Key points

Water a hedge on a zone of its own: one line can do for a narrow, young hedge, and two suit a wide or double row.
Feed a long hedge from the middle, keep each half within the dripline's length limit, and put a flush point at each end.
Keep the lines at the foot of the hedge under mulch, staked down and clear of the trimmers and the mower.
Work out the water per metre of hedge, and expect a hot wall or a windy boundary to dry it faster.
Walk the hedge while the zone runs: a dry end, a wet patch or a cut line each have a simple check.

On this page

A hedge is a zone of its own

A hydrozone is a group of plants with similar water needs and rooting depth, in similar sun and soil, watered together on one valve with its own run time. California's landscape water rules give shrubs, and so hedges, a moderate rooting depth.

Hunter's drip design guide gives each hydrozone its own valve, split by plant type, spacing, density, sun, exposure and slope. A hedge differs from a bed: its plants stand close in one line, often along a wall, a drive or an open boundary. Unless it matches a nearby bed in plants and sun, give it a zone of its own, and never put it on the lawn's sprays or rotors, which the University of Florida advises against mixing with drip.

Drip irrigation for shrub beds: zones and plants Home garden and lawn irrigation

Sources: California Code of Regulations, Title 23, section 490.2 (2025), Model Water Efficient Landscape Ordinance: definitions of hydrozone and plant factor; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), page 10; Yasalonis, Dukes and Cardenas-Laihacar, University of Florida IFAS Extension (2017, revised 2025), Microirrigation or Drip Irrigation for Home Landscapes (AE524).

Hedge plants and their water

The ornamental horticulture course of the Federal University of Agriculture, Abeokuta, describes a hedge plant as well branched, evergreen, perennial and easily kept in shape, and gives croton (Codiaeum variegatum), orange jessamine (Murraya paniculata), duranta (Duranta erecta, also called Duranta repens) and ixora as examples. A survey of the plants on the Lagos State University campus at Ojo counted orange jessamine more often than any other, followed by weeping fig (Ficus benjamina) and ixora.

WUCOLS, the University of California's database of garden plants' water needs, rates orange jessamine, duranta and weeping fig moderate in every region where it rates them, and ixora moderate to high; it does not list croton. California's rules put the moderate class at a plant factor of 0.4 to 0.6: the share of the weather's drying power the plants need. This guide's example uses 0.5, picked from the middle of the class.

The drying power, ETo, is the water a well-watered field of grass would lose in your weather, in mm a day; the crop guide explains it. This series uses 6 mm a day for a dry-season month in the north and centre: a field study at Afaka, Kaduna State, found about 5.5 to 6.6 mm a day from December to March, and FAO gives 6 to 7 mm a day for a semi-arid climate at 15 to 25°C. The south and the rains run lower.

The classes come from California and are a guide only: watch the hedge and adjust.

Irrigating tomatoes, peppers and onions: ETo and crop factors Supplemental irrigation in the rainy season

Sources: Federal University of Agriculture, Abeokuta, HRT 507 Ornamental Horticulture lecture notes (Aiyelaagbe and Olosunde), page 2: hedges and screens; Adu, Sharaibi and Aderinola (2017), Inventory and ethnobotanical assessment of plant species in Lagos State University, Ojo campus, Lagos, Nigeria, Journal of Medicinal Plants for Economic Development 1(1): abstract; University of California, Davis (2025), WUCOLS plant search database: ratings for Murraya paniculata, Duranta erecta, Ficus benjamina and Ixora coccinea; California Code of Regulations, Title 23, section 490.2 (2025), Model Water Efficient Landscape Ordinance: definitions of hydrozone and plant factor; Onwuegbunam and others (2025), Actual crop coefficients and yield response factors of irrigated tomato in Afaka, Northwest Nigeria, Journal of Applied Life Sciences and Environment 58(1): study location and Tables 1a and 1b; FAO (1986), Irrigation Water Management Training Manual No. 3: Irrigation Water Needs, chapter 3, Tables 5, 6 and 14.

One line or two

Dripline is pipe with drippers built in; the dripline guide explains it. Each dripper's flow is how much water passes in a set time, in litres per hour (L/h); for a pump or a pipe it is given in cubic metres per hour (m³/h), and one cubic metre is 1,000 litres.

