Tree Care

Summer Tree Care in the Pacific Northwest

Summer sun is here! If you got a tree from us this past season, you can expect a Summer Tree Inspector to come by to see how your newly planted tree is faring if they haven’t already. Longer, hotter summers mean that even species native to this region are struggling to stay hydrated.

“Unlike in other areas of the country, like the East and the Southeast… we don’t get any rain during most of a tree’s growing season. And so as far as tree care at this time of year, I’m mostly thinking about watering.”
–Litzy Venturi, Community Tree Care Coordinator

Each summer, we try to visit every single tree that was planted during the prior planting season. Our volunteer inspectors are trained to check on these young trees to make sure they’re getting the care they need to make it through their first summer.

Here are some pointers from our Summer Tree Inspector Program for protecting your trees in the heat. You can always visit our Young Tree Care Guide if you have any questions.

  • Water and mulch
    Trees depend on water to survive the heat. A protected environment that prevents evaporation is key, giving water an opportunity to go deep and be taken up by the roots. Here’s are some steps:
  • Create a mulch donut over the roots: Apply a three-inch layer of mulch over the root zone to prevent evaporation and help water reach a little deeper. Be sure to leave a three-inch gap of bare soil directly around the trunk; keeping the bark constantly wet creates an entry point for disease.
    • Mulch helps keep weeds and grass down, which limits the need for using lawn mowers and string trimmers near the tree’s trunk. Recommend hand pulling weeds/grass. Significant bark damage can impact its ability take up water, and can ultimately shorten a tree’s life.
  • Water when it is cool: Early morning or late evening is best. Watering during the heat of the day causes the water to evaporate before it can reach the tree’s roots.
  • Water deeply and cyclically, 15-20 gallons once per week:
    1) Watering bags: Zip a green Gator slow-release bag around the trunk (or place it next to it if it doesn’t fit) and fill it once or twice a week.
    2) DIY a 5-gallon bucket: Drill a 1/8-inch hole near the bottom of a plastic bucket, set it by the roots, and fill.
    3) A trickling hose: Set your garden hose to a gentle trickle right over the root zone for about 30 minutes.

As you water, you’ll start to get a dialogue going with your tree about how it handles the heat and you’ll notice how the soil is reacting too. Every tree is different. Here are some ways to observe and improve as you go:

  • Get a feel for soil moisture: You can push a pencil about two inches deep to see if the water is making its way into the ground near your tree’s roots. If it comes out clean, this is a sure sign your soil is too dry.
  • Trees can get overwatered, especially if a tree is being watered in addition to receiving water from daily lawn irrigation. While grass takes up a lot of the water, the soil around the tree’s roots, especially when it’s young, can end up with more water than the tree can take up with its limited roots. This can kill the tree
  • Widen the watering area: You can move your watering zone a few inches farther out from the trunk each summer. This encourages roots to grow away from the trunk, which assists with anchoring and better water absorption and nutrient uptake.
  • If you can’t water: If you go out of town or otherwise leave without watering for a while, your tree might look completely parched when you get back. Compensating with too much watering without letting soil breathe can lead to rot. It is better to give your tree one deep soaking to reset the soil and then return to a regular weekly watering.
  • Build up the soil: You can put down a layer of mulch every year to replenish the donut. As it breaks down over time it feeds the tree and creates well aerated soil. Also, a wide mulch ring can help lawnmowers and weed-whackers to keep a safe distance.

“Over the course of decades, if everybody mulched their yards, we could change the city’s soil structure to be much more amenable to microorganisms and plant roots.”
–Litzy Venturi, Community Tree Care Coordinator

Look Out for heatwaves
Keep an eye on the forecast and act before the heat hits. While temperatures above 85°F are stressful for trees, you should start taking precautions as soon as the forecast nears 80°F. Also, trees in direct sun or near concrete and asphalt are especially vulnerable, as those spots get much hotter than the official forecast.

  • Pre-water: Soak the ground two days before a heatwave arrives. This gives moisture time to sink deep into the soil.
  • Remove competition: Surrounding lawn grass and plants will compete for every drop of water. Keep the tree’s root zone weeded, and you can put friendly companion plants just outside the tree’s canopy.
  • Increase water during heatwaves: Water 10 gallons per inch of trunk diameter, three times weekly during heatwaves.
  • Pay special attention to vulnerable trees: Trees with thick, waxy leaves (like white oaks or tupelos) naturally handle heat better. Trees with delicate leaves (like vine maples) will scorch much easier. Make sure these trees don’t get missed, and get extra watering.

More resources

When looking for accurate tree care information, you can check out Western-specific resources that account for dry summer climates like ours:

Eugene

Summer Snack Time

 

The Eugene Team Talks Fruit and Nut Trees

It’s summer, which means trees are in their pure growing season. They’re soaking up the sun’s energy and using it to grow, and many are developing fruits and nuts. Trees are amazing for so many reasons, and one of them is that they grow food for us to eat, which is pretty magical when you think about it.

“It’s super important for people to be able to grow food for themselves,” says Eugene Director Erik Burke. “Sometimes people can see fruit trees as messy, but I think we can shift that thinking.”

Erik was recently visiting a street with a row of Lavalle hawthorns, which produce bright red berries. A man approached him and told him how much he loves to harvest the berries from those trees.

“He was giddy about the berries,” Erik says. “It was so awesome.”

