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HOW MUCH SHOULD YOU WATER YOUR SHRUBS AND TREES

 

This question is the mostasked in Nurseries today.  Without adequate questioning of the customers soilcondition, type of emitters and plant variety, any answer provided has littlechance of being correct. This Star Note discusses Shrubs and Trees, NOT Lawns.

 

Note: Lawn wateringis covered in Star Note # 900B

 

The SNWA Watering Guide & Restrictions

Frequency of Watering vs. Quantity of Water

How OFTEN should you water yourshrubs and trees (chart included)

How MUCH should you water yourshrubs and trees (chart included)

Soil type

Location

Cover under canopy of plant

Different Seasons

Bedding plants and vegetables

Consider switching to soaker lines

Shrubs and trees have deeper roots

Desert plants

Container plants

 

 

The SNWA WateringGuide  Plant Watering is covered by the Watering Guide orDrought Watering Restrictions Guide published by the Southern Nevada WaterAuthority (SNWA) and available at any Star Nursery location. The DroughtWatering Restrictions assign specific days for shrub and tree irrigation inwinter, spring and fall. During summer only 3 days a week is recommended. Thisguide offers additional suggestions for seasonal watering of desert andtraditional plants.  Ask for a copy at any Star Nursery location.  Rememberthat watering frequency and duration is based on many variables.  Things liketime of year, soil type (sand, clay or loam) and plant location (sun, shade orslope) all play a part in your decision.  For best results, get in touch withyour soil and experiment!  An inexpensive Moisture Meter (available at all StarNurseries) is a great help in determining content and distribution of water.  (top)

 

Frequencyof Watering vs. Quantity of Water. Know the difference.Days per week represents “frequency”, while “minutes of run time” representsquantity. Change your frequency of watering throughout the seasons, and attemptto leave the minutes unchanged.

 

The followingrecommendations for appropriate typical watering amount and frequency are notspecific guidelines. These are provided to the reader as a convenience, inorder to compare typical with their individual situation. Soil, Sun, Slope andPlant type differ greatly, and so will water requirements.  Star Nursery understandsthat our customers are only looking for a starting point and general guidelinesfor watering. We only seek to satisfy this request, while providing somebackground information regarding various landscape environments and planttypes.  (top)

 

HOW OFTENSHOULD YOU WATER YOUR SHRUBS and TREES ?

 

These recommendations areonly typical – Conditions may differ for individual landscapes.

Please consult with aqualified professional to make certain proper watering is selected for yourlandscape.

Typical  watering frequency

Winter       

Spring – Fall

Summer

Bedding plants and vegetables.

Once per week

Twice per week

Three times per week

Trees

Twice per month

Once per week

Twice per week

Shrubs

Once per week

Twice per week

Three times per week

Desert Plants

Once per month

Twice per month

Once per week

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HOW MUCHSHOULD YOU WATER YOUR SHRUBS and TREES

(how many minutes / gallons)

Remember “how manyminutes” varies with the emitter you use.  Most are rated in gallons per hour,so for convenience…

This chart will use a “onegallon per hour” drip as example to determine minutes.

Please consult with aqualified professional to make certain proper watering is selected for yourlandscape.

 

Typical Watering Amount

Winter

Spring – Fall

Summer

Bedding Plants and Vegetables

20-30 minutes

30 minutes

45 minutes

Trees (1 emitter* per sq. yd.**)

1-2 hour

2 hours

2 hours

Shrubs (1 emitter* per foot in size***)

45 minutes

1 hour

1 hour

Desert Plants (1 emitter* per 2 foot size)

45 minutes

1 hour

1 hour

*With all your trees, shrubs and desert plants larger than 1 foot in height, youshould have a minimum of 2 drips on each plant. This makes certain that youhave adequate coverage around the root system, and not just on one side.

 

**“per sq. yd.” refers to the area beneath the trees’ canopy. A tree with acanopy that spread 10 ft. in width would have approximately 9 sq. yd. rootarea. Check with our Nursery Advisors if you need help calculating.

