pawpaws from Canada to the Gulf Coast. Washington and Jefferson enjoyed the fruit, and it nourished the Lewis and Clark expedition when they ran out of food.

 
"Hungry? Try the pawpaws over there."

    The National Park Service reports that pawpaws are the most common saplings in their forest monitoring plots around Washington D.C. This is partly because deer don’t like pawpaw leaves, which contain nasty-tasting insecticidal chemicals called acetogenins. When other trees are decimated by overpopulated herds of hungry deer, the pawpaws are left to soak up the sunlight. 

One deer is charming, thousands defoliate the landscape--photo merrilyanne

     Suppressing wildfires also favors pawpaws, which are less fire-adapted than other trees. Someday we may see pawpaws where we used to see maples and oaks.

Sunday, October 1, 2017

Not all the perfumes of Arabia can wash this little leaf clean

At a meeting of the Wayland Garden Club last month, a gardener reported tar spot fungus on her Norway maple leaves and concluded that this meant she had to remove all the leaves from her property. She reasoned that they couldn’t be used for compost or mulch for fear of spreading the fungus to her lawn and garden. 

Are leaves infected with fungus harmful to other plants?

    You too may have noticed that Norway maple leaves have developed black spots, turned brown and started to fall much earlier than usual. 



Black tar spots on Norway maple leaves

You could imagine that the trees are dying. Fortunately or unfortunately, the fungal infection is just cosmetic. This year’s very wet spring gave a boost to various fungi, including those that cause both tar spot and anthracnose, another fungal condition that causes leaves to brown and drop off, but the trees will leaf out again next spring. 

This Norway maple's leaves have prematurely turned brown and started to drop off

You don’t have to protect other plants from contact with the infected leaves.

    I say fortunately or unfortunately because I’m ambivalent about harm to the Norway maples that line our streets. Like many cities, mine used to favor tall, graceful elms as street trees. 


American elms in Central park

Dutch elm disease, another much more lethal fungal disorder originally from Asia, arrived in New England in 1928 and burst out of control during World War II, when attention to containing its spread was diverted to war efforts. To replace the dying elms, the cities planted Norway maples. They were tough enough to thrive in urban conditions. What could go wrong?     

     Eighty years later, we’re dealing with the consequences of this decision. Free of the competitors they faced in their native range in Europe and western Asia, these trees have become invasive in North America. 

Norway maple in flower, its prettiest time-photo Daniel Case

Since 2009 it’s been illegal to sell or plant them in Massachusetts.

    When we moved into our house in 1985, we had Norway maples as street trees (still present), large specimens stood in neighbors’ yards, and a volunteer thicket of them grew behind the back fence. Now there are fewer Norway maples around us, but I still pull hundreds of their seedlings from my planting beds every spring.


Norway maple seedlings: there are always more coming


    Norway maple has long been my most hated tree. I’ve often wondered how I’d feel if a pest finally came along that could kill them all. The Asian long-horned beetle, which enjoys munching maples, looked like a good candidate. 


Asian long-horned beetles on a maple. This menace hasn't reached my yard yet-photo USDA.

I admit it’s a thrill to see the tar spots inflicting Norway maples and bypassing red maples, a near relative that is native, non-invasive, and less susceptible to the fungus.

Red maple leaves free of fungus


    Call me a wimp, but I can’t wish all those Norway maples dead. They’re a menace, but they’re still providing us with “environmental services” such as sequestering carbon and cooling and cleaning the air. Their dense shade is a bane for gardeners but very welcome to drivers seeking parking places on hot days. Let’s say they have the defects of their qualities. They’re tough, hardy, and good at reproduction. Can we, who planted them, hold them responsible?


Winged maple seeds are called samaras
 

Sunday, September 24, 2017

A fair trade

Last weekend I attended a plant swap at New England Wild Flower Society. The society invited members to dig up some plants we could spare and bring them to trade with fellow gardeners. This turned out to be a lot of fun.


NEWFS's Garden in the Woods is a fabulous resource in Framingham, MA

    Each participant brought at least one plant, natives preferred but not required. We were each assigned a group number, 1 through 4. The offerings were varied, from garden favorites quite familiar to me to native plants for special locations such as swampy areas. When everyone had arrived and our group number was called, we dashed to the plant tables and each chose one plant. We took turns choosing until the plants were gone.


    I’d brought two wild gingers (Asarum canadense), two white-flowering phlox (Phlox maculatum ‘David’), a white bleeding heart (Lamprocapnos spectabilis ‘Alba’), and a goldenrod (genus Solidago) whose forebears I grew from seed years ago. 


Phlox 'David" blooms in mid- to late summer

     As I placed my offerings on the tables, I realized I’d be embarrassed if nobody chose them—like not being picked at a dance. I was relieved that they all found homes by the last round. Next year I’ll pot some plants in spring so they’ll look more appealing for the swap at the end of the summer.

