When I say I want rain, I mean real rain. Not a passing shower or a tropical gullywasher, not some effete drizzle but constant, temperate rainfall lasting for several hours. I would be happy if it would rain thus and regularly from now until Thanksgiving, because the past two months have been not only stubbornly arid but hot as well, and moisture has been wicked out of the top layers of soil at a key moment in the year when our gardens need full hydration. (The National Weather Service announced a “flash drought” on Sept. 26, meaning the recent dryness has quickly overcome long-term record wetness. September is on track to be one of the hottest and driest on record.)
If you haven’t seen (or heard) the shrubs and trees screaming, you’ve been seriously distracted. The dogwood out back is curling up, the azaleas are in extremis, and the maple leaves are brown-tinged with environmental stress. The hydrangeas? We won’t even mention the hydrangeas. There is a reason the paths are lined with dry, fallen leaves. The trees need to get rid of these little water pumps to avoid getting sucked dry.
Ironically, the delayed effects of last year’s flood are causing some older trees, including beautiful white oaks, to die now. But back to the drought.
Any tree or shrub planted in the past two or three years should receive special attention — that is, watering — because the root system is still maturing. Young street trees, which live by definition in stressful conditions, need your help. On its website (caseytrees.org), Casey Trees offers video demonstrations on watering street trees.
In attending to all your parched plants, how you water makes all the difference. Squirting a shrub for 10 seconds before you move on to the next is of little value. What your plants need now is a deep soaking. And remember, the feeder roots of trees extend well outside the dripline. You can set up a sprinkler, but I would start with hand-watering. Professionals use a hose-connected watering wand made for plants; it delivers a lot of water but gently.
For treasured shrubs and ornamental trees, I recommend the Higgins Hydration Happaratus: two five-gallon buckets and a garden hose. Set the hose stream on a modest flow. While you apply the contents of one bucket to the root zone of each plant, the other bucket is filling.
In terms of priority, you should attend to trees and shrubs less than five years old, trees that heartily dislike drought — for example, dogwoods, river birches, winterberry hollies, sweetbay magnolias, black gums and willows — and “trees with limited soil volume,” such as street trees, said Mark Buscaino, the executive director of Casey Trees. Each needs 25 gallons of water a week, he says.
If you haven’t watered anything yet, I would spend some time just wetting the lawn, tree roots and plant beds, and return to those areas the next day. The topsoil needs to be moist and receptive before it can become fully charged, in the way you must first prime a bone-dry sponge to absorb water.
The object is to get the moisture down several inches, between four and eight, and that will take a while, depending on the nature of your soil. You can measure the depth with a long screwdriver; plunge it down until you can’t and take a reading.
The difficulty with an impulse sprinkler is that the pattern you set never stays put (in my experience), and what you don’t want is for the water to fall wastefully on pavement.
One problem with the dryness is that we are in the midst of cool-season grass seeding. Or not. This is the best and really only time of year when you can establish, renovate or patch a fescue lawn from seed; at our latitude, spring seedlings are quickly consumed by the cauldron of summer.
Renovation is often accompanied by dethatching — this opens the soil surface for successful seed germination — or by core aeration, which mitigates soil compaction and also aids seeding. Jon Traunfeld, the director of the Maryland Home and Garden Information Center, thinks such working of the soil is rendered almost impossible this year.
A silver lining: Your now-brown lawn may not be as bad as you think and should come back with rain. “If the lawn was otherwise green during the summer, I wouldn’t worry about it,” he said.
Any lawn seeded now would need watering daily until seedlings get established — not to mention a good soaking in advance of the work. If you have a large lawn with no capacity to water it and cannot prep the ground for seed-to-soil contact, overseeding would be a waste of money.
Last year’s rains made lawn renovation tough, if not impossible, Traunfeld notes. Maybe we should make 2020 the year of the lawn makeover. Or better yet, plan to reduce the size of the lawn and plant something more interesting than fescue grasses.
Even without a drought, woody plants and perennials should not be fertilized now; they need to harden up for winter. Lawns, too, should be spared fertilizer when stressed by dryness, even if they are fed during a normal fall.
This is also the time of year when buds on spring-flowering shrubs and trees and fruit trees are developing — another reason to give them a good soak.
Evergreens in particular need to have their thirst slaked before winter to minimize winter burn and freeze damage. Although there is still time to do this, the danger is that when the temperatures become consistently cooler, people will forget about soil dryness.
Autumn is the time to plant spring bulbs, but working the soil is near impossible when it is rock hard. If necessary, bulbs can be planted as late as December; perhaps the ground will have softened by then. In the meantime, they should be kept in a cool, dry and breezy location. If you have room, the fridge, not the freezer, is a good storage cabinet.
Another potential hazard lurks in the wings. Newly seeded lawns, plant containers and fall veggie beds will like a daily spritz, but watering ornamental plants every day will put them in waterlogged soil. In permanently wet soil, the roots will suffocate.
Once the garden is well soaked, leave it to dry out. Plants need an inch or two of water a week, and that’s it.
But do attend to the thirst, for reasons that now go beyond the obvious value of a beloved plant. A healthy tree takes carbon from the atmosphere. A dead one doesn’t.
Tip of the Week
Don’t rush to tidy the declining top growth of perennials. Seedheads provide food for birds, and the stalks take on their own architectural beauty in the weeks ahead. Ornamental grasses should be left to stand through most of the winter before getting their annual chop.
— Adrian Higgins
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