Hot Fun in the Summertime
The great thing about native plant gardens – or so I’ve been told and sincerely hope – is they can withstand the slings and arrows of weather extremes. Such as the sauna that is August in the DC area. A well-established landscape of local species growing in conditions that suit them should require little-to-no irrigation, fertilizers, soil amendments, herbicides or pesticides.
New plantings and really unusual weather situations do require attention. So if you've got some fledgling vegetation or Pacific Northwest-style heat records on your hands, what should you be doing around now? Here’s what some of the experts say:
Give your new plants plenty of water. It can take 12 months or more for roots to get established in a new home, so supplemental watering during that first year can be critical — assuming you’re not under water restrictions. A good rule of thumb is your garden should get a deep soaking, whether from rain or your hose, twice a week. Possibly thrice-weekly in a drought. The top five to six inches of soil should get moist. This leads to deeper and thus more self-sufficient root systems over time than if you water a little bit every day.
Water strategically. It’s best to water in the early morning, which cuts down on evaporation, reducing waste and increasing the chances those hopefully deep-growing roots will benefit. Also, aim water at the base of plants rather than broadcasting it. Sprinklers, for example, spread water every which way, including into the atmosphere, and while they’re busy being profligate they get leaves wet, which can cause fungal diseases. I’m guilty of using a sprinkler to tackle large beds; gotta rethink that. The pros say soaker hoses are a better way to get water where it’s needed without the downsides. If you have just a few plants or containers, a well-aimed watering can or regular hose should be fine.
But avoid over-watering. Water is too precious to waste – even in the name of saving a few plants. Also, too much H2O suffocates roots and causes them to rot. So it’s a good idea to check the soil moisture before you turn on the spigot. Stick your finger down into the soil several inches. If it feels cool and moist, you’re probably okay. If it feels dry and dusty, that’s your sign to add water. You may also want to invest in a soil moisture meter. I recently got one made by Xlux (don’t ask me to pronounce that) for about $13 on Amazon.
Check your plants daily. Learn to read their quirky personalities. Some plants – I’m looking at you, hydrangeas – are divas that wilt at a hint of sunshine, but then spring back into shape overnight or when they get a shady reprieve. Those theatrics can probably be ignored. If you’re seeing droopy leaves that persist through shade or into the morning, though, or if leaves are turning crispy, it’s a good bet more water is needed. To make things confusing, wilting can also be a sign of over-watering, but in this case you’ll also usually see yellowing or browning leaves. Another point to keep in mind that the same plants placed in different locations may have varying needs. One at the top of a slope may get less moisture than its sibling at the bottom, for example. Using my handy Xlux meter (“clucks”? “zlucks”? “ex-lux”?), I was surprised at the wide variation in moisture levels within the same bed, depending on elevation, tree cover, and probably other factors I don’t yet understand. The point is, keep an eye on those distinctive trends, habits and needs, and adjust accordingly.
Avoid pruning and transplanting. Save these tasks for cooler days when your plants are better able to tolerate the short-term stresses involved.
Protect soil from excessive evaporation and heating. The best way to do this is with dense plantings of complementary native species that together shade the soil. If that scenario is still aspirational for you, now’s not a great time to add new plants (put that on your list for fall). But you can add a two-inch layer of mulch now, being careful to leave a three-inch gap around trunks and crowns.
Make a vacation plan. Yes, you should make a plan to get yourself on a vacation. You’ve earned it! But you should also make a plan for those new native plants or drought-stressed gardens to get some care while you’re gone. Maybe hire the kid next door to do some periodic watering. Or trade garden-sitting favors with a green-thumbed neighbor. Alternatively, you could set up a drip or soaker hose on a timer. I haven’t done the soaker/timer thing myself but am looking into it.
Triage if you must. If you don’t have sufficient time or water to take care of every complaining plant during a drought or heat wave, focus on a) the ones that were most recently seeded or transplanted and b) those that would be most difficult or expensive to replace.
Remember, by autumn the irrigation pressure should abate. And by next summer your new native plants will have put down bodacious root systems, making them far more self-sufficient. Think of the extra time you'll have to coddle your next generation of natives.
Bees' Knees will be taking a break for the next couple of weeks. Lemme know in the comments if there are topics you'd like to see covered when posts resume later this month. Meanwhile, have yourself some hot summertime fun, preferably in native wildlife habitats!
Master Gardener Manual, Penn State Extension
“Gardening in the Heat,” Lauren’s Garden Service website, July 21, 2016.
“Caring for your New or Restored Native Garden,” Edge of the Woods Native Plants website, March 13, 2018.