Most of southcentral Pennsylvania has thirsted its way through a hot, dry back end of summer 2025, resulting in plants and lawns that are unusually parched for this time of year.
While this week’s showers will help, we’re not off the hook yet.
For one thing, not all areas got enough rain from the spotty showers to rehydrate the ground down into the root zones where plants really need the moisture. Damp mulch doesn’t help a drought-stressed tree or shrub.
For another, the showers have been more of a temporary rescue from brewing lawn and garden trouble than a signal that it’s time to put away the hose for the year.
This soil moisture could disappear pretty quickly if we get back into a dry pattern for the upcoming last four to six weeks of the frost-free growing season.
So what should you be doing? Is it time to worry? Where should you focus the hose and sprinklers from here on out if you can’t soak everything?
A sensible place to start is with your most-valuable stressed plants — things like that $300 new tree that the landscapers just installed in May or that sentimental rose bush that came from Grandma’s yard.
A good question to ask is, “Which losses would hurt the most if I don’t water and the plant dies?”
Keep in mind that any new or recently transplanted plant is more at risk of drought injury and death than existing, established ones.
Even drought-tough species aren’t very drought-tough until their roots occupy enough ground space to mine the survival moisture they need.
Most perennials and ornamental grasses develop reasonably good roots after two years in the ground, but trees, shrubs, and evergreens can take three to four years to adequately root-establish.
The upshot is that a 10-year-old dogwood can withstand weeks without water while the exact same variety in the same spot might need a foot-deep soaking twice a week if it was just planted this spring or last fall.
Ditto for lawns.
Turfgrass that’s two or more years old generally can go a month without water even in its dormant, summer-brown stage, while new grass (less than a year old) will die much sooner due to its limited root system.
That means an established lawn can go to the bottom of the triage list, especially since lawn irrigation requires a lot of water to keep green. However, replacing a whole lawn is expensive and labor-intensive, so a new one might rate high priority if your existing one has been brown and dormant for more than a month.
Most of this lawn has gone completely brown and would benefit from a light watering to make sure the roots don’t die.George Weigel
Ohio State University turfgrass science professor Dr. David Gardner says the way to tell the difference between dormant and dead grass is its color.
“Tan equals dormant,” he says. “Gray means dead.”
Note that you don’t need to deep-soak a dormant lawn. Giving it just a quarter-inch of water once or twice a week (or as Gardner recommends, a half-inch of water every two or three weeks) is typically enough to keep the roots alive without triggering new water-hungry growth. Of course, that’s assuming the roots haven’t already died.
Even established lawns don’t need the bigger quantities of water that deeper-rooted trees and shrubs use. Since grass roots are mostly in the upper six inches of the soil, lawns benefit from lesser amounts but more often, i.e. a one-inch watering weekly, or better yet, a half-inch watering every three or four days if your goal is to keep it green and growing. (Lawn-watering amounts can be measured by running a sprinkler with a rain gauge, empty tuna can, or similar container set in the irrigation area.)
Another low-on-the-list possibility involves annual flowers, container plantings, and vegetables.
These annual impatiens are wilting from lack of water, but if they die, at least they would have died from frost later in fall.George Weigel
Most of these are going to die come frost at the end of the season anyway.
If you can live with the likelihood that your petunias and cucumbers might croak in late September instead of late October, then those are candidates to go off hose-fed life support.
Conserve water by using kitchen-sink water to pour into the flower pots and over wilting annual-flower beds.
Most plants give you warning signs when they’re running into water trouble.
Wilting that doesn’t fix itself in the cooler, darker conditions overnight is one of the first signs. That’s a clue that the wilting is due to lack of water and not just high daytime heat.
The leaves of these astilbes are curling upward — a sign that the plant is under water stress.George Weigel
A second dry-soil indicator is when plants begin to lose their vibrant color and turn a dull or even yellowish shade.
Leaves that curl upward are another 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.
More serious is when existing foliage starts to brown around the tips and margins. That’s a sign that damage is already taking place.
The next stage of trouble is when plants begin dropping foliage altogether 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. There’s a good chance they’ll push new growth next spring.
When evergreens turn completely brown like this, they’re already dead. Watering won’t help.George Weigel
However, for needled evergreens, by the time needles are brown and dropping, the plant is already dead. Needles are good at holding enough moisture to stay green even when the roots have died days or weeks ago. Think about how a cut Christmas tree stays green inside throughout December even after it was completely decapitated in November.
When in doubt, a deep soaking every two weeks should head off the threat to evergreens when dry spells have dragged on for more than a month. The more recent the evergreen planting, the more likely it’ll need a water boost.
The last-gasp stage of dry-soil trouble is when plant roots and whole branches start to die.
You can tell for sure if the branches are dead by bending them (they’ll snap quickly if dead) or by scraping back a little bark (seeing green is a hopeful sign, brown wood is bad).
Beyond that fork in the road, the next destination is a kaput plant. At that point, you can deliver all the water you want, and it won’t matter.
Your soil and your plants’ particular location and genetic drought-fighting abilities also play a role.
Soil that’s heavy in clay turns hard and tends to crack when it dries.George Weigel
Heavily compacted clay soil discourages good root growth, which works against the plant when conditions turn dry. Try digging poor-quality soil in a hot, dry spell, and you’ll find it’s only slightly more friable than a concrete sidewalk.
Plants in full-sun locations and along heat-radiating asphalt surfaces also are more at risk.
Salty runoff from snow- and ice-melters used in winter is another factor that reduces a plant’s drought tolerance.
And plants that are native to damp habitats go downhill much faster than plants adapted to hot, dry climates, i.e. desert-climate succulents and salvias and Mediterranean natives such as lavender, catmint, and artemisia.
If it helps in the meantime, 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 at need.
Then keep tabs on how much rainfall we get from here on out. Don’t put the hose away too soon if October stays dry. Most plants’ winter-survivability goes down if they head into winter bone-dry, especially recently planted ones.
Use your finger or a water meter to gauge if the soil is damp or not and how deep the moisture is.
Remember, a “happy” plant prefers soil that’s consistently damp all around and to just below the roots.
A good, soaking rain of at least an inch per week is the best way to deliver that medicine.
But when nature doesn’t cooperate, the next best gift is a gardener bearing hoses.
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