Watering New Desert Plants in Surprise
Surprise publishes a week-by-week watering plan for new desert plants. Set a separate drip station, stretch the interval and move emitters as roots grow.
Irrigation Guides5 min read
New desert-adapted plants need water far more often than established ones. The City of Surprise guideline starts at every 1 to 2 days in the summer for the first two weeks and stretches the interval over eight weeks. After week eight, keep stretching the interval and move drip emitters to the outer edge of the root ball. Treat it as guidance and check the soil.
Why new plants break the regular schedule
An established desert shrub has roots spread well beyond its canopy. A new one has only the soil inside its nursery root ball. That small volume dries out quickly, especially in summer, even while the soil around it stays damp.
University of Arizona Cooperative Extension, in its Care of Desert-Adapted Plants publication, says that even plants that can eventually live on rainfall need supplemental irrigation for at least one growing season, and that establishment takes roughly two to three years. The City of Surprise uses a shorter working definition in its own table: one year for shrubs and three years for trees.
This is why a new plant on the same drip line as mature shrubs is hard to water well. A schedule that keeps the new plant alive will overwater the established ones.
The city's week-by-week guide
The Landscape Watering Guidelines page includes a separate table for newly planted desert-adapted plants. It gives days between waterings by week and by season:
| Weeks since planting | March to May | May to October | October to December | December to March |
|---|---|---|---|---|
| Weeks 1 and 2 | 3 to 4 days | 1 to 2 days | 3 to 4 days | 3 to 4 days |
| Weeks 3 and 4 | 6 to 7 days | 3 to 4 days | 6 to 7 days | 6 to 7 days |
| Weeks 5 and 6 | 7 to 10 days | 4 to 6 days | 7 to 10 days | 7 to 10 days |
| Weeks 7 and 8 | 10 to 14 days | 7 days | 10 to 14 days | 10 to 14 days |
The note under the table says that after week eight, you should gradually extend the time between irrigations until the plants are established, and move the drip emitters to the outer edge of the root ball. It adds that high-water-use plants may need more frequent watering.
The summer column is the steep one. A shrub planted in June starts at every one or two days. The same shrub planted in November starts at every three or four.
Choosing when to plant
Extension describes late fall as the ideal planting time for most desert plants, except frost-sensitive species, because the soil is still warm while the air cools, which encourages root growth. Late spring also works, with slower establishment. In Surprise terms, a fall planting starts on the gentler side of the city table and reaches week eight before the next summer.
How deep each watering should go
Frequency is only half the guide. The note under the new-plant table repeats the depth targets: 24 to 36 inches for trees, 18 to 24 inches for shrubs, and 8 to 12 inches for groundcovers, vines, cacti, succulents and annuals.
The Arizona Municipal Water Users Association puts the early goal more simply: each irrigation should wet the root ball and one to two inches of the soil around it. Check after a cycle by pushing a probe or long screwdriver into the soil at the root ball and just outside it. If the root ball is dry while the gravel on top looks wet, the emitter is in the wrong place or running too briefly.
Moving emitters as the plant grows
A new plant's emitter belongs over the root ball, because that is where the roots are. As roots grow out, water at the trunk becomes less useful. The city's note says to move emitters to the outer edge of the root ball after week eight. Extension goes further for the long term: a mature root zone spreads one and a half to four times the width of the canopy, so add emitters at and beyond the dripline as the plant matures. It also notes that sandy soils need emitters spaced more closely than clay soils because the wetted area is narrower.
Plan for that growth when the line goes in. Leave slack in the tubing, or run a loop around the plant, so emitters can be moved outward without splicing.
Give new plants their own station
The cleanest setup is a separate valve for new plantings, or at least for a group planted at the same time. The city guidelines say to water turf, planters, trees and shrubs separately, and new plants are a group of their own for their first season. When the plants reach the established intervals, that station can be reprogrammed or the plants moved onto the main shrub line.
Watch for both kinds of stress. Extension lists wilted, curled or drooping leaves and yellowing or dropping older leaves as signs of too little water, and soft tissue, wilted tips, algae or mushrooms as signs of too much.
Next step in Surprise
If new plants share a line with established shrubs, or emitters still sit at the trunk years after planting, see drip irrigation in Surprise. The drip irrigation page explains the work, and the Surprise service area page and all irrigation services list related help. Related reading: Reading the Surprise Landscape Watering Guidelines and Caliche, Drainage and Irrigation in Surprise.
FAQ
How often should I water a new desert shrub in a Surprise summer?
- The city's guideline for newly planted desert-adapted plants gives every 1 to 2 days in weeks one and two from May to October, then every 3 to 4 days, every 4 to 6 days, and every 7 days by weeks seven and eight. It is guidance, so check soil moisture.
What should I change after the first eight weeks?
- The city says to gradually extend the time between waterings until the plants are established, and to move drip emitters to the outer edge of the root ball. The city treats shrubs as established after one year and trees after three, when the regular seasonal table applies.
Can new plants share a drip line with established shrubs?
- They can, but it is hard to water both well. New plants need water much more often than established ones, so one shared schedule either stresses the new plants or overwaters the old. A separate valve for new plantings lets each group follow its own interval.
How far out should drip emitters go on a mature plant?
- University of Arizona Cooperative Extension says a mature root zone spreads one and a half to four times the canopy width, and recommends adding emitters at and beyond the dripline as the plant grows. Sandy soils need emitters spaced more closely than clay soils because water spreads less sideways.
What is the best time of year to plant in Surprise?
- Extension describes late fall as the ideal planting time for most desert plants, apart from frost-sensitive species, because warm soil and cooler air encourage roots. On the city's new-plant table, a fall planting starts at every three to four days rather than the summer's one to two.
Sources
- Care of Desert-Adapted Plants extension.arizona.edu
- Landscape Watering Guidelines surpriseaz.gov
- Arizona Municipal Water Users Association amwua.org