The most common cause of new plants failing in the landscape is improper watering. Water is the single most essential resource for new plants' growth and survival. Too much water will displace oxygen in the soil, causing the plant to slowly drown. Too little water will cause tender roots to dry out and die, ultimately causing the plant to fail.
While watering is extremely important to establish new trees, it is not complicated. Follow a few simple steps and you can ensure you are getting your new plant off to a healthy start.
How should I water?
The simplest way to water is to use an open-ended garden hose. Devices such as soaker hoses and root-feeding wands can be used but will give less-than-satisfactory results. Problems will arise if newly planted trees and shrubs are left to be irrigated by systems designed to water turf grass or flower beds.
Where should I water?
Water does not move sideways in soil, so to be effective you must water directly over the area where you need the water to go. For new plants this is directly over the root zone and the planting area. Place the open end of the garden hose at the base of the tree where the trunk meets the soil.
How much should I water?
When watering new plants it is best to water deeply and less frequently as opposed to light watering more often. This will promote a deep and healthy root system. When watering, it’s best to saturate the soil to a depth of about 12-18 inches. Let the soil dry out between watering. This will help avoid over-watering. Keep in mind that large trees with big root balls will take more time to water than smaller plants that have been grown in containers.
How often should I water?
Your soil should have a chance to dry between watering. The time you should leave between watering depends on a number of factors, including soil type, location of the plant, soil and air temperature, amount of rainfall, type of plant, and amount of mulch around the plant.
There is only one true way to determine if your plant needs water, and that is to physically check the soil. Check 5 to 7 days after you water to determine if the root zone is dry or wet. If the root zone is dry, water. If it is wet, continue to check until watering is needed. It is not safe to assume what your plant needs. Using a soil probe to delve 8-12 inches in and around the root zone will accurately tell you what your plant needs.
Watering needs to continue throughout the growing season until the end of November. This is especially important when it comes to evergreens. Evergreens will continue to lose water through the winter. If they do not have adequate water before the soil freezes the plant will show signs of stress in the spring.
What about mulch?
Like most things, mulch can be a double-edged sword. If used incorrectly your new tree or shrub will become stressed and may die. If used correctly it will reduce watering needs and keep soil temperature more moderate. New plants should be mulched three to four inches around the root zone. DO NOT MULCH AGAINST THE TRUNK OF THE TREE; this can lead to an assortment of problems later on.