Conserve Water In Your Landscape

Key points

• In our changing climate, more severe droughts are expected in Maryland, in addition to stronger storms and flooding. Weather extremes put stress on our natural water supplies, water quality, and the infrastructure that delivers water to our homes and other facilities.
   
• Droughts can lead to temporary or permanent plant damage. Symptoms and consequences of drought in plants may include wilting, leaf scorch, reduced vegetable and fruit harvests, premature fall color, and early defoliation. Drought-stressed plants are more susceptible to pests and diseases.

• If severe drought occurs in Maryland, cities, counties, and the Department of the Environment may put restrictions on some water uses, like irrigating lawns and washing driveways, in an effort to conserve the drinking water supply. The U.S. Drought Monitor website provides information on drought severity each week.
   
• Gardeners can adapt their landscapes to prepare for and cope with droughts, using a variety of water conservation practices. These steps can save you money on utility bills, save time on watering tasks, protect the health of your plants, and make the most of a limited natural resource.

Water use in plants and coping with drought 

Plants are like water pumps. They absorb water and nutrients from the soil to use for growth and release water vapor through pores in leaves (stomata), a process called transpiration. Water movement in a plant is influenced by the atmosphere around the plant, temperature, and soil conditions. For example, dry air and breezes around a plant increase the transpiration rate, pulling moisture through more quickly. Warmer temperatures increase evaporation and cause the soil to dry out more quickly too. In general, plants begin to wilt and suffer drought stress when the transpiration rate exceeds the water available in the soil.

Plants have various adaptations to regulate their water use and storage. Some species have evolved to have small leaves, thorns, or waxy or reflective surfaces to minimize water loss in arid habitats. Some plants have large fleshy (succulent) leaves to store water longer. Root systems have adaptations to reach for groundwater.

When water is limited, plants respond to conserve moisture. Responses vary by species and include closing the stomata (leaf “breathing” pores) during the heat of the day, shedding some leaves to reduce water loss, and changing the chemical composition in their cells to minimize damage from harmful molecules (free radicals) that concentrate when water in the plant is limited. Scientists are investigating how increasing levels of carbon dioxide in the atmosphere and the related heating effects of climate change create opposing forces that influence the water balance in plants.

Drought symptoms and consequences in plants

For gardeners, the first symptom of water stress in plants is usually wilting. Additional symptoms include:

Upward curling or rolling of leaves

• Yellowing and browning of leaves, particularly along leaf margins and tips 
• Under-sized and off-flavored fruits, vegetables and nuts 
• Under-sized leaves; limited shoot growth
• Flower and immature fruit drop 
• Interior needle and leaf drop on conifers and evergreens 
• Chlorosis symptoms on foliage (yellowing between the leaf veins)

Secondary and more severe impacts of drought stress may include:
Increased damage by insects (e.g. borers) or other arthropods (e.g. spider mites)

• Increased susceptibility to certain plant diseases (e.g. Botryosphaeria)
• Blossom-end rot of tomatoes, peppers, squash, and melons
• Diminished winter hardiness
• Root death
• Dieback of branch tips and young growth, progressing to twig and branch death (this can also occur in the spring following a severe summer drought)
• Eventual plant death

Read more about the symptoms of drought and excessive heat stress.

Water conservation practices

In our warming world, gardeners may need to water more carefully to keep plants healthy and thriving, while also being mindful that water resources are limited. Making gardens and landscapes more resilient to dry conditions can be approached in two broad ways:

1. Reduce the need for watering in the first place. This can be done with good soil management practices to hold rainwater in the soil longer, thoughtful selection of drought-tolerant plants, management of runoff, and capturing and holding rainwater on-site for later use.
    
2. When irrigation is needed, use practices to minimize water waste. This includes monitoring soil moisture level, mulching, timing and targeting your watering to top-priority plants, and using water-conserving irrigation equipment only as needed.

Create a water-wise landscape

• Xeriscaping is a style of landscaping that minimizes or eliminates the need for irrigation. Traditionally this involves the use of Xerophytic plants, like cacti and succulents or other plants that have natural adaptations to dry conditions (e.g., small leaves, succulent leaves, white or silvery reflective foliage). However, this does not mean you are limited to using cacti and succulents. Xeriscaping is a concept or an approach to landscaping that is intended to reduce water use. It involves thoughtful selection and placement of drought-tolerant plants, covering the ground to minimize water loss, and using minimal irrigation efficiently, if at all.

• Many Maryland native plants fit well into a drought-tolerant garden. Examples of drought-tolerant native plants include: Northern Bayberry (Myrica pensylvanica), Adam’s Needle Yucca (Yucca filamentosa), Butterfly Weed (Asclepias tuberosa), and Coreopsis (Coreopsis lanceolata). Native grasses such Switchgrass (Panicum) and Indiangrass (Sorghastrum nutans) have deep root systems and can handle dry conditions. Additional choices for drought-tolerant native plants are listed in this publication: (PDF) Conserve Water: Protect the Chesapeake Bay
   
• Chesapeake Bay-wise landscaping, conservation landscaping, and water-smart landscaping are related approaches that emphasize water conservation and other sustainable practices with a multitude of benefits. Consider getting your yard Bay-wise Certified by the University of Maryland Extension and feel good about the steps you are taking to make it more sustainable.

Improve your soil for better water holding capacity and infiltration

• Add organic matter to your garden regularly to increase your soil’s water-holding capacity. This refers to the amount of water your soil can hold and provide to plant roots. Soils with greater organic matter and less compaction allow rainwater and irrigation water to soak in more gradually rather than running off to drainage systems. Learn about organic matter you can use to improve your soil, such as compost, manure, and cover crops.
   
