Keeping Plants Alive in Hot, Dry Weather

This is the second draft of my column on watering. I tossed out the first one a few days after writing it. I could tell the minute it was finished that something was wrong, so I didn’t turn it in right away. I’m glad I did that because after lugging the hose around for another spell of hot, dry days, I realized what the problem was—my advice was a bunch of bull! Why? I think my attempt to offer up normal-world suggestions about watering during the summer of 2018 which, to me, has felt like a non-stop onslaught of diseases, bugs, rain, heat, wind, heat, humidity, heat, dryness, heat, dryness and more dryness, is about as helpful as my applying a Band-Aid to a torn-off arm stump.

As a trained Master Gardener and longtime horticulture writer, I am used to answering questions and offering suggestions based on time-tested research. I’m usually fine with that, except when the research seems questionable because it feels like someone who has never gardened in their life came up with the results. Or, the study was funded by Bayer/Monsanto or some other entity with a vested interest in saying something crappy is actually great and totally safe.

Perennials like golden rod help sustain pollinators later in the season.

But now there’s something new to chew on: We are living in uncharted, extraordinary times. As our planet warms, and we try to garden in increasingly unusual and erratic conditions, it seems only logical that the research we rely on needs to evolve to.  In some ways, I’d say we’re just winging it out there. So, while it’s a good idea for gardeners to be aware of the commonly advised watering know-how, I think we also need to rely on our common sense and do what we can for our gardens, the earth and our spirits. (Please don’t email to say natives will solve all of these problems. They won’t.)

Here is some of the main oft-heard, research-based watering advice:

• Water in the early morning or evening when temperatures are cooler to reduce evaporation.
• In general, lawns and established perennials, trees and shrubs need about 1 – 2 inches of water per week, including rainfall.
• Don’t use sprinklers because overhead watering can lead to diseases that favor wet leaves.
• Don’t spritz things with the hose because those little sips of water don’t encourage plants to establish strong root systems they can depend on.
• Water established lawns, trees, shrubs and perennials only about once per week to give soil time to dry out in between waterings. This will motivate plants to develop stronger, deeper root system that the plants can rely on in dry times.
• Water newly planted things frequently for the first two or three years as they establish root systems.

All of this advice is reasonably sound in many ways, and I believe the studies that  suggest watering plants deeply and infrequently, rather than letting them wilt and dry up, helps keep them healthy from year to year. But I’ve also long thought that this watering advice isn’t super practical for humans with busy lives and even moderately sized gardens. Recent weather has only heightened that disconnect. For example, we don’t have an in-ground drip system, so I have always used an overhead sprinkler as best I can, and that is rarely before breakfast or around happy hour. Even though I do water at least an inch per week, I have recently resorted to giving many plants a refreshing drink from the hose because I know it’s not good for them to be so stressed in these drought-like conditions.

Sprinklers are not an ideal way to water. But if that’s what you’ve got, go with it.

In the last month, in an effort to sustain our gardens according to the watering rules I have mostly always followed, I have run up our water bill while worrying that I am single-handedly emptying out the Mississippi and, still, many plants look half-dead and zombie-like. Normally I find watering relaxing and enjoyable, but now it feels more like making rounds in a hospital, so I have decided to go into triage mode.

Bees love ligularia, so I’ll keep watering it into the fall.

I’m letting go of the watering rules and focusing first on watering the trees and shrubs, which can easily succumb to stress and disease if they are not watered well. How much to water depends on the age and size of the tree. In general, newly planted trees need a couple of inches of water per week for the first couple of years. For older trees, before watering, measure the diameter of the trunk, place your hose anywhere inside the drip line (under the tree canopy) and let it run slowly (no gushing water) for one hour for every inch. Remember, most tree roots are in the two inches of soil. Ideally, you want to move the hose frequently when you water, so you wet the roots all around the base of the tree inside the dripline.

Also on the triage watering list are fall-blooming perennials that pollinators depend on, like ligularia, Japanese anemone, asters, toad lily, turtlehead, boltonia and golden rod. Annuals that require large amounts of water to look only moderately happy have been chucked into the compost bins. And perennials that are sad, brown and fried, like ginger, ferns, geraniums, lady’s mantle and a few other plants, have been cut to the ground for the season. I’ll cut down the rest as they brown too. I know it is way early to have done that, and I don’t know how it will affect their overall health over time. But continuing to water as I normally would feels too much like fighting Mother Nature, and that doesn’t seem right to me. I’m not sure how my gardens will fare in this changing world. All I know is, things are changing, and we’re going to have to change too.