The cool shade of a large oak tree can make outdoor living in summer bearable. Lucky are those who are gifted with large oak trees in their yard. They can add value to the property in real estate terms, as well in the casual living we enjoy in the foothills. Quite often one of the first impressions we have of the foothills is the park like atmosphere of rolling green hills dotted with the majestic beauty of the Blue Oak (Quercus douglasii), or California White Oak (Quercus lobata).
Most people love their oaks so much they want to create beautiful gardens underneath, so as to enhance their beauty. This is why plants like azaleas, camellias, rhododendrons, etc., are often planted underneath the cool shaded canopy of the native oak. While the idea is attractive enough, the reality is all together different. These well meaning gardeners may be actually destroying the tree, which provided the shade for the planting in the first place.
Native Oak trees have grown up with virtually no water in the summer and early fall. Our Mediterranean climate is wet in winter, and dry in summer. This is quite unlike the rest of the United States where summer rains are frequent. When we begin to water the shrubs the oak will be watered too and we may end up causing fungal root diseases that could eventually kill the tree. To prevent this possibility it is important that any planting that goes on under the canopy of the tree be located away from the trunk and be the type of plants that require little or no summer watering. It is especially critical that no sprinkler be located so that water splashes on the trunk of the tree. Drip systems are the best choice for watering under oaks. This will avoid getting water anywhere but where the planted shrub will be. Lawns are really a no-no under oaks, as a sprinkler system must be used frequently to keep the lawn healthy.
When choosing plants for under oaks you must first determine if it is shaded, or will receive lots of afternoon sun. We will also choose drought resistant plants, and water only enough to keep the plant healthy. In sunny to lightly shaded situations some plants to consider are, Manzanita (Arctostaphylos), Toyon (Heteromeles), Strawberry Tree (Arbutus unedo). In shaded to lightly shaded areas try Winter Daphne (Daphne odora), Sweet Box (Sarcococca) or Nandina (Nandina domestica). Trailing Manzanita (Arctostaphylos uva-ursi), Arron’s Beard (Hypericum calycinum), and some Rockrose (Cistus) make good groundcovers in sunny or lightly shaded areas. Wildflowers planted under oaks are also an interesting solution. The wildflowers will sprout in the late winter, and bloom through the spring. With no irrigation they will turn brown and die at the beginning of summer. This is the time to mow the brown stems and flowers down. The seed of the wildflowers will have spread throughout the area laying dormant until the rain return next winter. No extra water necessary for this solution. Plant the wildflowers in the fall just before the rains begin.
Your yard is greatly enhanced by the presence of beautiful oak trees. Your home’s value is increased by the presence of these majestic beauties. To protect them be sure to check with your favorite horticultural professional on the best solutions to enhance the beauty of your yard, while protecting the oak trees, which provide so much of the flavor of our casual foothill living.