Hunter's installation detail for a hedge row lays two lines, one along each side of the row of plants, with the drippers staggered between them for even coverage. Set the gap between the lines as for a bed: the shrub-bed guide gives row and dripper spacing by soil.

A narrow or young hedge can start with one line run along the plants: Hunter calls laying dripline through a series of plants an accepted method, as long as there are drippers near each plant. A wide hedge or a double row needs two lines, or more. Either way, keep the lines under the hedge, where its roots are, not along the foot of a wall or out at the lawn edge.

Drip tape or dripline: which suits your crop?Drip irrigation for shrub beds: spacing by soil Hunter HDL-PC dripline

Sources: Hunter Industries, HDL dripline: installation detail HM.HDL.11 (hedge row); Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 171 and 172.

How long one line can run

Pressure is how hard the water pushes inside the pipe, measured in bar. HDL-PC is pressure-compensating (PC): each dripper gives the same flow anywhere from 1 to 4.2 bar. Even so, a line has a length limit, past which Hunter says it cannot supply all its drippers, and the limit depends on the pressure where the line starts.

Read the row at or below your pressure: after a filter regulator set to 1.7 bar, use the 1 bar row, and at 2.8 bar the 2 bar row. A line that turns a corner or branches counts every branch in its length.

Pressure where the line starts	2.4 L/h every 30 cm	2.4 L/h every 45 cm	3.8 L/h every 30 cm
1 bar	71 m	96 m	52 m
2 bar	104 m	142 m	77 m
3 bar	124 m	170 m	92 m
4 bar	140 m	190 m	103 m

Hunter HDL-PC dripline Hunter HFR filter regulator

Sources: Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 169 and 172; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 12 and 15.

Feed it from the middle, flush at both ends

Feeding the lines from the middle halves the length each side must carry. Hunter recommends a centre feed for long, narrow strips, with each side kept within the maximum length. So a 2.4 L/h line with drippers every 30 cm, at 1.7 bar, can run 71 m from one end, or 71 m each way from the middle.

Every drip zone needs an outlet at each far end so dirt can be washed out. On a hedge fed from the middle that means both ends: join the two lines at each end and fit a valve or a screw cap there that you can open. On a slope, Hunter zones the top, the slope and the bottom separately, so ask for a design.

Ahead of the lines go a zone valve, a filter and a pressure regulator, as the shrub-bed guide explains.

Zone valve, then a filter and pressure regulator, in a valve box
Supply pipe to the middle of the hedge, so each half of a line is shorter
Two driplines, one on each side of the plants, with the drippers staggered
Flush point at each end, opened to wash dirt out of the lines
Boundary wall: its heat and reflected sun can dry the hedge faster
End-on view: the lines at the foot of the hedge, under mulch, back from the trimmed face

A long hedge fed from the middle: two lines, one on each side of the plants, a flush point at each end, and the lines under mulch at the foot of the hedge.

Drip irrigation for shrub beds: the valve, filter and regulator Hunter PLD fittings, to join and branch dripline

Sources: Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 11, 13, 16 and 17; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 172 and 179; Hunter Industries, HDL dripline: installation detail HM.HDL.02 (planting bed, centre feed).

Walls, wind and trimmers

Walls, paving and drives reflect sun and heat, and an open boundary catches the wind, all of which raise plants' water use, as Hunter's drip guide notes. The University of Florida lists the western side of a building, closely spaced plants, an exposed, windy spot and a small planting space among the things that raise shrubs' water needs, even once established. A hedge often has several, so when it looks dry, check the wall side and the ends first.

Mowers and trimming tools damage the small plastic parts of drip systems. Lay the lines on the soil under mulch, at the foot of the hedge and back from the trimmed face, and stake them down about every 1.5 m and near each fitting.

A new hedge is a row of new shrubs: until their roots grow out of the root balls, each needs a dripper on it. The shrub-bed guide explains how often to water them.

Drip irrigation for shrub beds: new shrubs

Sources: Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 12 and 27; Gilman and others, University of Florida IFAS Extension (2009, reviewed 2024), Establishing Shrubs in Florida Landscapes (ENH1130); Yasalonis, Dukes and Cardenas-Laihacar, University of Florida IFAS Extension (2017, revised 2025), Microirrigation or Drip Irrigation for Home Landscapes (AE524); Hunter Industries, HDL dripline: installation details HM.HDL.04 (dripline below mulch) and HM.HDL.11 (hedge row).