• For an established lawn, organic matter can be added in the form of grass clippings, chopped leaves, or compost. Refer to our guidelines on organic lawn care.

Use mulch to retain soil moisture

• Cover bare soil with mulch. Mulches help to moderate soil temperature and slow evaporation from the soil so it will stay moist longer. The rough texture of mulch traps water and allows it to percolate slowly into the soil rather than running off the surface.
   
• Organic mulches like arborist wood chips, leaves, shredded bark, pine needles, straw, and grass clippings are especially beneficial because they return nutrients to the soil as they decompose. This improves soil structure and water-holding ability. 

Group plants with similar watering needs

• Create zones that group plants together with similar water needs. A native plant garden may not need watering at all (once established) and you can focus instead on setting up a water-wise irrigation system where it is most needed, such as for a vegetable or container garden.

Control weeds

• Weeds compete with desired garden plants for water. Control weeds promptly by pulling or digging them out. Refer to our page about managing weeds.

Lawns and lawn alternatives

• Reduce the overall size of your lawn. Lawn is difficult to maintain in Maryland’s climate and maintaining lush, green growth often requires more watering than other landscape plants.
   
• In areas where turfgrass will not grow well or is difficult to maintain (under shade trees, on slopes, in soggy soil), grow other types of perennial plants that are more suitable. For ideas, refer to lawn alternatives and converting lawns into diverse landscapes.
   
• For most situations where lawn is desired, turf-type tall fescue is a drought-tolerant choice. Tall fescue and Kentucky bluegrass go dormant in summer droughts. They will usually recover when drought ends and cooler weather returns. However, in severe drought, even dormant grasses can die. 
   
• Mow the lawn high. Cool-season grasses like tall fescue and fine fescue should be mowed at a height of 3-4 inches in the summer. This reduces moisture evaporation from the soil and also reduces weeds.

• Aerate lawn soil in the fall to reduce compaction and improve water infiltration.
   
• If you water your lawn, do so on an as-needed basis (e.g., during seed/sod establishment) not on a regular schedule. Water slowly to prevent runoff and water in the morning to reduce leaf wetness that can lead to disease problems. Read our lawn watering tips for best practices.

In the vegetable garden

• Improve your soil with organic matter by using compost and cover crops.
   
• Set up a drip irrigation system and use mulches like straw, biodegradable paper (comes in a roll), or reusable weed barrier material to cover the soil, reduce weed competition, and conserve moisture.
   
• Shade cloth (30% shade cloth, a mesh material that blocks 30% of sunlight) used over summer crops like tomatoes and peppers can help to reduce water loss (transpiration) from plants and has been demonstrated to improve crop quality and yield.
   
• Put container-grown vegetables in a location where they will get some protection from afternoon sun/heat and wind, to reduce drying out.

Capture rainwater for later use

• Connecting a downspout to one or more rain barrels or a cistern is a way to collect and store rainwater for later use in your garden. Learn about installing rain barrels and cisterns.
   
• For vegetable gardeners, refer to Rain barrels: testing and applying harvested water to irrigate a vegetable garden from Rutgers University.
   
• Downspouts can be directed to let rainwater flow into a garden or portion of your yard where the water can soak in naturally and recharge groundwater. Learn about disconnecting and redirecting your downspouts.

Build with permeable pavers and porous hardscapes

• If you have an opportunity to build or replace a patio, walkway, or driveway, consider the benefits of using permeable materials that allow water to soak through and go down into the ground rather than running off to storm drains.
   
• Learn about creating permeable hardscapes.
   
• Some Maryland counties offer rebates or tax credits to reduce the cost of installing permeable hardscapes. Check with your county government office.

Water only when necessary and prioritize your watering

• One to two inches of water may be needed each week, depending on the types of plants you are growing, stage of growth, soil type, and weather conditions. Keep track of rainfall amounts using a rain gauge and monitor local drought conditions. Read our watering guidelines for trees and shrubs, vegetable gardens, and lawns. Periodic deep watering is better than shallow, frequent watering, to encourage deep root growth, although this depends on the plant.
   
• Water in the morning when possible. Watering in the hottest part of the day results in loss due to evaporation. Overhead watering late in the day can increase chances of disease due to leaf wetness for an extended time.
   
• Prioritize your watering. Focus on plants that are of highest value in terms of their function in the landscape and replacement cost. Below is a rating system to prioritize your watering in times of drought.

Use irrigation wisely: Drip tape & soaker hoses

• Instead of sprinklers, invest in soaker hoses or a drip irrigation system to use in your garden. These operate at low pressure and deliver water slowly and efficiently to the root zone of plants and minimize water wasted to runoff and evaporation. Learn how to set up a drip irrigation system.
   
• Look for irrigation system components that are WaterSense® certified by the U.S. Environmental Protection Agency.
   
• Turn off the irrigation system if rainfall is sufficient. Water when needed, not on an automatic timer.
   
• Repair leaky garden hose connections. 

Capture and reuse graywater

• Graywater is household water that has been used (for showering, washing dishes). This water can be used to irrigate non-edible garden plants and landscaping. Graywater from a shower or sink should be used within 24 hours. Avoid using water that has been through a water-softening device. The Virginia Cooperative Extension has a fact sheet: (PDF) graywater reuse.
   
• The Maryland Department of the Environment is in the process of developing guidelines for the installation, operation, and maintenance of graywater systems in facilities.