How Much Is Enough?

  • Water Stress is the result of either too little or too much water, and is one of the major causes of poor plant growth and even death.
  • Most trees and shrubs should receive 1 to 1-1/2 inches of water per week.
  • Avoid using overhead sprinklers in beds. They are designed for lawns, not shrubs and trees. They put water where it is not needed and most evaporates before reaching the roots.

Follow These Two Rules When Watering:

  1. Whenever you water, water deeply (not frequently and shallowly)
  2. Put the water on the ground, not in the air or on the plant leaves.

Average Watering Times

Trees 20-30 minutes total, at a slow trickle in a triangular pattern
Shrubs 10-15 minutes total, at a slow trickle in a two-point pattern
Perennials 2-5 minutes total, at a slow trickle in a two-point pattern

Watering Frequency (after planting)

Perennials / Groundcover Roses / Small Shrubs Trees and Larger Shrubs
Week 1 Every day at least once Every other day Every third day
Week 2 Every other day Every other day Every fourth day
Week 3 Every third day Every third day Every fifth day
Week 4 Every fourth day Every fourth day Every sixth day
Week 5 Every fifth day Every fifth day Once a week remainder of growing season
Week 6 Every sixth day Every sixth day Once a week remainder of growing season
Week 7 Once a week remainder of growing season Once a week remainder of growing season Once a week remainder of growing season

Hand WateringNote: During times of extreme heat or drought move up one week.
Note: If you receive 1 1/2 inches of rainfall, this counts as a watering.
Note: If planting in a site of new construction that contains excessively compacted clay that does not drain, watering time and frequency should be reduced by half. Dig a test hole 12 inches deep and wide and fill the hole with water. If the water does not fully drain within 15 minutes, you have a drainage problem that will lead to root rot.

The smaller the plant when planted, the more quickly it will dry out. In other words, annuals and groundcovers in 12, 24 or 36 packs are going to dry out very fast, as compared with a large ball and burlapped tree. If you are hand watering a plant, visualize how big the root ball was when it was planted. A gallon pot needs less time and/or quantity of water, then a 10 gallon pot.

Some plants will show you that they need to be watered by sagging or wilting, like Hydrangeas or Ligularia (big smooth leaves). However, some plants just sag because they are in shock from being planted. Always check the soil to see how wet or dry it is - not just the surface! As a general rule - thick, hairy, waxy, silvery, and/or smaller foliage are more drought tolerant.

Water deeply, and less frequently. If you have heavy clay soil, you may need to water more slowly, so that the water has time to soak in and not just run off. Be careful not to overwater, as this will kill your plants. Water the ground, not the leaves, as this can promote disease.

In a time of drought, plants need to be watered. Homeowners may notice several years after a drought, that their tree or shrub begins to fail or gets sick. That is because the plant was weakened by the drought, thus becoming more prone to disease and pests.

Seasonal Watering

Do not depend upon rainfall to provide enough water while your plantings become established. It can take up to a year before plants have a root system that can support them. Trees and shrubs can take even longer, depending upon if they were ball and burlapped or containerized. Some species just take longer to establish and 'sulk' more.

GrassIt is important to water in the late fall - give your plantings a thorough soaking. This is especially important for evergreens, as they continue to lose moisture through their needles through out winter.

Newly seeded or sodded areas need frequent regular watering. Seed tends to be a bit more forgiving, as sod has had most of its roots cut off, when it is harvested at the sod farm. Seeded turf generally ends up being better turf, as it develops a deeper root system.

Irrigation

IrrigationIf water-wise plants are used in your design, additional irrigation won't be needed once your plants are established (after the first year, with the exception being in times of drought).

Well-established turf doesn't need to be irrigated, but will probably go dormant (turns brown and stops growing) in our hot dry summers. If you want turf to stay green, it must be watered consistently throughout the season.

We work with irrigation installers to design a system that will water your plants & turf the best way. Rotary heads are best for watering turf. Pop-up emitter heads are best for smaller areas of turf and shrub beds. Drip systems are best for perennial & annual plantings, to prevent water from hitting plant leaves.

Irrigation systems use zones. A zone is a particular waterline that covers a particular area with a set number of irrigation heads. The amount of heads depends upon the type of head to be used and the source water pressure available.