    I came home with eight plants: a beautiful purple heuchera, a switchgrass (Panicum virgatum), a foxglove, a blue false indigo (Baptisia australis), two blazing stars (Liatris ligulistylis), a showy goldenrod (Solidago speciosa) and an Allegheny monkey flower (Mimulus ringens).


This well-grown heuchera was a prize

Besides a fun “shopping” experience and a chance to meet like-minded gardeners, the swap met two sustainability goals for me. First, I could be sure that none of my fellow NEWFS members had been spraying their plants with neonicotinoid insecticides before bringing them to the exchange. Neonics persist for a long time, but my hope was that these plants were either seedlings from the gardeners’ original plants, or they’d been around long enough to have outlived any pesticides they might have encountered at a nursery when they were young.


Native plant enthusiasts know not to poison pollinators with neonics

    Second, a swap like this gets around the carbon cost of garden center plants. Annuals and perennials we buy locally zip around the globe before they end up in our shopping carts. Growers may buy seeds from importers who source seed all over the world. They use tissue culture products imported from South Africa, Holland, Turkey, and Poland (tissue culture converts tiny pieces of plant tissue into large numbers of genetically identical plantlets). Large plantations in Costa Rica and Ecuador with space to maintain supplies of stock plants send unrooted cuttings for regional growers in the US to root and grow to saleable size.


Plants growing from tissue cultures-photo Daderot

    To produce high-volume annuals like petunias, breeders send cuttings to specialists at a rooting station, for mass production. A broker shopping on behalf of wholesalers or garden centers fills orders with rooted cuttings from multiple rooting stations.


    Unlike these international travelers, perennials from the plant swap really do come from the local area. And they’re free! A good deal all around.


This goldenrod grew up in my yard

Sunday, September 17, 2017

Hell and high water

Photos of Houston afflicted by Hurricane Harvey reminded us of the worst that stormwater can do. It’s been pointed out that Houston’s unrestrained development created a set-up for flooding.

Flooding in Houston

Developers have been building in flood plains and paving over wetlands and prairies, reducing the chance for rain to soak into the ground. Smarter urban planning could have lessened the catastrophic effects of the hurricane.


Wetlands around Houston used to absorb stormwater--photo by Daniel Ray


    Did you know that China is a leader in this environmental area? They’re developing “sponge cities,” engineering ways to keep rainwater for use by water-poor cities, rather than letting it run off.  Besides cutting down on impermeable paved surfaces, they’re collecting rainwater in ponds and tanks and circulating it into the cities’ water supplies, either for non-potable uses or purified as drinking water.


    I hope it never happens, but if we got 50 inches of rain (a year’s worth) in a few days, the amount that fell on Houston, we’d want to let it soak through every possible surface.




Our deck and stone path, wet but permeable

Even without a huge hurricane, it’s better to keep rainwater on your property, because if it rushes down the street, it carries pollutants with it into nearby waterways. Here are some ways we gardeners can make our yards more sponge-like.

•    Make hard surfaces permeable. This is probably the most important change you can make. For us, the driveway is the main impermeable surface. By replacing a section of our asphalt driveway with porous paving material, we’ve enabled water to soak into the ground. 


Water sinks into the darker porous paving

A nice-looking alternative is to make a driveway out of stones with spaces between them where water can soak in. 

Paving stones let water soak through


Spaces between the stones of our new walkway similarly allow water to reach the soil below.

•    Direct water where you want it to go. If you’re an enterprising digger, you can create swales—basically trenches--to send water to your garden beds or to low-lying areas, where it will gradually percolate into the soil. 


Bioretention swale in Seattle during a 100-year storm

David Del Porto, an environmental visionary who designed an eco-friendly house and landscape called the Urban Ark 30 years ago, told me he used this approach to direct rainwater from his roof to the right spots in his vegetable garden, obviating the need for irrigation with purified drinking water. 

•    Plant a rain garden. This is a shallow depression, ideally at the lowest area of your yard, where water can collect and filter into the soil. Plants in the rain garden will soak up water and help purify it. Heavy soils may need to be amended with sand or gravel to make them drain faster in the rain garden; our sandy soil drains fast already.


A rain garden in Leeds, MA--photo U.S. Air Force

I like to think that we designed a rain garden without meaning to, because the land slopes down from the fence lines, making the center of the yard a collecting site for rainwater. I’d still plant a rain garden if I had a place for it. It’s a great excuse for a new planting project.

Sunday, September 10, 2017

Gypsy moth: more complicated than you'd think

While waiting last week for my computer to return from urgent care, I contemplated a talk about biological controls by Joseph Elkinton, a professor of environmental conservation at the University of Massachusetts, that I heard last November. 

Gypsy moth caterpillar

    What Elkinton said about the history of gypsy moth in North America turns out to be unexpectedly relevant. We had a gypsy moth surge in 2016, and this year there has been significant defoliation by gypsy moth caterpillars, especially in southeastern Massachusetts.

Voracious gypsy moth caterpillars shred leaves

    A complicated web of factors influences the gypsy moth population. It all goes back to acorns.


