Choosing individual plants can be the most fun and rewarding part of designing your new landscape. The key to success is selecting the right plant for the right place in your landscape. Using trees, shrubs and other plants that are adapted to your regional climate and site conditions will help ensure success and save water.
Plants in your design
What are the basic plant materials you have to work with?
Trees usually have the biggest design impact, and may be in your garden for generations. Trees may need supplemental water. Group trees together to shade each other and raise humidity levels, thereby reducing water demand.
Trees will also create a “microclimate” for under-story plants that prefer cooler temperatures and shade (azaleas, camellias and rhododendrons, for example).
- Evergreen trees provide strong textural statements and are often used for screens and backgrounds. Plant in northern exposures or away from structures.
- Deciduous trees lose their leaves in winter. Plant deciduous trees on east, south, and west-facing walls to provide summer shade and winter sun.
- Do not plant trees in an irrigated lawn. Lawns require more water than trees, and over-watering trees can adversely affect their health and lifespan.
Shrubs range in height from 1-foot to 15-feet or more with multiple stems. There is a wide variety of shrubs adapted to all kinds of climatic conditions (dry to moist, hot to cold) and therefore offer many choices for your garden. Shrubs are ideal for making hedges to screen views, create privacy and can be used as “living fences.”
Many shrubs are fast growing and require little water once established. It is important to provide adequate space for the particular shrub variety selected so it can grow to its natural size and shape and not require excessive pruning or shearing.
They provide an inexpensive screen with color and interest. They are usually grown on fences, or on arbors and trellises to provide shade.
Low-Growing shrubs, vines, and perennials
Arrange these plant types in groups of like species to create a mass effect. Place plants according to their mature width. If mixing varieties, they should have similar water needs.
Grasses provide a versatile choice for your garden and range in size from a few inches tall to over 20-feet (bamboo). They are tolerant of many conditions and will provide interesting structure, flowers, and winter form to your garden.
Ground covers will tie the plant layout together and can often be used in place of lawn.
Lawn provides aesthetic benefits and is good for active play areas, but it is also one of the highest water users in your garden. Limit your use of lawn – consider how much lawn you actually need and place it only where it will be used. Choose grass varieties most adapted to your climate.
Warm season varieties use considerably less water than cool season varieties (see Selection of grasses and Lawn care for more information).
Annuals, perennials, herbs and vegetables
Annuals such as pansies and impatients last only one year as their name implies and must be replanted. They are also often high water users. Annuals are usually used in smaller garden beds as a focal point of seasonal color.
Perennials such as day lilies, iris and salvias come back year after year and are available in an al most infinite variety of flower colors and foliages. They can be very water efficient and are the best bet for a colorful low maintenance garden. Some herbs such as rosemary, lavender, and thyme are perennials and make excellent garden plants. If you want to grow vegetables, reserve area with full sun, rich cultivated soil and access to water.
Right plant for the right place
The key to a successful landscape project is choosing the right plant for the right place on your property. Selecting plants that are adapted to your local conditions should grow better, require less maintenance and use fewer inputs such as less water, fertilizers, and pesticides. When selecting plants consider the following factors:
- Climate – always select trees, shrubs and other plants that can withstand the temperature and other climatic extremes in your region.
- Microclimate – consider the microclimates of your yard, such as sun or wind exposure and choose the appropriate plants for the appropriate place in your plan.
- Water needs – group plants in your landscape design according to their water needs or the “hydrozones” so they can be watered efficiently. Avoid high water-using plants.
- Soil and drainage – consider the soil preference of the plants you select. Some plans thrive in well drained sandy soils, while others prefer moist clayey soils. Most prefer something in between known as loam.
- Placement in the Landscape – know the plant’s growth potential and provide enough space it to reach its ultimate width and height. This will allow the plants to achieve their natural shape (and save you years of pruning!).
Determine your regional climate. This will ensure that you select plants that are “cold hardy” and can survive in the temperature extremes of your region. Use the U.S. Department of Agriculture Plant Hardiness Zone Map to determine your regional climate zone.
Your property has its own microclimate conditions determined by the orientation of your house and existing vegetation that either protect or expose plants to the elements. Carefully note the sun, shade and wind patterns on your property over the seasons. Choose plants fitted for these conditions.
Trees, shrubs, vines, and ground covers can also be used to change the microclimate of your yard, providing shade as well as reducing energy demand for heating and cooling. Plants also create microclimates that retain the moisture that would normally be lost through evaporation.
