Figuring out how to water effectively and efficiently is the trickiest part of the whole gardening maintenance routine. How much water each perennial requires to stay fit and healthy depends on a number of factors:

• Climate: In climates where rainfall is regular and reliable, watering isn’t a pressing need, except during occasional prolonged dry spells or drought. (Click here for more on perennials and climate) Every climate undergoes a dry spell periodically. In arid regions, irrigation is often an all-consuming activity, becoming the garden’s artificial life-support system. Ironically, the same perennial that insists on frequent irrigation to survive in a hot, dry environment may rot in a wet climate.
• Weather: Climate is determined by average prevailing weather conditions; weather is what’s happening outside as you read this. Out-of-the-ordinary weather can wreak havoc on your plants. Windstorms and high temperatures can dry out a garden very quickly.
• Soil types: Different soil types also affect how often the garden needs water. (Click here for tips on watering particular types of soil)
• Location: In general, shaded gardens need less water than gardens in the full blast of the midday sun. However, in places where trees are responsible for casting the shadow, their roots may greedily grab water, outcompeting the flowers.
• Genetic disposition: Some plants are splendidly adaptable, enduring swamp or desert with equal aplomb. But most plants prefer some approximation of their natural habitat.

Getting Water To The Garden

The three primary methods for irrigating flower beds are the following:

• The portable system: You probably already know the old hose-and-sprinkler routine all too well. This low-cost method has multiple drawbacks, however. Sprinklers work best when every flower is the same height. Most sprinklers spray in uneven patterns, so don’t place them in the same spot each time. Sprinklers wet the foliage, which may spread diseases in the flower bed, making them a bad choice in hot, humid climates. But in hot, dry climates, wetting the foliage rinses dust off the leaves and helps prevent spider mite infestations.
• Drip irrigation: Two main types of drip irrigation are available: leaky hoses and individual emitters. Leaky hoses are either porous tubes manufactured from old tires or flat tapes with slits cut at intervals. You can lay either kind directly on top of the soil under the mulch (as shown in the image below), or bury them a few inches deep. In another type of drip irrigation system, you wind rigid plastic tubing through the flower bed. You place the individual emitters that are attached to the line directly on the root ball of each perennial. This system is highly efficient at delivering water.
  

  Click here to learn more about drip irrigation

  
  Snake leaky hoses back and forth between the plants in the flower bed.

• The automated system: Both sprinklers and drip irrigation can be fully automated.  ....read more