Litres per metre of hedge

For a hedge, the useful figure is litres per metre a day, because the lines run along it. Each metre of hedge draws on its width times one metre of soil, and 1 mm of water over 1 square metre is 1 litre.

Water early in the morning, which Hunter's residential guide gives as the calmest time, with the least lost to evaporation.

Worked example, for illustration only

A 60-metre hedge along a boundary wall in a dry month

Assumptions

ETo of 6 mm a day and a plant factor of 0.5, picked from the middle of the moderate class for this example (above).
Drip gets about 90 percent of the water to the roots, FAO's indicative figure for drip.
The hedge is 1 metre wide, so each metre of it draws on about 1 square metre of soil.
Two lines of HDL-PC with 2.4 L/h drippers every 30 cm, fed at the middle through a filter regulator set to 1.7 bar.

Working

Water the hedge uses: 6 mm × 0.5 = 3.0 mm a day, or 3.0 litres on the square metre under each metre of hedge.
With drip losses: 3.0 ÷ 0.9 = 3.3 litres per metre of hedge a day.
What the lines give: each has 1 ÷ 0.3 = 3.3 drippers a metre, so 3.3 × 2.4 = 8 L/h a metre, and two lines give 16 L/h a metre.
Run time: 3.3 ÷ 16 = 0.21 hours, about 12.5 minutes a day, set as two runs of about 6 minutes, since Hunter advises splitting drip runs over 12 minutes. One line alone would need 25 minutes.
Length: fed at the middle, each line runs 30 m each way, well inside the 71 m of the 1 bar row.
Flow for the zone: 2 lines × 60 m × 8 L/h = 960 L/h, or 16 litres a minute, inside the 2 to 55 litres a minute Hunter gives for its kit of a valve and filter regulator.

Result: In this example the hedge needs about 3.3 litres per metre a day, which two lines give in about 12.5 minutes, and the supply must keep up about 1 m³ an hour while the zone runs. A hedge 1.5 m wide would need half as much again.

Watering sandy, loamy and clay soils Planning dry-season irrigation in Nigeria Supplemental irrigation in the rainy season

Sources: Onwuegbunam and others (2025), Actual crop coefficients and yield response factors of irrigated tomato in Afaka, Northwest Nigeria, Journal of Applied Life Sciences and Environment 58(1): study location and Tables 1a and 1b; FAO (1986), Irrigation Water Management Training Manual No. 3: Irrigation Water Needs, chapter 3, Tables 5, 6 and 14; California Code of Regulations, Title 23, section 490.2 (2025), Model Water Efficient Landscape Ordinance: definitions of hydrozone and plant factor; FAO (1989), Irrigation Water Management Training Manual No. 4: Irrigation Scheduling, Annex I, Table 8; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 168 and 172; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), page 25; Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), page 26.

When the hedge looks wrong

One end drier than the other: measure each line from where it is fed, branches included, and compare it with the table. If it is too long, feed it from the middle or split the zone.
Dry patches along a line: run the zone and look for drippers that do not wet. Clean the filter, then open the flush points and run until the water comes out clear; do this at least once a year.
A soft, wet patch or water bubbling up: a cut line or a pulled fitting. Cut out the damaged piece, flush the line from both sides, and rejoin it with a barbed connector.
The wall side drier than the front: check its line is under the hedge and wetting, then lengthen the run a little if needed.
Soil still soggy a day after watering: the run is too long for the soil. Shorten it, or split it into two runs.
Lines showing after trimming or weeding: push them back under the mulch and re-stake them.

Irrigation maintenance through the season Seven causes of drip irrigation failure Choosing a drip irrigation filter

Sources: Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 12, 23, 25 and 26; Yasalonis, Dukes and Cardenas-Laihacar, University of Florida IFAS Extension (2017, revised 2025), Microirrigation or Drip Irrigation for Home Landscapes (AE524).

When to ask for a design

Ask for a design when the hedge is longer than the table allows from one feed, turns corners or climbs a slope, has more than one row, or you do not know your supply's pressure or flow. Send us:

The hedge's length and width, and whether it is one row or two.
What it grows against: a wall, a fence or an open boundary, and which way it faces.
The plants, and whether the hedge is new.
Where the water comes from, with a pressure reading or the pump's details.
Any slope, and where the valve could go.

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Watering a hedge with dripline: lines, long runs and run times.