By Barb Whitmill, U. C. Master Gardener of Napa County
Spring and fall are opportune seasons to plan and create a new garden. On Saturday, February 25, U. C. Master Gardeners of Napa County will host a public workshop on drip irrigation and garden design (details below). Please plan to attend if you are plotting a new landscape or revamping an existing one.
Landscape design involves organizing outdoor spaces using both hardscape (such as walkways and walls) and plants to create a functional, attractive environment. Well-designed gardens serve their intended purpose, while minimizing the use of water, fertilizer, pesticides and labor.
Before creating your garden plan, do a site assessment. This analysis is important whether you are reworking an old garden space or starting fresh.
Evaluate the natural topography of the site: its hills, slopes and drainage. Study the sun and wind exposure in different areas. Map out existing structures such as a home, garage, pool, fences and walkways and how they are oriented to the sun.
Determine the water source for the irrigation. Locate mature trees and large shrubs that you intend to keep, and note the sun and shade patterns they create. Look beyond the property to consider views you may want to enhance or screen out.
What is your objective for the landscape and how will you use it? Perhaps you want to create an inviting entry to your home or a play space for young children. Maybe your wish list includes an ornamental or edible garden, an area for entertaining, a cooking space, a water garden, a potting shed or storage area. Consider traffic flow, how people will move from space to space. Note any concerns about loud neighbors or road noise.
Now comes the fun part, using design principles to create your landscape. Professional designers think about scale, balance, perspective and unity.
A tree planted next to a large house needs to be big when mature to fit the scale of the house.
Balance can be symmetrical—a house with identical plantings on each side of the front walk—or asymmetrical. You create asymmetrical balance if you plant a large tree on one side of the walk and several smaller shrubs on the other side.
Perspective tricks can help you visually enlarge your garden. Strong foliage colors and textures, tapering walkways, flowerbeds that draw the eye outward or “borrowing” a view beyond the property line all make a space appear larger.
Unity can come from repeating geometric shapes or design elements. For example, designing a curved lawn border for front, side and back yards will create unity.
Simplicity provides impact. Better to use a few plants in groupings rather than a lot of plants in singles. Defining the transition between plantings will create harmony.
Drip irrigation is suitable for all kinds of plantings: vegetable gardens, flower gardens, shrubs and both fruit trees and ornamental trees. Drip irrigation is efficient with little water lost to evaporation or runoff. It can be applied only when needed, and it limits weed growth as the water is supplied only to the plant. And drip lines and emitters can be easily repositioned when you move plants.
However, drip systems are not problem-free; they require monitoring and maintenance. Emitters may clog and you may not be aware that a plant is dry until it's too late. Also, drip systems can be damaged by animals, insects and humans.
Choose plants that are adapted to our climate and group them in “hydrozones” according to water needs. Each hydrozone should have its own valve that you can control individually to meet the needs of the plants in that zone. Many gardens have four hydrozones: routine irrigation, reduced irrigation, limited irrigation and no irrigation other than rain.
Most likely, your drip system will have a control center with multiple valves, a pressure regulator, a filter and a timer. Transmission to the planting area is usually constructed with PVC pipe or PE (polyethylene) hose. Emitters can be attached directly to the PE hose, or narrow tubing can be used to reach plants with emitters or sprayers. Drip tape, pierced with small holes, can be used for plants grown in tight rows, as in many vegetable gardens.
Drip emitters deliver water at a specific rate, usually one to three gallons per hour. Knowing the water needs of each plant will enable you to choose the proper emitters. Once the system is in place, each valve timer can be programmed to deliver the necessary amount of water to each hydrozone.
Anyone can learn to install a home drip-irrigation system. If you're planning a new garden or simply want to do a better job of managing your existing drip system, please attend the Master Gardener's upcoming drip-irrigation workshop.
Workshop: U.C. Master Gardeners of Napa County will host a workshop on “Drip Irrigation and Garden Design” on Saturday, February 25, from 9 a.m. to 11 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Learn how to use drip-irrigation components in your home garden in this hands-on workshop. Online registration (credit card only); Mail-in registration (check only or drop off cash payment)
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.