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Great Gardenening: Proper watering methods key to survival of plants, bushes

“Look at this shrub (or perennial) that you sold me. It just died. I’m so disappointed.”

Every landscaper, nursery person or garden center worker has heard words like that. We mostly know exactly what has happened by looking at the roots. (Disclaimer: I wrote “we” because sometimes I’m hearing the complaint too.) Reality is that this spring has been terribly dry, following a dry fall, and the root systems of many plants just dried up. Meanwhile, the homeowner says – and really believes – that he or she watered, sometimes adding “every day, too!”

After a good conversation about the amount and kind of watering it actually takes to make up for the rainy spring that never happened, many gardeners and homeowners come to understand how the plant died. Most of the time though, the conversations aren’t that thorough – it’s a busy time of year – leaving the customer, the landscape professional or both dissatisfied.

Landscaper’s lament

I asked a fellow CNLP, Chris Zeisz, a leader of Plant WNY (Professional Landscape and Nursery Trades association), affiliated with Russell’s Trees and Shrubs, what are some consumer misconceptions about watering that get them and their landscapes into trouble. He quickly responded with three often heard statements:

Fallacy: Oh, it was planted three years ago. It doesn’t need watering.

Correction: Cornell University’s woody plants department staff teach master gardeners and CNLPs in training that a tree or shrub planted in the last three (to five or more) years needs supplemental watering until it is established. How much water varies according to plant size, species, site, climate and soil – but typically five to 15 gallons a week might be what’s needed.

Fallacy: It rained last night; we’re off the hook.

Correction: We rarely know how much rain reached the plant roots. The amount is usually nothing like the inch or more the plants should get every week in the growing season. To measure an inch, use a rain gauge or cat food cans (about an inch deep). Then sometime dig near your treasured little tree to see how far an inch of rain penetrated. Unless it’s ideal soil, I’m betting that even an inch of rainfall did not reach the roots, most of them 12 to 18 inches below ground.

Fallacy: We have a sprinkler system.

Correction: Well ... there are sprinkler systems and sprinkler systems. Some are designed and placed by professionals who understand plants, and I do see wonderful results with excellent systems. I also see others. Is your system getting the water to the plants that need it? (Again, dig to check delivery to the roots.) Who set the timing and amount of flow? I hear from other professionals that the most common error with sprinklers is setting them for daily watering. The rule is: Water deeply – to where the roots are – not daily. That is because daily use never gets the water to the root level of the largest plants and it encourages shallow root systems.

Still, neither Chris nor I nor other professionals blame consumers for every plant that died. Frankly it’s not easy getting a new tree or shrub to survive its first years in the soil. We expect a few losses. But when a plant dies in my yard I figure I didn’t do an ideal job of planting, or amending the soil or ensuring decent drainage (they die from sitting in water too), or getting enough water to it at just the right time. Or winter was too harsh for the baby root system. The highest risk of death is during the first few years of a plant’s time in a new location and almost all of the time the loss results from imperfect site, soil, or care – especially watering.

What’s a plant owner to do? While I might wish that every tree sale included a watering lesson (with a test), I know it’s not going to happen. Maybe we could have an alarm system somewhere underground that beeps when the little root hairs first start to shrivel. They’re out of sight, so out of mind. I suggest some kind of marker system for new plants, to indicate “Recently Planted; Water Here.” Because I travel and sometimes need help with indoor or outdoor plants, I place a chopstick tied with pink tape to remind my husband or other helper which plants need attention.

Best watering practices

Watering rules are just our best guesses at what a particular plant needs since conditions are different in every setting, for every plant. But here are some principles to help:

• Set priorities for water use and where you spend the time. Recently planted woody plants come first, then stressed older trees, then perennials (which mostly show you when they’re drought stressed). In the big picture, your seasonal plants – veggies or annuals – may not be as important as the long-term investments.

• Water deeply, not daily. Check to see how deep the water reached and do one tree or one area right – before moving on with the hose.

• Choose your delivery method. Overhead sprinklers are least effective since half the water (or more) evaporates or misses the plants. Underground systems are effective only if they are placed and timed correctly – often not the case. The best watering is hand delivery with a wand to the base of the plant, or in the case of trees to the root area under the drip line (where most roots are).

• If you have a choice, water early in the day because less evaporates (compared to high noon) and the plants can dry out above ground. (Slugs and fungi love damp gardens that were watered in the evening.)

• Mulch can help keep moisture in the soil, especially if the soil was damp before the mulch went down. Make sure your watering gets through the mulch.

• If you see wilting, water immediately. It’s a sign of stress.

We can all hope for the right amount of rain at the right time in all seasons, but be smart about watering. For a plant it means life or death.

Sally Cunningham is a garden writer, lecturer and consultant.