Determining Your Tree’s Watering Needs
We’ve had a wet April, which means your trees are getting plenty of water! But the transition from spring to summer can be a tricky time to determine when to water your tree. Come this time of year, we recommend watering once a week when the weekly rainfall is less than one inch. But you might find yourself wondering, “when did it rain last?” (You can check here!)
Too much watering is the most common mistake, but consistent watering is crucial to getting these young trees established. A good way to know if your tree needs water is to check the soil. Stick a garden trowel or even a pencil 2-3 inches into the soil. If the soil at that depth is dry to the touch, then your tree is ready to be watered.
Once the dry season settles in, watering once a week is a good schedule (pick a day to water and keep it up!). Deep watering is best for these newly planted trees. Give 10-15 gallons at a time. Water slowly so that moisture soaks deeply into the soil and water doesn’t run away from the root zone. Mulching is a great way to hold water in the soil for your new trees.
Either a gator bag, hose on a gentle trickle for maybe 20 minutes, or a 5-gallon bucket with three 1/8″ holes drilled on the side at the bottom and filled 2-3 times consecutively works great. It’s a good practice to move the bucket around the tree each time you fill it to ensure that the whole root system gets water. Think of it this way: we’re trying to simulate a rain storm, during which all parts of the root system will get water at about the same time and rate.
It’s important to note that dry and hot are two different things. In late spring and early summer, we may get some seemingly perfect weather, and you don’t think to water your tree because it isn’t hot outside. But regardless of temperature, a dry spell is characterized as 2-3 weeks without significant rainfall. It might not be hot out, but your tree still needs a drink!
If the temperature gets over 90 degrees, bump your watering schedule up to twice a week. If we see another heat “event” coming, a good, deep soak beforehand can help the tree survive.
Spring has Sprung – What that means for your trees
Trees are breaking dormancy, but that doesn’t look the same for every species. Some are early risers, and some sleep in. A bunch of factors go into it, including species, daylight, and temperature. Here are some things you can do to take care of your trees this time of year.
It’s a great time to refresh mulch as needed. The objective is to mulch the tips of the roots as they grow outward from the base of the trunk. They will grow into soil that’s moderate in temperature and contains moisture, factors that mulch will provide. Because the roots are growing outward, when you mulch trees in their second year in the ground, aim for more of a 4-5′ diameter ring of mulch, still 3” thick, about a foot from the base of the trunk.
You may have noticed that some trees hold their leaves through winter. They’re called marcescent leaves, and they are a sign of last season’s growth. You’ll see them on native oaks like Oregon white oak (Quercus garryana) and scarlet oaks (Quercus coccinea). Come spring time’s flush, these leaves will be shed to make room for new growth. You can use these leaves as mulch!
Go easy on the pruning
It’s best to go easy with regard to pruning during “bud break.” This is when sap is rising up the tree, after having dropped to the roots in the fall. As the sap is rising, some trees (maples, for example) will “bleed” if pruned as sap is rising. It’s not harmful to the tree—that’s where maple syrup comes from, after all—but it can be disconcerting to see.
It’s almost time to start weekly watering for newly planted trees. “Deep and infrequent” is the recipe for success. Starting mid-April, 15 gallons all at once, once a week is ideal. Either a gator bag, hose on a gentle trickle for maybe 20 minutes, or a 5-gallon bucket with three 1/8″ holes drilled on the side at the bottom and filled 2-3 times consecutively works great.
If the temperature gets over 90 degrees, bump that up to twice a week. If we see another heat “event” coming, a good, deep soak beforehand is very wise as preventative medicine.
By Brighton West
Trees need water. That’s why Friends of Trees staff and volunteers tell every new tree owner to give new trees 10 to 20 gallons per week during the dry season. We’re glad to see lots of ooze tubes and five-gallon tree-watering buckets around Portland.
But did you ever wonder why trees need so much water?
First, let’s look at photosynthesis. Water + Carbon Dioxide = Plant Material + Oxygen. You probably knew that already. Plants need water to make oxygen.
But there’s more—a lot more. It turns out that only ten percent of the water that’s sucked up by a plant’s roots is used for photosynthesis. The rest is used for transpiration.
Through transpiration, water evaporates from the undersides of leaves and is drawn up from the roots. This process cools the leaves, exchanges oxygen and carbon dioxide, and moves nutrients up the tree.
No water in the soil = no cooling of the leaves = no nutrient transfer and no photosynthesis.
So water those trees when it’s dry outside. And if you want a more detailed explanation of transpiration, complete with words like stomata, xylem, and lysimeter, check out Wikipedia.
–West is Program Director for Friends of Trees.
By Kate Farrington
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.
What costs $20, rhymes with ‘snooze,’ and lets homeowners sleepwalk through their summer time tree watering duties?
The Friends of Trees Ooze Tube, on sale now, is simple to install and relies on possibly even simpler technology that guarantees adequate tree watering for up to three weeks.
Friends of Trees plants several thousand new trees in Portland every year and even has a corps of Summer Inspectors who check on the health of young trees. The reality is that neglect happens, and in the dry summers it can lead to death for a tree.
If watering at least twice a week is not an option during the summer, homeowners should consider a drip irrigation system like the Ooze Tube for their watering needs.
Basically, each Ooze Tube comes with two special emitters that force water to travel through an elongated maze, ensuring that a very slow, continual drip absorbs into the tree’s surrounding soil.
Watch below for instructions on how to install, and call 503-282-8846 to order your Ooze Tube today!