Drip irrigation for trees and shrubs: placement, flow, bubblers

Short answer

Spread several emitters evenly within the tree's drip line, keep them above ground, and size the system for the mature tree in the hottest part of the year, as Utah State University Extension advises. No source gives a fixed number of emitters per tree. Bubblers put out far more water at one point than drippers do.

Picks that fitAll picks and how to choose

Raindrip PC8050B 2 GPH pressure-compensating dripper (50‑pack)Check price on Amazon
Rain Bird SW20‑30PS 2.0 GPH pressure-compensating spot watering emitter (30‑pack)Check price on Amazon
Rain Bird ILB4PKSX in-line full-circle bubbler on 5 in stake (4‑pack)Check price on Amazon

Where the emitters go

Utah State University Extension's tree guidance says to place emitters above ground and spread them evenly within the tree's drip line, the area under the outer edge of the canopy.^[1] It also says to design the system for the mature tree in the hottest part of the year.^[1]

That second point shapes the layout. A system sized only for today's small tree will fall short as it grows, so leave room in the tubing ring to extend it and add emitters later.

How many emitters?

USU's tree page gives placement, not a count, and no fixed flow or run time.^[1] Soil changes the answer. USU says soil texture controls how water moves through the soil, and suggests two emitters per perennial in sandy soil.^[2] DIG's FAQ says water goes straight down in sandy soil and is absorbed slowly in clay.^[3] That is the reason to spread several emitters rather than rely on one.

Above ground or under mulch

DIG recommends keeping drippers above ground or under mulch to prevent clogging, rather than burying them.^[3] USU's tree guidance also places them above ground.^[1]

Higher-flow options

Trees and large shrubs often need more water at each point than a bed of annuals. Makers sell several higher-flow devices.

Device	Flow the maker lists	Pressure	Note
Rain Bird PC on-line emitters	Nine flows, 0.5 to 24 GPH	Compensates 15-50 psi	Self-piercing inlet
DIG adjustable mini-bubbler	Up to about 31.5-32 GPH at 30 PSI	15-30 PSI	Adjustable; not called PC
Rain Bird 1300A-F bubbler	1.0 to 2.3 GPM	10-60 psi	Full circle; note GPM, not GPH

Rain Bird's PC on-line emitters run from 0.5 up to 24 GPH and compensate from 15 to 50 psi.^[4] DIG's adjustable mini-bubbler turns from full flow down to shut-off, works at 15 to 30 PSI, and its page does not call it pressure-compensating.^[5] DIG's page gives its top flow as both 31.5 and 32 GPH at 30 PSI, so treat it as about that.^[5]

Rain Bird's 1300A-F full-circle bubbler is in a different class: 1.0 to 2.3 GPM over 10 to 60 psi, set with a stainless-steel screw.^[6] One GPM is 60 GPH, so a single 1300A-F at its low setting puts out as much as dozens of 1 GPH drippers.

Bubbler or dripper for a tree?

A dripper puts a small flow into one spot. A bubbler floods a small area fast. Because bubblers use much more water, keep them on their own line or zone, the way Colorado State University Extension advises for micro-sprays.^[7] Raindrip says drippers should never be mixed with sprinklers on the same line.^[8] The sprays and bubblers guide covers zones and pressure.

Lawns stay on sprinklers

DIG suggests conventional pop-up sprinklers, not micro sprinklers or drippers, for lawns.^[3] If a tree stands in a lawn, its drip ring and the lawn sprinklers are two different systems.

How long to run it

DIG says run time and frequency depend on location, plants, soil type and weather, and advises checking the soil and plants and adjusting as needed.^[3] We give no schedule.

Emitters and bubblers that fit

Picks that fit6 products

For a ring of drippers, choose the Raindrip PC8050B 2 GPH 50-pack, the DIG B224B 4 GPH PC button 10-pack, or the Rain Bird SW20-30PS 2.0 GPH bag of 30 that pierces straight into 1/2 in or 3/4 in tubing (15-50 psi).

Drip emitters for trees and shrubs: placement, flow and bubblers