    Gypsy moth (Lymantria dispar), native to Europe, was introduced to Medford, Massachusetts by Étienne Léopold Trouvelot, an astronomer dabbling in silk worm breeding. He thought he could cross the gypsy moths with native silk moths to produce silk in the US. The insects escaped from his home in the 1860s, and over 50 years they slowly established themselves in the wild. They’ve spread as far as Minnesota and North Carolina.


Life stages of the gypsy moth

    Elkinton explained that until 1989, gypsy moths experienced population outbreaks about every 10 years. Throughout the twentieth century, predator insects were introduced in hopes of controlling the gypsy moth population, but none did enough.


Predatory wasps kill caterpillars, but not enough

     Meanwhile, research into the ecology of the gypsy moth uncovered a system of natural controls. Robert Campbell of the US Forest Service found that the white-footed mouse was the most significant predator of the caterpillars, with birds less of a factor.

White-footed mouse, Peromyscus leucopus, in captivity

     Mouse populations rose and fell with the supply of their main food, acorns, which fluctuated with weather conditions. The mice couldn’t expand their population enough to control gypsy moth outbreaks, when caterpillar numbers spiked exponentially.

    Outbreaks were brought to an end by Nuclear Polyhedrosis Virus (NPV), which eventually killed up to 99 percent of the horde of larvae.


    This cycle continued until another accidental foreign introduction in 1989: Entomophaga maimaiga, a Japanese fungus. Infected by the fungus, gypsy moth caterpillars suddenly died all over southern New England.


    So with mice, viruses and fungi controlling its population, why is gypsy moth surging again? The levels of fungus are highest in wet years. Last year’s severe New England drought allowed the gypsy moth population to escape from its fungal control. This summer, caterpillars chomped foliage until June, when they started to die off. Caterpillars examined by Elkinton’s team showed a combination of viral and fungal infections. Wet weather had turned the tide.


    This means, thank heavens, that we don’t have to make the difficult decision whether to spray for gypsy moth.


    The future outlook for New England trees is mixed. Gypsy moths won’t die out completely, and our trees face a number of stresses from drought and other nonnative insect attacks. A tree can survive one defoliation, but repeated losses deplete its energy stores. Elkinton worries about major losses of native oaks, which the caterpillars particularly enjoy. Then what will happen to the white-footed mice?


 

Sunday, August 27, 2017

Squirreling away acorns for winter

Acorns are falling. I swept the deck yesterday afternoon, and by this morning a few dozen more acorns dotted the surface. They’re a sign that autumn isn’t far off, and for squirrels, they’re the start of the fall harvest.

Red oak acorns


    Gray squirrels are so much part of our suburban surroundings that we tend to overlook their activities. To remedy this, I opened North American Tree Squirrels, by biologists Michael Steele and John Koprowski. Steele and his colleagues and students designed clever experiments to elucidate the feeding behavior of squirrels they found on their campus at Wilkes University in Pennsylvania.



Eastern gray squirrel (Sciurus carolinensis)

    For gardeners who like oaks, it was good news that acorns can be half eaten and still germinate and produce seedlings. Steele noticed that in early fall, when acorns were plentiful and the weather was still warm, squirrels usually ate acorns of white oaks but cached red oak acorns for later. White oak acorns are programmed to germinate in the fall.


 
Squirrels may pretend to bury acorns in decoy locations


    The red oaks play a longer game. Their acorns contain higher levels of tannin, a nasty-tasting chemical that protects seeds from predators. They’ve evolved to germinate in spring after a necessary cold period. The researchers observed that later in the fall, squirrels started removing the acorn caps to eat just the tops of the red oak acorns, which contained more high-calorie lipids and less tannin. As winter set in, they were willing to eat the whole red oak acorn, tannin and all. Apparently like us, squirrels balance tastiness versus health factors when they choose food.


Health food or tasty treats? It depends on the time of year

    Do gray squirrels remember where they hide their acorns? It was long thought that they didn’t and had to sniff out buried acorns. Lucia Jacobs, then at Princeton University, showed through an ingenious experiment that squirrels found their own cached acorns more readily than those hidden by other squirrels, although others’ caches might be quite nearby. 


Squirrels remember where they hid their nuts--photo by Juraj Patekar

    As a directionally challenged navigator, I’m awed by squirrels’ ability to recover their hidden nuts. Scientists asked whether squirrels were just good at retracing their steps—I can usually do that—and were finding their caches that way. Or were they constructing a three-dimensional mental map that allowed them to locate their hidden acorns? 


    Another of Jacobs’ lab experiments confirmed the latter. If she trained squirrels to find a nut in a maze and then kept the nut in the same location but changed the way to get there, the squirrels still found the nut. They’d retained its location, not just the directions for getting there.


 


    Although squirrels recover most of the acorns they store, they do serve red oaks by dispersing their seeds. A study of white versus red oak seedlings found that most of the white oaks sprouted close to the parent trees, whereas red oak seedlings appeared three to six times farther from the mature trees, their acorns having been moved by squirrels and other animals. In this way, squirrels contribute to the development of our forests.


Sunday, August 20, 2017

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.