Green Grows the Grass


Winter dormancy is settling in on lawns almost everywhere but the pampered ones in National Football League stadiums. The groundskeepers who maintain stadium turf have an especially difficult job this time of year because they are staving off the natural tendency of grass to retreat into dormancy and turn brown and stiff as winter approaches. Not only does that look unappealing on television, it is difficult for the players who have to compete on it. If the ground becomes frozen hard, natural turf can be as dangerous to players as the old artificial turf fields which had insufficient cushioning beneath them.

Preparing the pitch at Stamford Bridge
Preparing the pitch with grow lights at Stamford Bridge, London;
own work by TheBlues

Modern NFL stadium natural turf stays green into December and January because groundskeepers take measures to prolong its growing season, from heating systems underneath to grow lights overhead. They effectively keep the grass in a condition most homeowners have not seen in their lawns since September. The “frozen tundra” of Lambeau Field in Green Bay, Wisconsin, is a memorable phrase evocative of the hard knocks of winter football outdoors in the upper Midwest, but it hardly applies any longer to the actual playing conditions considering modern turf management techniques.

For the average homeowner who looks out at a brown lawn throughout the winter (when it’s not covered in snow), the remedy lies not in trying to replicate the green turf of NFL stadiums. That would require an enormous input of money, time, and effort equivalent to what an NFL franchise invests, albeit considerably scaled down. Better to let the grass go to sleep for winter, but to tuck it in with some lime, some compost, maybe a light application of preferably organic fertilizer, and then a last mowing at a short setting to mulch the last of the fallen tree leaves. For the rest of December and January it’s time to settle into a comfortable chair in the warmth indoors and watch the football games on TV play out on the greener grass of early fall, maybe with snow falling on it for added dramatic effect.
– Izzy

View of Lambeau Field
View of Lambeau Field in Green Bay, Wisconsin;
own work by JL1Row


Careful with that Axe (at last)

There is no time of year when you absolutely should not prune trees and shrubs, particularly when it comes to pruning for the safety of people and property or for the health of the plant. There are better and worse times, however, to paraphrase Charles Dickens from the beginning of “A Tale of Two Cities.”

BLM Botany 03 (6871307185)
Photo by Flickr user Albert Herring

Late summer and early fall is the worst time to prune, and late winter and early spring is the best time. The reason for leaving trees and shrubs alone from August through October (the timing changes depending on the first frost date where you live) is that during frost-free weather pruning encourages new growth, yet the first frost is not far off. If the plant puts out tender new growth at this time of year, a frost may damage or kill the new growth, wasting the the energy the plant just put into top growth at a time when it should be drawing its energy toward its roots in preparation for winter dormancy.

For most trees and shrubs, February through April is the best time for pruning because the plant is dormant, yet it will break dormancy soon and the flush of energy to its top growth will help heal the pruning cuts and cover them. There are exceptions to this rule, and a maple tree is one. Any maple tree produces copious sap in late winter and early spring, not just the sugar maple from which we derive maple syrup. Wounding – and yes, a pruning cut can amount to just that – a maple at that time of year results in excessive bleeding of sap, weakening it. It is better to prune a maple in the summer, when the sap does not run as freely.

Proper pruning technique is necessary in allowing a tree or shrub to to heal a cut. Do not leave stubs! A plant cannot close over a stub, and the stub eventually dies yet remains on the living plant for an inordinate time. The stub then becomes a route for insects and fungi to the interior of the plant. Pruning to the branch collar on trees and to a bud on shrubs allows the plant to seal a cut much sooner, diminishing the opportunity for pests to infest live wood.

Boston Public Garden, Massachusetts (493480) (10791064435)
Boston Public Garden, Massachusetts; photo by Flickr user Robert Linsdell.

Shearing is a form of pruning that makes cuts willy-nilly as far as the plant is concerned, but which to people presents the plant at a uniform shape and size, the effect of which is a matter of personal taste and opinion. At no time is shearing a boon to a plant’s health, though some plants, such as boxwood and privet, are better able to tolerate it than others. The cumulative effects of this detrimental practice are evident after several years as the plant ends up with leaves growing on its outer shell only and no leaves growing inside of that, and the outer shell becomes stiff as the branches thicken. The interior clogs over time with leaves and twigs falling from the shears, allowing fungus to grow and eventually degrade the bark. The remedy for shearing is patience to make pruning cuts by hand in the proper place as far as the plant is concerned, rather than clipping it for the sake of neatness as if a living plant was inert like hair. But as always in our culture, patience is in short supply.

– Izzy