Knowing how to classify your plants by water use characteristics will help you plan your sustainable landscaping. Photo: Water Authority plant factor

Know Your Plant Factor Water Requirements

Landscaping plants have different water needs. The water requirement of each plant in your landscaping can be determined by gathering information about the plant and then comparing it to the amount of water needed by the cool-season grass growing in your climate zone.

Take a tip from landscaping professionals. They use a resource called the Water Use Classification of Landscape Species to classify plants according to their water requirements, called Plant Factors.

These water requirements divide plant species into four categories: Very Low, Low, Moderate, and High.

When you are selecting plants for your landscaping, use the classification to choose low water use plants for your landscaping. You can also use it to group a handful of higher water use plants together if you want to indulge in a few favorites.

When you have decided on your plant palette and placement, you can now figure out the water use of your entire landscape area. This will help you plan out your artificial irrigation.

Factor in watering requirements

Determine water use before choosing plants for your new sustainable landscaping. Photo: San Diego County Water Authority

Watering needs for landscape plants use a measuring stick based on cool-season turf. It’s because cool-season turf is extremely thirsty.

When you replace turf areas with climate-appropriate plants that use less water and irrigate them with more efficient systems, you can conserve a tremendous amount of water. You don’t need to turn your landscaping into a dry and dusty area to do it.

High Plant Factor: Plants needing 60 to 100 percent of the water needed for a grass lawn (PF of 0.6 – 1.)

Moderate Plant Factor: Plants needing 30 to 60 percent of the water needed for a grass lawn (PF of 0.3 – 0.6)

Low Plant Factor: Plants needing 10 to 30 percent of the water needed for a grass lawn (PF of 0.1 – 0.3)

Very Low Plant Factor: Plants needing 10 percent or less of the water needed for a grass lawn (PF of less than 0.1)

Irrigate More Efficiently By Grouping Plants

According to the San Diego County Water Authority’s Sustainable Landscaping guidebook, plant selections are colored-coded to identify their water needs under this system. It gives you an easy way to group plants by their water requirements in your new landscaping, so you can irrigate them more efficiently.

This article is part of a year-long series inspired by the 71-page Sustainable Landscapes Program guidebook. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at

Bright Ideas Bring Padre Dam MWD Landscape Contest Winner to Life

Santee homeowners removed grass, replaced the turf with a colorful, WaterSmart landscape, and won a landscape makeover contest too.

Melissa and Josh Perrell’s new landscaping at their Santee home is bursting with bright colors. Vibrant pink, orange, purple and red succulents are interspersed among lush rosemary and lavender bushes. Even more impressive, it didn’t take a single drop of irrigation over the past year to keep it thriving. The Perrells makeover project was selected by Padre Dam Municipal Water District as its 2020 Landscape Makeover Contest winner.

Most native Southern California plants do well in hotter temperatures, so summer plant care is easy with a little planning. Photo: Annie Spratt/Pixabay

Summer Plant Care

Summer is heating up! While you’re heading to the beach or pool to cool off, your landscape might need a little help keeping cool too. Summer plant care is easy with a little planning.

Native plants

Most native Southern California plants do well in hotter temperatures if they are established before the summer begins. Avoid planting new plants, repotting, or fertilizing during the hot summer months. Fertilizing in the summer can trigger more green growth, which means an increase in water needs. During hot days, it is difficult to keep up with these needs as the soil tends to dry out more quickly.

Pruning is a great summer plant care strategy to help keep growth in check and provide pest control. Save most of the pruning for the cooler months to promote growth, but light pruning in the summer can benefit plant and tree maintenance.

Water deeply and less frequently

It might seem counterintuitive to water less frequently in the summer, but this is important for summer plant care. Watering too frequently on warmer days can cause too much water loss due to evaporation. Less frequent watering will also encourage your plants and trees to grow a network of deep roots. This will benefit them in the long term.

Protect soil with mulch

A good layer of high-quality mulch helps keep soil cool and prevents evaporation. Insulating the soil with mulch can also protect thinner roots that plants use to feed from surrounding soils. Over time, these roots will grow deeper along with less frequent watering.

Mulch is great for summer plant care, but it’s also a good investment any time of the year as it helps maintain a consistent soil moisture so you can water less.

Wait until fall to plant

Timing is important when planting new plants or trees. New plants require more water more frequently to develop their new root systems. Wait until the cooler fall months to begin planting to ensure higher rates of success.

With a little planning, summer plant care is a breeze!

The Water Authority and its partners also offer other great resources for landscaping upgrades, including tips for sustainable landscaping best practices at and free WaterSmart classes at