 

***“per foot in size” refers to the height or width of a shrub, which ever isgreater.

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Soil type.  Clay, sand and loam all have different waterholding capacities and drainage rates. Most of the landscapes in Las Vegasare very slow to drain, but not all!   Know the characteristic of your soil,and in particular the soil where you intend to plant.  Slow draining soilsshould be watered ‘less often’.   (top)

 

LocationOna slope ?  Some slopes will drain quite a bit faster, while others (due toclay) do not.  Does water run to this location, or away from it.  Does thisarea get extreme heat and reflected sun in the summer ?  All of these thingwill affect water requirements.  If plants in a unique location do not have adifferent zone or valve than the other, you will very likely have a hard timekeeping them all healthy.

 

Cover undercanopy of plant.  Mulch insulates the soil and keeps it from dryingout as quickly as it would under normal conditions.  Proper use of mulch can minimizethe water frequency requirements.  (top)

 

DifferentSeasons.  Plants need water less often in the wintermonths. Most often in the summer.  Try to leave the quantity of water, orminutes you run your drips, nearly constant throughout the year. This helps tokeep salts build-up to a minimum, and helps to develop deeper roots.

 

 

Beddingplants and vegetables areoften on the same zone as the lawn and so watered the same as lawn.  If thisworks for you and you’re happy with the results, then stick with it. If youdon’t have excellent drainage in your beds, frequent watering will cause thesoil to become soggy causing chlorosis and root rot. Overhead sprays will causeproblems like misshapen fruit, blossom rot, stem rot, leaf spot and otherfungus problems, especially in hot weather.  It also encourages plant pestslike aphids.  Plants with large leaves may shed the water and prevent the rootsfrom getting a sufficient amount of moisture.  (top)

 

Considerswitching to soaker lines,drip or bubbler irrigation.  Consult our Certified Nursery Advisors forspecific information depending on your situation.  In any event, applying waterdirectly to the root zone and using surface mulches will reduce watering frequencyfor most flowers and vegetables. Winter flowers need even less since soilevaporation is greatly reduced by colder temperatures.  Keep your soil evenlymoist for the first few weeks after planting so these shallow-rooted plants canbecome established.

 

Shrubs andtrees have a deeper, moreextensive root system and different water requirements.  If possible have themon a different valve or time zone in your irrigation system.  Sprinklers canwork but drip irrigation is a much more efficient and less costly way to carefor your landscape plants.  A good rule of thumb is 1-2 gallons of water forsmaller accent plants, 3-5 gallons for larger shrubs and 10 gallons of waterfor a 15 gallon plant each time you water.  Boxed trees will need even more waterbut it doesn’t have to be applied every day.  Consult StarNote 001, PlantingGuide, for new plants.  For established plants, once a week should besufficient (twice a week in summer).   (top)

 

Desertplants need thorough, widely spaced watering to look theirbest.  Follow StarNote 001 to establish new plants and use the same amountsrecommended for shrubs and trees above.  When established, once a week, evenless in winter, will work well for most desert trees and shrubs.  Cacti needwater even less often.  A good soaking every 2 weeks should be sufficient. Don’t water landscape cactus at all from mid November through February. 

 

Containerplants have small amounts of soil and generally need morewater than those in the landscape, especially during our hot summers.   Ifwatering by hand, keep a close watch on your plants.  Low humidity and hotwinds dry them out quickly.  A one-inch layer of bark or coarse mulch willconserve moisture in these conditions.  On the other hand, empty your saucersand drain trays.  If the pot remains in standing water, the soil will becomewaterlogged and your plant will suffocate.  Drip emitters and soaker lines canbe adapted to hose bibs on porch or patio and do a good job on containerplants.  See a Star Nursery irrigation consultant for details.

 

As you can see, wateringin desert climates is not an exact science, nor is it as simple as it mightseem.  Understanding the water needs of different plant groups and the natureof your soil will help you be successful.  Lastly, please choose the rightirrigation system for your landscape and learn how to run it correctly.  Don’tlet it run you!

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