Drought, whether it is seasonal or long term, causes numerous problems in a garden but it is particularly tough for newly planted trees and shrubs. Annuals and containers are also difficult to keep hydrated during an extended dry summer. Unfortunately there are many times when we do not know that a summer is going to be excessively hot and dry until it hits, but there are some things that you can do in the garden to help make a difference to your plants and to your watering schedule if the rainfall is scarce.
There are several approaches that you can take to ensure the garden survives a drought and they include good plant choice, irrigation techniques, and setting priorities.
As a general rule, annuals and containers are the thirsty elements in your landscape and are kept to a minimum as well as close by the water supply. Newly planted annuals need to be watered at least once every day until they are well established and most days in the summer season. A timer and overhead sprinkler set to irrigate a mass planting of annuals works well to hydrate then each morning. Containers and hanging baskets that are on a sunny porch will probably need to be watered morning and evening. An extension to your hose will help you reach high baskets, and consider investing in a self-watering container or using a water barrel to collect water when it rains. Water barrels fill quickly with just a modest rainfall and the tap at the base can deliver water to your water can for containers. Self-watering containers have a reservoir in the lower half that you fill with water and the plant roots access that moisture. Refill the container every day or two and save time when you water.
Established perennials do not need as much moisture as annuals, but even mature perennial beds need watering every few weeks in a drought, and newly planted perennials need to be watched carefully for the first year. Larger leaved established perennials are the first to show signs of wilting in the morning when they need water. Although the perennial bed can be watered with an overhead sprinkler, it is more efficient to use a soaker hose. In spring, when the plants are breaking dormancy, wind the hoses close to the plants. When you attach a garden hose to the end of the soaker hose, the water seeps out and hydrates the root zone of the plants where it is needed. Adding some drought tolerant perennials such as Gaillardia also helps to keep the perennial bed looking good all summer.
Trees and shrubs also need to be watched during a long term drought. The overall water table and moisture in the subsurface is depleted and unless the tree and shrubs are well established their roots struggle just as those of perennials. Shrubs that are in the same border as the perennial can be watered along with the perennials, but for trees and shrubs that are sat in the middle of the turf you will need to attend to them individually. A good way to water mature trees is to place a hose nozzle close to the trunk of the tree. Turn the water on so that it trickles out of the nozzle. Leave the hose running for a few hours to allow the water to move into the root zone of the tree. Newly planted trees need to be watered every few weeks, mature established trees need attention only if the drought is extensive and they start to show signs of stress.