Plant for water retention from "summary" of The Wild Garden by William Robinson

Water retention in the soil is an important part of gardening and plants play a large role in that process. They take up water through their roots and store it in their leaves and stems, which helps to ensure that a steady supply of moisture is available for other organisms in the area.

When designing a landscape, incorporating plants that are good at absorbing, storing, and conserving moisture can be beneficial. Plants with deep root systems such as trees, shrubs, and grasses can hold more water than shallow-rooted plants, making them ideal for keeping water in the area during times of drought.

Mulches such as leaves, bark chips, chopped wood, and compost can also help retain water in the soil since mulch prevents evaporation from the ground and keeps the soil moist and cooler.

To make sure your plants stay healthy during dry conditions, choose plants that thrive in low maintenance conditions such as deserts or mediterranean climates. These plants have adapted to the low amount of water they receive so will require little supplemental irrigation.

It's important to create an area around the base of any retaining wall or other man-made structures where the water can collect instead of running off. This can help to reduce runoff and erosion. Planting native plants in these areas will also ensure that you're using plants that are better adapted to the local climate.

Although most gardeners tend to focus on planting flowers and vegetables, consider adding tall grasses, rushes, reeds, and herbs to your garden as well. These plants are great at taking in excess water and transferring it to underground reserves while their leaves slow down the speed of the rainwater.