Details Landscape Art is a Marin landscape contractor, and has also served Sonoma and Napa Counties since 1991. During this time, we have seen some very poor landscaping, characterized by many common mistakes…one of which is the practice of planting trees in lawn areas without independent irrigation.
In almost all instances where trees have been planted in lawns, the owner has relied on lawn sprinklers to also irrigate the trees. Lawns are a very shallow rooted ‘plant’, and lawn sprinkler irrigation is designed to water the grass to a depth of no more than six inches. Trees, however, need deep watering to drive the roots down, and then out to create a stable base for the tree. When a tree is forced to ‘chase’ the sprinkler water, the result is a shallow rooted tree, with roots that travel along the surface of the ground, usually appearing in the lawn.
There are, however, a couple of techniques that provide a better way to irrigate trees in lawns. First is the installation of a root barrier when the tree is initially planted, which helps direct the roots about eighteen inches deep to start. Second, irrigating the tree separately with drip irrigation, or with bubblers on a separate irrigation line allows for deep watering, further driving the roots deeper. Deep root irrigators are available for purchase to further supplement deeper irrigation.
Nevertheless, we are not big fans of trees in lawns. Larger trees in lawns create shade, and lawns need sunshine to thrive. With the recent emphasis on water conservation and the resulting smaller lawns, our landscape designs usually place the trees outside the lawn area to add vertical interest to the plantings.
However, if a Marin landscape contractor absolutely must plant a tree in a lawn, we recommend:
- Only use deciduous trees which drop their leaves in winter and let in light when light levels are lowest.
- Never let the lawn grow right next to the trunk, which will stunt the tree’s growth. Always leave at least a three foot grass free ring around the base of the tree. And keep mulch a few inches away from the trunk.
- Don’t use trees that cast deep shade which is a poor environment for grass to grow
The following trees should be avoided, either because they are too large, shallow rooted or throw too much shade: -Olives
–Brazilian pepper trees
The best trees to plant in lawns are:
-Acer rubrum ‘Autumn Blaze’ – a tree that does not cast a deep lawn killing shade
–Acer rubrum ‘October Glory’ – similar to ‘Autumn Blaze’, In the North Bay should really be named ‘November Glory’
-Crabapple – many varieties, too numerous to list, almost all are disease resistant and do well in lawns
Flowering plum – easy to grow, spring flowers, deciduous, casts light shade and likes frequent irrigation
Pineapple guava – we usually grow as a shrub, but can be trained with a single or as a multi trunk tree
Variegated box elder – easy to grow, light shade, does well in lawns
Paperbark maple – beautiful bark, small to medium size, and doesn’t cast deep shade
A good Marin landscape contractor will be cautious about planting trees in lawns.