Grass Removal Mandates and Landscape Water Use

Q. Because we are an HOA, we are mandated to remove the grass surrounding our condos.  We have over 100 mature trees. What is the best irrigation to put on these trees after the grass is removed?  We want to save as many trees as possible. My particular unit had the grass removed many years ago and I have a large pine tree.  It is irrigated with drip emitters surrounding the tree about 4 feet from the trunk.  It is doing fine.

There are lots of reasons why large pine trees do well when the lawn is removed and drip irrigation is installed. Notice shrubs irrigated nearby. They need water as well and may be feeding the tree water.

A. Yes, lawns are big water users. Some types of grass (tall fescue in particular) needs daily watering during the summer and use about 7 feet of water (7 x 12 = 84 inches of water) each year to look good and lush. Bermudagrass lawns use less; about 4 and a half feet of water (54 inches) each year. Less, but still not low enough. We want to get our total landscape water use averaging around two feet of water each year. It makes sense that lawns are targeted because of their higher water use.

Newly planted Chinese pistache in a lawn. The roots of this tree will grow more shallow to accommodate the frequent lawn watering and other shallow rooted plants growing at its base.

t is not only HOAs. Any entity that has property is required to conserve water by removing lawns.  I would also include trees too large for the area and “out of scale” with the home. Just substituting lower water use plants, and finding a lower water use irrigation system alone, does not work. You will lose some trees, particularly the large ones.

Pine trees with adequate water will be full and the limbs will be growing strong.

Do you want to choose where water is applied or have someone decide for you? Lowering total landscape water use requires finding a balance between open areas that need no irrigation with areas that require irrigation. Total landscape water use is finding a suitable balance between the two. A less complicated reduction in total water use is finding a balance where water it is needed and where it is not.

Growth of pine trees comes from the ends, terminal buds. The new growth should be, in older pine trees, average about 10 to 12 inches.

Your landscape committee should be charged with identifying zero water use areas. Filling these areas may include the use of statuary, murals, paintings, gazebos, etc. They don’t need water. Start by identifying areas where loss of plants is not as important as other places. As these places eliminate the need for water, substitute statuaries, murals, paintings or gazebos that need no water but still beautify.

Landscape art (no water) should draw your attention. It can substitute for a lack of plants that need water. Landscape art can be an investment. 

Next, shade the south and west sides of buildings to prevent overheating of these units during the summer. Use deciduous trees for solar heating during the winter. Consider removing large plants on the north and east sides of buildings that have little function in heating or cooling the home. If plants remain or you find other plants, concentrate on smaller plants (less than 20 feet tall for single story homes) that use less water. Water the remaining trees and shrubs in irrigation “clusters” for ease of water delivery and finding leaks.

Even though it may be considered a desert tree, if it's not needed or the size is too large for the spot, get rid of it of make is smaller to save water.

            Water savings come from the “averaging” of water use over the property and the creation of non-irrigated “open” spaces. You can have your cake and eat it to but not everywhere! These open spaces instead may use statuaries, murals, paintings and gazebos that don’t use water.

This west side of a hospital in Parker, Arizona, shaded the windows and walls with low water use trees that don't get all that big. The rest of the landscape uses minimal water.