Erik points out that in addition to the fruit trees you’d expect like cherry and apple trees, trees like oaks and hawthorns provide food to both people and wildlife. Fruits and nuts are one of the ways that trees can reproduce, and they rely on the cooperation of the ecosystem to make it happen. The tree provides a tasty snack and the animal spreads the genetic material within. Humans have been looking to trees for sustenance for millennia.

The Eugene-Springfield team hopes in the future to offer more fruit and nut trees for people to plant at their homes. Figs in particular are a climate resilient tree that don’t need watering after they’re established. Persimmons are a great option because they don’t drop their fruit during yellow jacket season. Chestnut and walnut trees are planted as bareroots, making them an affordable and sustainable option to get from local nurseries.

We recommend checking out our friends at Portland Fruit Tree Project for more resources on how to properly care for a fruit or nut tree and make the most of your new orchardist hobby. Growing food—on fruit trees in particular—comes with extra challenges, but it also comes with awesome rewards.

 

Tree Care

Leaflet: Aphids

Aphids are everywhere, but don’t worry!

We’ve been getting a few inquiries about aphids this summer. And with the arrival of the emerald ash borer (a devastating issue we’ll keep you posted on), we have plenty of reasons to keep an eye out for pests. In the case of aphids, however, we don’t need to fret about them on our trees like we do in our veggie gardens.

In almost all instances, you don’t need to take any action—the tree can take care of itself. Aphids will only make a noticeable impact if the tree is still working to establish itself, or is somehow otherwise weakened. We often see them on Oregon ash, like the one pictured. If some wilting or crinkled leaves have you worried, here are some action steps you can take. Some folks might want to go straight to spraying, but pesticides really aren’t necessary to deal with aphids.

If you have more than just a few aphids on your leaves, the first thing to try is to just rinse them off with water. A good hose down will take care of a minor infestation. If that doesn’t quite do the trick, you can spray with soapy water. A treatment like this just once or twice a year will be enough.

If you see any ladybugs alongside the aphids, that’s great! Ladybugs will eat the aphids, and their larvae will really go to town feasting on them.

Aphids are everywhere—there are even tiny ones floating in the air we breathe. Some trees, like littleleaf linden, will have so many aphids that you may feel a mist of aphid “honeydew” when you walk underneath. You guessed it, that’s aphid poop. Just think of it as a nice reminder that trees are part of a larger ecosystem of living things.

Tree Care

Leaflet: Summer Glory

Shop now, plant later

Now is when trees are in their full glory. You can see it, smell it, and feel it whenever you walk around the neighborhood. It’s not a good time to plant trees—we’ll wait until our planting season, October-April—but now is the time to be thinking about what tree you might want to plant. Look for the species on a Friends of Trees tag. Consider how big a tree gets when it’s mature.

“When we call you later this year to see what tree you want, you won’t be able to look around and see what a tree looks like in the middle of summer,” says Neighborhood Trees Senior Specialist Andrew Land. “Summer is an outstanding time to look around.”

Beyond finding a tree whose glory really speaks to you, now is also a great time to think critically about the conditions where a particular tree can succeed. A core aspect of the Friends of Trees ethos is right tree, right place. We want every tree to survive and thrive.

If you see a tree you really like and think, maybe I want one of those, observe the place that it’s in. Consider the conditions: sunlight, moisture, competition, space. Compare those to the conditions in your own yard where you might want a tree.

When we talk about a tree getting full sun, we’re really only talking about the growing season from mid-April through September. The sun exposure in your yard changes considerably from season to season. Now is the time to study how much sun your new tree would get next summer.

“Thinking ahead is how we set up a tree and its steward—you—for success,” Andrew says.

We always invite you to connect with staff about tree selection. And we encourage you to keep an open mind to something new and different. Don’t be afraid of big trees. Consider trees that will be more resilient to climate change. Glory is subjective, and there are so many factors beyond appearance.

“Take the Hardy Rubber Tree, for example,” Andrew says. “It’s nondescript. You wouldn’t necessarily call it pretty. But it’s the best air filter of all the trees.”

Or take the Amur Maackia. It’s not known for its spring flower or its fall color, but it casts a beautiful dappled shade and does really well in the urban environment. When it comes down to it, survivability is the biggest priority.

“Think of all the benefits that a tree provides to people and community,” Andrew says. “Those benefits expand exponentially every year that a tree survives, which is why we want every tree to last as long as possible.”

Neighborhood Trees, Plant It Portland

Everything you could want to know about the ooze tube

By Kate Farrington

How an ooze tube should be
How an ooze tube should look (FOT file)

So, what is an ooze tube? It is a nifty little drip irrigation bag you can purchase for $20 from Friends of Trees to help water your trees in the summer months! If you have trouble remembering to water your tree, or you are a landlord and don’t get to visit your tree very often, the ooze tube allows you to only water every two to three weeks, instead of once a week.

And ooze tubes are super easy to install! Check out our video, which walks you through how to install your very own ooze tube.

Have an ooze tube but are concerned about that cut in the top of the bag? You are not alone. But there’s actually nothing to worry about! This cut is the opening that allows you to fill the bag with a hose. Above is a picture of what it should look like. If your bag is actually damaged, please let us know and we’d be happy to replace it.

If you would like to purchase an ooze tube, just drop by the Friends of Trees office at 3117 NE Martin Luther King Jr Blvd, Portland, between 9:00 am and 5:00 pm. Someone in the Neighborhood Trees program will be happy to help you purchase your ooze tubes.

–Farrington is a Neighborhood Trees Specialist with Friends of Trees.