Watering Triage: What to Water First and What Can Wait

When summer’s dry heat arrives, plant demand for water goes up. Fail to deliver, and the result is a landscape full of wilting or dead plants.

On the other hand, unsustainable water bills, the prospect of running a well dry, or just a lack of time to keep up with unrelenting hose demands can make it difficult to keep up. At some point, gardeners may need to “triage.”

Triage is that tough decision that divides plants between ones that need water now to stay alive vs. those that can risk delay – or go without. If you can’t water everything, a sensible strategy is to focus limited water and time on the plants that are most valuable to you. That could be the costly new tree or bed full of shrubs that landscapers just installed in May, but it also could be sentimental-value plants, such as that irreplaceable peony division handed down from Grandma or a rare heirloom tomato variety. Either way, a good question to ask is, “Which plant losses would hurt most if I don’t water?”

New vs. established plants

Keep in mind that any new plant is more at risk of drought injury or death than established ones. Even drought-tough species aren’t very drought-tough until their roots occupy enough ground to mine what moisture they need to survive.

Most perennials and ornamental grasses are in reasonably good root shape after two years in the ground. Trees, shrubs, and evergreens can take three to four years to adequately root-establish. The upshot is that a five-year-old magnolia might be able to go weeks without water while the same variety in the same spot might need a soaking twice a week if it was just planted this spring or last fall.

Watering the lawn

The same is true for lawns. Turfgrass that’s two or more years old generally can go a month without water even after it goes brown and dormant. Established lawns usually can go to the bottom of the triage list, especially since lawn irrigation requires a lot of water.

However, new grass that’s less than a year old will die sooner due to its limited root system. Since replacing a whole lawn is expensive and labor-intensive, a new one might rate high placement.

Annuals vs. perennials

Another low-on-the-list possibility involves annual flowers, container plantings, and vegetables. Most of these are going to die come frost or the end of the season anyway. If you can live with the possibility that your petunias and zinnias might croak in August instead of October, then those are candidates to go off hose-fed life support.

Container plants need water every day or two in hot weather, so unless you really need them to the bitter end, they’re also sacrificial candidates. And although it’s not easy to walk away from wilting peppers or tomatoes in their prime, at least you can divert would-be water expenses into grocery-store substitutes.

7 Signs of Water Trouble

Most plants warn when they’re running into drought stress.

  1. Wilting. Wilting that doesn’t fix itself in the cooler, darker conditions overnight is one of the first signs of water stress.
  2. Color loss. A second dry-soil indicator is when plants begin to lose their vibrant color. For example, evergreen needles may turn a duller green, while perennial and tree leaves might start to yellow.
  3. Curling leaves. Leaves that curl upward are a third sign that plants are trying to conserve moisture. Curled leaves are a plant’s way of trying to limit evaporation loss by exposing less surface area to wind and light.
  4. Slowed growth. Although it’s a little more subtle, slowed or no growth is another ploy in a plant’s bag of survival tricks. Look for leaves that are no longer expanding or the lack of new and/or extending shoot tips.
  5. Browning. Less subtle and more serious, though, is when existing foliage starts to brown around the tips and margins. That’s a sign that damage is already taking place.
  6. Dropping leaves. The next stage of trouble is when plants begin dropping foliage as a way of getting rid of their main moisture-losing parts. For perennials and leaf-dropping (deciduous) woody plants, that’s not a good thing but maybe not fatal – if you get them water ASAP. However, for needled evergreens, by the time needles are brown and dropping, the plant is likely already dead.
  7. Dying roots & branches. The last-gasp stage is when roots and whole branches start to die. Even a good soaking may be too late by then to make a difference.

More watering tips

When you’re in triage mode, try dividing the yard into zones. Instead of watering the whole yard full of plants every few days, break up the job by watering one zone one day, then another zone another day – focusing just on the plants most in need.

Read more tips on watering efficiently.

Read about eight myths to avoid when watering your plants.

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