Green thoughts in a gray landscape

During a Christmas week visit to New York, I noticed some ways city dwellers bring greenery into their surroundings. People crave vegetation. There were shrubs toughing it out in pots in the front areaways of brownstones, big planters in front of skyscrapers, window boxes, even fake vegetation, such as this plastic sheet printed to make a Brooklyn chain link fence look like a wall of ivy, 

Nice try

and this blanket of artificial turf masking a utility area on Roosevelt Island.

Something must be really unsightly

    I sure miss greenery during the shortest days. House plants help. In addition to cleaning the air and converting the carbon dioxide we exhale into extra oxygen in the house, indoor plants have many demonstrated psychological benefits. They reportedly promote calm, attentiveness and creativity and increase productivity. I’d just say they make winter less depressing and bring life to sterile man-made environments. We weren’t made to live without plants.

Houseplants remind us of greenery to come

    There’s an often-mentioned theory that the reason we surround our houses with lawns is that early humans felt safer in grasslands where they could spot approaching predators before they pounced. This strikes me as possible but completely unproveable, as are many products of the school of thought that attributes the behavior and psychology of modern-day human beings to hunter-gatherer culture earlier in our evolution.

If only he'd had a lawn!-Reconstruction by Mauricio Anton

    Now that the sabre-toothed tigers are gone, we can skip a lot of that lawn and replace it with a more diverse landscape. Even video game designers have gotten past the ubiquitous veldt, endowing their imagined landscapes with lush, region-specific vegetation. That’s what I’m hoping for in my yard. In winter, I’m glad that I planted lots of evergreen shrubs and trees that offer splashes of color in the otherwise drab view from the back of the house. They also provide shelter for wildlife, confirmed as birds pop in and out of the branches.

At least there's something in the yard that's not brown or gray

    As I survey the scene from the back windows, I’m hoping that in addition to the conifers, the thick layer of fall leaves I piled on the beds this fall is also doing good for creatures in the yard. I picture insects burrowed into the leaf litter and sleeping in the flower stalks I left standing. The theory is that lots of beneficial insects will emerge in spring ready to start their work as predators keeping leaf-eating insect populations in balance.

Beneficial lacewing prepares for winter

    Last year in late winter we went south to New Orleans, Memphis and Nashville seeking an earlier spring. We did see some green leaves, 

New Orleans has ferns that don't grow in New England

but I learned what I was really yearning for was the day-by-day unfolding of spring at home. 

     One of the pleasures of tending the same garden space over the years is adding to your store of observations about how it changes through the seasons. I know that winter doesn’t mean an end to all natural processes, they’re just happening where I can’t see them. Roots are still storing nutrients, ready to send them up into new growth in spring. Until then, I’ll crave green things.

Come back soon!

Conventional wisdom that's wrong

With fall garden work in my future—spreading compost, chopping leaves for mulch, and generally preparing for the cold months ahead—I’m glad to learn that some conventional gardening wisdom turns out to be false. 

Time to prepare the garden for winter

My heroine Linda Chalker-Scott, professor of urban horticulture at Washington State University, has the research to prove it. Here are three myths we can forget about:

Nitrogen-sucking mulch
It used to be an article of faith that high-carbon mulches such as the ones I use—shredded leaves and wood chips—would use up nitrogen in the soil in their decomposition process, thereby leaving plants short of this important nutrient. 

Does wood chip mulch cause nitrogen deficiency?

Chalker-Scott found that it doesn’t happen. So we can go on spreading organic mulch without adding high-nitrogen chemical fertilizer to make up for the imagined loss. 

     There may be a narrow zone of nutrient deficiency just at the mulch-soil interface. That’s actually a good thing, because it’s where young weeds would try to get started. The lack of nitrogen will help keep them from succeeding. It doesn’t hamper the growth of plants with established root systems, though, because they feed further down under the soil surface.

Acidifying soil
Another shibboleth is the proposition that adding oak leaves or pine needles to compost or using them as mulch will acidify soil. Soil is not as simple as we used to think. Adding acidic components to soil is not like putting vinegar on your salad. The soil has a buffering system that prevents swings in its pH. People who mulch with oak leaves year after year see no change in their soil’s pH, and pine needles, widely used in the Southeast, make some of the best mulch there is. 

Pine needles make great mulch

If you really want acid soil, you have to add chemicals such as ammonium sulfate, which only works temporarily. Here in Massachusetts our soil is naturally acid, so we don’t need to add chemicals to grow acid-loving plants like blueberries and rhododendrons.

Winter wraps
Some people in my town wrap their broadleaf evergreen shrubs in burlap during the winter. This is intended to prevent drying caused by sun and cold winter winds. There’s some justification for this; leaves can indeed be killed when they lose moisture to evaporation and the frozen ground offers no replacement. 

     You may also see ads for anti-dessicants sprays that purport to prevent evaporation from leaves. Chalker-Scott found that using these materials is more likely to prevent your plant from taking in carbon dioxide, photosynthesizing, and avoiding overheating. 

    To my mind, wrapping rhododendrons and boxwood shrubs in burlap cancels the benefits of growing them in the first place. One of my main reasons for planting evergreen shrubs is the chance to enjoy their green leaves in the winter landscape.

Greenery is welcome in winter

     It turns out you can protect your shrubs best by making sure they’ve had enough water before winter starts and by mulching generously to hold that moisture in the soil. That way they can lose some water without ill effects.