We all know that plants, especially those newly planted, need water. But how much water is really necessary? Luckily, there is an easy solution using just a milk jug (see tip, below). To begin, water at initial installation of plants then again once or more weekly depending on plant size and whether they were grown in a nursery pot or burlap. 
Water plants that were grown in nursery containers every 3 days for the first 3 weeks after planting. We suggest using a watering wand. After 3 weeks, water only when necessary depending on weekly rainfall amounts. Times of drought will require more frequent waterings.
For a 1 gallon planted pot, ½ gallon of water per watering is sufficient, for a 3 gallon pot, you will need 1½ gallons of water, a 5 gallon pot would require 2½ gallons of water per watering and so on….
While sprinklers and soaker hoses are helpful, they usually do not provide sufficient water during the establishment period. Hand watering with a watering wand works best.
Water plants grown in burlap once or twice weekly. Keep this schedule for 3 weeks. After 3 weeks, water only when necessary depending on weekly rainfall amounts. Times of drought will require more frequent waterings. We suggest using a watering wand. Exception: some burlapped Rhododendrons, Azaleas and Pieris will require more frequent waterings of 2-3 per week and a duration of 6 weeks.
Use 10 gallons of water for each inch of tree trunk diameter or use 1 gallon of water for each foot of plant height or width. Evergreens over 3 feet will need 2 gallons of water for every foot of height. Conifers and evergreens such as Arborvitae have a heavy canopy and should not rely on rainfall for the first year.
You do not need to measure water when watering a newly planted plant except for just once. Take an old milk jug and fill it using your watering wand or spicket. Using your smart phone’s timer app or other type of timer, figure the amount of time it takes to fill that one gallon jug. If it takes 30 seconds then you know you must allow water to flow on the plant’s roots for that amount of time multiplied by the data given in the above article. For example, a 3 gallon pot would need to be watered at soil level for at least 90 seconds each time. Also, when watering several plants, water less at one time and repeat as necessary to reduce water runoff.
For hardy trees, shrubs, perennials and roses, we recommend Holly-tone and Plant-tone as fertilizers. Holly-tone is used for acid loving plants such as Dogwoods, Evergreens, Hollies, Rhododendrons, Azaleas and their relatives. Plant-tone is used for most other plant species.
We recommend the following easy to remember dates for annual fertilizer applications:
April 1st – April Fools Day May 31st – Memorial Day July 4th – Independence Day
October 31st – Halloween