Drip irrigation for shrub beds: rows, rings and run times.
Shrubs do well on drip when they have a zone of their own and the line suits the bed. This guide helps you decide between rows across the bed and rings round each shrub, how far apart the lines go in your soil, and how long and how often to run the zone, new shrubs included.
Written for homeowners and estate and facility managers. Updated .
Key points
- Give shrubs a zone of their own, apart from the lawn's sprinklers, the trees and any bed of drought-tolerant plants.
- Lay dripline in rows across a closely planted bed, and give shrubs that stand apart a ring or an emitter of their own.
- Space the rows and drippers to suit your soil, and fit a filter and a pressure regulator after the zone valve.
- Water new shrubs on the root ball, little and often, until their roots grow out; then water less often and watch them.
- Walk the bed while the zone runs, flush the lines, and change the run time with the season.
On this page
A zone of their 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 a moderate rooting depth, between lawn grasses and trees.
Hunter's drip design guide gives each hydrozone its own valve, split by plant type, spacing, sun, exposure and slope: a shrub bed in full sun and one in shade are two zones. A shrub zone should never share its valve with:
- The lawn's sprays or rotors: the University of Florida advises against putting drip emitters on the same zone as either.
- Trees, which root deeper and, Hunter notes, can need more water than the plants around them.
- Low-water plants such as oleander or crown of thorns, which a moderate zone would overwater.
Home garden and lawn irrigation: splitting a garden into zonesLawn irrigation with sprays and rotorsTree irrigation with bubblers and dripDrought-tolerant bed 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), pages 10 and 19; Yasalonis, Dukes and Cardenas-Laihacar, University of Florida IFAS Extension (2017, revised 2025), Microirrigation or Drip Irrigation for Home Landscapes (AE524).
Shrubs for this zone
Shrubs for a moderate zone include, for example, hibiscus (Hibiscus rosa-sinensis), copperleaf (Acalypha wilkesiana), duranta (Duranta erecta), orange jessamine (Murraya paniculata) and ixora (Ixora coccinea). WUCOLS, the University of California's database of garden plants' water needs, rates the first four moderate in every region where it rates them, and ixora moderate to high.
Not every shrub belongs here. Oleander (Nerium oleander) and pride of Barbados (Caesalpinia pulcherrima), which the Federal University of Agriculture, Abeokuta, lists among ornamental shrubs, are rated low or very low in most WUCOLS regions, like bougainvillea and crown of thorns (Euphorbia milii). They need a drier zone.
A shrub's roots stay in its root ball at first, then grow out well past the edge of its leaves; once they have, the University of Florida says, shrubs cope well with drought. Hedges have a guide of their own.
Watering a hedge with dripline
Sources: University of California, Davis (2025), WUCOLS plant search database: ratings for Hibiscus rosa-sinensis, Acalypha wilkesiana, Ixora coccinea, Duranta erecta, Murraya paniculata, Nerium oleander, Caesalpinia pulcherrima, Bougainvillea and Euphorbia milii; Federal University of Agriculture, Abeokuta, HRT 507 Ornamental Horticulture lecture notes (Aiyelaagbe and Olosunde), page 3: ornamental shrubs; Gilman and others, University of Florida IFAS Extension (2009, reviewed 2024), Establishing Shrubs in Florida Landscapes (ENH1130).
How much water shrubs need
The daily need is worked out in two steps. The first is ETo, the weather's drying power: the water a well-watered field of grass would lose in your weather, in mm a day. One millimetre over one square metre is one litre; the crop guide explains more.
For a dry-season month in the north and centre of Nigeria, this series uses 6 mm a day. A field study at Afaka, Kaduna State, found monthly averages of 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 rainy-season guide shows how to count rain.
The second step is the plant factor, the share of ETo the plants need. California's rules give four classes: very low, under 0.1; low, 0.1 to 0.3; moderate, 0.4 to 0.6; high, 0.7 to 1.0. These shrubs are moderate, and the example below uses 0.5, picked from the middle of the class.
The classes come from California and are a guide only, not a Nigerian measurement: watch your shrubs and adjust.
Irrigating tomatoes, peppers and onions: ETo and crop factorsSupplemental 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.
Rows across the bed, or rings round each shrub
Dripline is pipe with drippers built in; the dripline guide explains it. A shrub bed takes it in one of two ways, both drawn below.
Where shrubs are planted close together, lay rows across the whole bed: Hunter calls this a simple way to water dense plantings. The rows run from a supply pipe on one side to a pipe joining their far ends, with a flush point at the end furthest from the supply. On a slope, run them across it, not down it.
Where shrubs stand apart, rows would mostly wet bare soil. Give each shrub a ring of dripline round its root ball, fed by plain pipe, or a single emitter of its own on a riser, a short upright pipe. Hunter puts the first ring near the root ball and more rings further out, within the spread the canopy will reach.
- Zone valve, then a filter and pressure regulator, in a valve box beside the bed
- Rows of dripline across the closely planted end of the bed, with drippers built in
- Flush point at the far end of the rows, opened to wash dirt out
- Shrub standing apart: a ring of dripline near the root ball, and a second ring under the canopy
- New shrub: a small ring right on its root ball, where all its roots still are
- Mulch over the soil and the lines
Drip tape or dripline: which suits your crop?Hunter HDL-PC driplineHunter HEB emitter, for a riserHunter PLD fittings, to join and branch dripline
Sources: Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 171, 188, 189 and 190; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 12, 14 and 19; Hunter Industries, HDL dripline: installation details HM.HDL.02 (planting bed, centre feed) and HM.HDL.12 (shrub ring).
