Most shrubs require about 3 gallons of water at least twice a week. These plants are vulnerable to water loss during the first growing season, so it is important to learn how to water new shrubs so they will flourish and live a long and healthy life.
Water by Hand
Attach a pistol-grip nozzle to the end of a garden hose.
Check your watch or start your stopwatch or timer and begin to fill a 5-gallon bucket.
Fill the bucket approximately 1/2 to 2/3 full. This will represent an amount between 2 1/2 and 3 gallons. Make note of the time it takes to fill the bucket.
Water your newly planted shrub from your garden hose for about the same amount of time it took to partially fill your 5-gallon bucket.
Use Drip Irrigation
Make a drip irrigation system out of a 5-gallon pail.
Drill several 1/8 inch holes along the sides of the bottom of the bucket. Holes drilled into the bottom of the bucket will clog quickly, so place your holes on the side of the bucket, about 1 inch from the bottom.
Place the bucket next to the shrub, within the perimeter of the recently-dug hole. If the ground is sloped, put the bucket on the uphill side. Every 2 to 3 days, fill the bucket 1/2 to 3/4 full. If the bucket is not emptying fully during this time, drill several more holes in the base.
Mulch To Conserve Water
Apply a 2 to 4 inch layer of mulch to conserve water, reduce weeds and keep the soil cool. Do not use more than 4 inches of mulch; too much can reduce the amount of oxygen available to your plant.
Use shredded leaves, pine straw, peat moss or wood chips. It is not necessary to remove mulch when watering; water will permeate the porous material and soak slowly to the roots.
Keep mulch at least 1 to 2 inches away from the trunk of the shrub. This prevents bark decay and discourages damage from foraging rodents.