Perhaps the knottiest problem the lawn-builder has to face is trying to make grass thrive where it just naturally does not want to thrive - in shade. The shaded lawn, if we are to judge by the high percentage of failure, has not yet benefited greatly from modern scientific advances in other phases of turf culture.



Under the branches of trees (which is what most people mean by shade), three of the four vital elements of growth are wrong for grass. All plants need heat, light, moisture and food. We can dismiss heat as a problem: usually temperatures under trees are adequate for growth. What about the other three?

In The Right Light

Light is the one lack which is all but impossible to make up. Unless we are willing to trim trees high, or even cut them down, not much can be done about light.

As to food and water, deep-rooted trees, such as planes and oaks, are not as greedy as those with shallower root systems such as the white ash and the maple. Nonetheless, any tree removes vast amounts of water from the soil - easily a barrel or two a day for a mature specimen. Since this moisture is removed from below, it is not available to rise to the surface by normal soil capillary action.

We can readily see, therefore, that moisture will always be scarce under trees. Even when liberal amounts of fertilizer are used, this does not always make up for a lack of plant food in areas under deep-rooted trees because lack of moisture keeps it from being available.

With food, light and moisture all critical factors, the growing of grass under trees is a really knotty problem to solve. Unless water can be supplied (at least enough to keep the grass going through the driest periods), a turf cannot be maintained. Disjointed plants are possible, but they do not run together and form a real sod.

The new ureaform fertilizers are excellent if moisture can be supplied, but if the soil is dry, bacteria cannot break them down, and they fail to feed. For this reason, perhaps the best way to feed a shaded lawn is with liquid fertilizers watered through a hose with a siphon device which sucks up a concentrated solution and adds this to the water in the line.

Best Shade Species

The best grasses for shade are Pennlawn Fescue, with Penn State or Illahee Fescues as second choice, and perhaps with a little Merion on the chance that the shade is not so dense that this will fail. Poa trivialis should be included in a shade mixture only if the spot to be seeded is low, moist and rich.

I know this is contrary to all recommendations in the literature on lawns, but anyone who has grown Poa trivialis experimentally under controlled conditions knows that it has high moisture and food requirements, which cannot be met under ordinary shade conditions.

If only Velvet Bent were not so costly! This is a grass well adapted to shade, and while it can use more food and water than the fescues, it can also survive without these extras and will do very well. Its color and texture are superior to the fescues.

Where the amount of sunshine will total three hours a day, I strongly urge a trial of Merion Kentucky Bluegrass. This grass will tolerate more shade than is commonly realized. Its one drawback as a shade grass is that, to thrive, it must be well fed. It can get along with less moisture than most grasses.

The soil under trees can be improved, but beware of peat moss under such conditions unless artificial watering is used. Peat moss is very hygroscopic, and will draw moisture to itself at the expense of the surrounding soil. Peat moss can absorb so much water that the rest of the soil mass mixed with it will dry out.

All is not lost if you have trees in your lawn. Grow any of these grasses in the shaded areas and you will have success.