Spacing by soil
Drippers are rated by their flow: how much water passes in a set time, in litres per hour (L/h) for a dripper, or cubic metres per hour (m³/h) for a pump or a pipe. One cubic metre is 1,000 litres.
Water spreads sideways further in clay than in sand, where it sinks fast, so drippers and rows go closer together in sand. The table gives Hunter's spacing, converted from inches and US gallons, and the nearest HDL-PC dripline in our store.
Not sure of your soil? Hunter says to use the closer spacing and the higher flow. Squeeze a moist handful: sand feels gritty and falls apart, loam forms a ball that crumbles, and clay is sticky and holds together.
On clay even the nearest line puts water down faster than the soil takes it in, so split each watering into shorter runs; the soils guide explains why.
| Soil | Hunter's guide: dripper flow and spacing | Rows apart | Nearest line in our store |
|---|---|---|---|
| Sandy | About 3.8 L/h every 30 cm | 30 to 45 cm | 3.8 L/h every 30 cm |
| Loamy | About 2.3 L/h every 45 cm | 40 to 55 cm | 2.4 L/h every 45 cm |
| Clay | About 1.5 L/h every 60 cm | 45 to 60 cm | 2.4 L/h every 45 cm, in short runs |
Watering sandy, loamy and clay soils
Sources: Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 8 and 9; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, page 172.
What the zone needs ahead of the line
Hunter starts every drip zone with a zone valve, a filter and a pressure regulator. Pressure is how hard the water pushes inside the pipe, measured in bar.
Filters are rated in mesh or microns: the higher the mesh, or the lower the microns, the finer the filter. HDL-PC needs water filtered to at least 120 mesh (125 microns). Hunter's HFR filter regulator filters to 150 mesh (100 microns) and lowers the pressure to 1.7 or 2.8 bar, depending on the model. It needs more pressure coming in: for Hunter's kit of a valve and filter regulator, about 2.3 to 2.8 bar for the 1.7 bar model and 2.8 to 4.1 bar for the 2.8 bar one, depending on the flow.
The line is pressure-compensating (PC): each dripper gives the same flow anywhere between 1 and 4.2 bar, so the far end of the bed gets as much as the near end.
Add a flush point at the far end of the lines, a valve or cap you open to wash dirt out, and an air relief valve at the highest point. Each line has a maximum length, covered in the hedge guide.
Lay the line on the soil under mulch, staked about every 1.5 m and near each fitting, a little slack rather than stretched.
Hunter PGV zone valveHunter HFR filter regulatorChoosing a drip irrigation filterWatering a hedge with dripline: length limits and feeding from the middle
Sources: Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 10, 11, 22 and 27; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 168, 169 and 172; Hunter Industries, HDL dripline: installation details HM.HDL.04 (dripline below mulch) and HM.HDL.12 (shrub ring); Yasalonis, Dukes and Cardenas-Laihacar, University of Florida IFAS Extension (2017, revised 2025), Microirrigation or Drip Irrigation for Home Landscapes (AE524).
How long to run the zone
For rows across a bed, the run time comes from the rate they put water down: the dripper's flow divided by the dripper spacing times the row spacing.
Water early in the morning, which Hunter's residential guide gives as the calmest time, with the least lost to evaporation.
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 (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 20 and 25; Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), page 26.
New shrubs, and what else changes the time
A new shrub's roots stay inside its root ball for the first few weeks. University of Florida research advises watering the root ball and the soil just round it, little and often, and Hunter says newly planted shrubs need water every day or two.
So check that a dripper sits on or beside each new root ball; with rings, the first ring goes near it, as drawn.
Roots take months to grow out, about 6 to 12 months in most of Florida. After that, Hunter advises deeper, less frequent watering, such as two days' water every second day, still in short runs. If established shrubs wilt, water before the leaves die, as the University of Florida advises. Two other things change the time:
- Soil: Hunter waters sandy soil on more days a week and clay on fewer, in shorter runs. The soils guide explains why.
- Season: the dry-season guide covers the dry months, and the rainy-season guide how much rain to count.
Watering sandy, loamy and clay soilsPlanning dry-season irrigation in NigeriaSupplemental irrigation in the rainy season
Sources: Gilman and others, University of Florida IFAS Extension (2009, reviewed 2024), Establishing Shrubs in Florida Landscapes (ENH1130); Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), page 26; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), page 19.
Signs and checks
- Run the zone and walk the bed: each dripper should leave a damp patch of about the same size. A much bigger one is a leak; a dry gap, a blocked dripper or kinked line.
- Wilting shrubs, new ones above all, are short of water: check the zone ran, then lengthen the run a little.
- Soil that stays soggy, or water running off, means the run is too long for the soil: shorten it or split it.
- Clean the filter, then open the flush point and run the zone until the water comes out clear, at least once a year and after any repair.
- After weeding or trimming, check the lines are still staked under the mulch and uncut: tools and machines damage the small plastic parts.
Irrigation maintenance through the seasonSeven causes of drip irrigation failure
Sources: Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 19, 23, 25 and 26; 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).
When to ask for a design
Ask for a design when the beds are large or many, the ground slopes, the water carries sand, or you do not know your supply's pressure or flow. Send us:
- A sketch or photos of the beds, with rough sizes and where sun and shade fall.
- The shrubs, how far apart they are planted, which are new, and your soil if you know it.
- Where the water comes from, with a pressure reading or the pump's details.
- Any slope, and where the valves and controller could go.
Trademarks belong to their owners. ASFA IRRIGATION NG LIMITED is an independent company; no partnership is implied.
Landscape irrigationGarden products in the storeRequest a quote
Planning drip for your shrub beds?
Send us a sketch or photos of the beds and tell us where the water comes from. We design and supply garden systems, and installation can be quoted.