Water needs and hydrozones
Each plant variety has its own water needs. Ideally, you should select plants that are adapted to local rainfall. Locally adapted plants will only need watering in order to get established or in times of severe drought. But it is not necessary to exclude all plants that will require regular irrigation from your design.
A key concept to saving water and promoting plant health is to group plants according to their water needs in “hydrozones.” Perhaps your design has a small area of lawn, a larger area of flowering perennials, and another area of native shrubs and trees.
You will have a minimum of three hydrozones: Zone 1 for high water-using plants (turf), Zone 2 for medium water-using plants, and Zone 3 for low water-using plants.
Grouping plants into hydrozones will result in compatible plant groupings, and will enable you to water much more efficiently and improve plant health. Modern irrigation controllers typically allow for at least 12 irrigation zones, and each zone can be scheduled to automatically apply the right amount of water to each plant grouping. See STEP 3 Install Efficient Irrigation for additional information.
While some plants prefer sandy well drained soils, and others prefer moist, clayey soils, most prefer something in between called “loamy soil.” For a quick and easy way to determine your soil type, drench a patch of soil, and let it dry out for a day.
Pick up a handful of the moist soil and squeeze it firmly. If it forms a tight ball and is slippery, it probably has high clay content. If it feels gritty and crumbles when you open your hand, it is sandy. If it is slightly crumbly but still holds a loose ball, it is a loam combination.
Soils that are too sandy or too clayey can be improved by mixing in ample amounts of organic matter, such as compost or peat. A 3-4 inch layer roto-tilled into the planting bed will help.
Before investing in any landscape project, however, it’s a good idea to have your soil tested. Your local university cooperative extension will test your soil for a small fee and provide you with information regarding texture, water-holding qualities, acidity, nutrients, and salinity.
In addition, they will provide specific direction on fertilizer needs and soil amendment opportunities. It may be more practical and less frustrating to select plants that are appropriate for your soil conditions than to change your property for the plants.
Native plant species from your state or region are al most always more suited to your soils than non-native, exotic plants. See Soils and Drainage for additional information.
Below is a summary of tips for the appropriate placement (or selection) of plants for your new landscape. These will result in water savings, reduced maintenance, and reduced costs.
- Group plants in your landscape according to their water needs (as discussed above) – this will result in compatible plant groupings, and will enable you to water much more efficiently.
- Place plants preferring moist soils in areas that stay cool longer throughout the day – These include areas with afternoon shade, the north side of fences or structures, high water tables, and areas adjacent to water runoff.
- Place plants that prefer drier soils in areas that are more exposed to sun and wind – These include areas away from structures and shaded areas.
- Space according to the plant’s growth potential – Provide enough space for a plant to reach its ultimate width and height. This will save you years of added maintenance costs and labor.
- Do not plant trees in your lawn – Lawns require more water to stay healthy, which can adversely affect the health and lifespan of the tree.
- Avoid narrow or oddly shaped lawns – Narrow strips of turf or irregularly shaped lawns are difficult to irrigate efficiently and generally result in overspray and runoff.
Here are some additional tips on the selection and placement of trees and shrubs in your design that can beneficially change your yard’s microclimate and provide significant energy savings:
- Plant trees to shade south- and west-facing windows, walls, and outdoor living spaces. A mature tree can reduce air-conditioning costs by more than 30 percent. Deciduous trees provide shade in summer, and in winter they allow the sun’s warmth to pass through and warm your home and garden. Deciduous vines and shrubs can also be used with benefits similar to that of trees.
- Shade patios and seating areas during the hottest part of the day with trees or arbors planted with vines.
- Shade paved areas and air conditioners. Shading paved areas on your property will reduce the heat build-up. Shaded air conditioners don’t work as hard to cool the air, providing further energy savings.
- Protect garden areas from drying winds. A row of trees or tall shrubs can buffer your property from strong winds that can cause unprotected soils and plants to dry out.
Ideally, you should select a plant palette of species native to your region. Over time, native plants adapt to the limits of their natural environment. They are perfectly suited to your climate and soil. Numerous resources are available on regional natives around the country.
Contact your university cooperative extension, botanical garden, a good local nursery, or local bookstore. Many water utilities also have excellent plant resource guides available to you.
STEP 3 provides advice on designing and installing efficient irrigation systems for your new landscape.
- Hiring a Landscape Professional - January 19, 2017
- Water-Wise Plant Materials - January 13, 2017
- Water-Wise Plants Timing and Seasonality - January 13, 2017