Watering Guidelines

Trees & Shrubs

Plant survival is directly related to the care plants receive after they leave the Nursery.  One of the most basic concepts is adequate moisture.  Without it, plants cannot survive.  Water Requirements for newly installed plants are fairly simple: the roots should never become completely dry or waterlogged.  If necessary the soil should be amended to solve drainage or moisture retention problems.  The crucial part of supplying “adequate moisture” is to complement natural rainfall on an ongoing basis through the following steps. 

Soil Sampling:  Dig down with your finger 2-4” just outside the root mass of the plant you are watering and check for moisture.  Water only if the soil is dry to the touch.  Feeling the soil is the best method for gauging the dryness of the soil.  Only Sampling can tell you when the soil is adequately moist, too dry, or too wet.   
Corralling  the water: “Well” all newly installed plants by creating a circular berm of soil around the outer edge of the planting area. This (3” to 4” high saucer) helps the measurement and placement of water on the root zone, especially for larger shrubs and trees. 

Keeping track of water volume:  Apply measured amounts of water depending on the size of the root ball.  The following chart is a guideline for the amounts of water needed by newly Planted trees and shrubs.  Plant Species have varying water requirements,  so make sure to check the soil first to check moisture content.  We will discuss perennials later on.

Plant Size

Amount of water per application

Small shrubs(<3 feet)

4-5 gallons

Large shrubs(>3 feet)

7-10 gallons

Small Trees(<2” caliper)

7-10 gallons

Large trees(>2” caliper

10-20 gallons

Water measurements are made by using a watering can, bucket, water meter, or by calculating the gallons per minute flowing through the hose at a known setting.   When watering with a hose, turn on the water at a low setting and count the amount of time it takes the water to fill a one gallon container.  Multiply that amount of time by the number of gallons you need for your plant.  That total provides the amount of time you will need to run the hose (at noted setting) in order to adequately water your plants.  For Example, if it takes 5 min to fill a gallon jug at a slow trickle and you need to water a large tree (see the water guideline chart) then you need to let the water trickle over the root mass for 50 to 75 minutes each time you water ( 5 minutes X 1o to 15 gal) needed per application = 50 to 75 minutes. 

Evaluate Frequency: Newly installed trees, shrubs and perennials should be watered in deeply when planted and then be checked every few days using the finger test to see if water is needed for the first few weeks.  After that time once a week will probably be adequate but can be checked using the finger test.  New plants will need to be watered throughout their first full year of growth, including the spring, summer and fall.  Late fall watering, until the ground is fully frozen, is essential for the survival of newly planted trees and shrubs.  Generally speaking, rainfall alone may not provide adequate moisture until after several growing seasons.

Mulching: Maintaining a 2-3” layer of organic mulch (such as our aged premium hardwood bark mulch) greatly reduces water loss to evaporation. It also reduces weeds, moderates soil temperatures and adds an aesthetic quality to the landscape.   Take caution to taper the bark away from plants, improper mulching can impair plant health and lead to plant decline or rot.  Mulch should be placed in a wide band, approximately 3 times the diameter of the root ball, over the root zone and no more than 3” thick.  Mulch piled up against the trunk may cause rotting of the bark and can create entry points for insect and disease organisms.  While there are many types of decorative mulches on the market we recommend untreated aged hardwood.  Under no circumstances should fresh mulch be mixed in with the soil.

Watering Guidelines for Perennials and Groundcovers

Groundcovers and Perennials:  Many groundcovers and perennials die because they receive too much or too little water. Groundcovers and perennials require moisture around the roots but should never be soaking wet.  A good water schedule especially for the first year is very important.  The general practice of infrequent and deep watering should always be followed.  Water deep to the root zone and let the area dry out again before watering    Use the finger test to see if water is needed.  On average a smaller newly planted perennial will require 2-3 gallons of water a week. Adequate soil moisture is essential for the first 2-3 weeks until the roots have time to grow out.   After that time water can be cut back. When watering, water the whole area and not just the individual plant.  Water early in the day, so foliage dries before nightfall.  This will help prevent fungal diseases from occurring.  Again use the finger test to make sure not to overwater and kill things.

Caution:  These are only general recommendations.  Each Site is different (i.e. soil type, sun, and wind exposure) and different plants have different water needs.  You must adjust your watering routine to compensate for those factors as well as the weather.  Be Careful not to over water A plant may also be “killed with Kindness” from over watering as easily as it may die from lack of water.  IF you are uncertain whether you are under or overwatering, call the Garden Center staff for advice.  Plants that die as a result of improper watering are not covered by the warranty. 

Mulching:  Use no more than 2” of well aged hardwood bark to mulch perennials and groundcovers.  Mulch should be tapered back from the base of the plant.  Mulch should not cover the base, stems or leaves of the plant.  This practice will cause plant rot.  Certain types of perennials such as Iris, Sedums and Lavender do not like hardwood mulch but prefer a grit, pea gravel or sand mulch.  If you have any more questions please do not hesitate to ask our staff!