Trees need water. Especially in lengthy droughts like this one, you might want to think about giving your thirsty trees a long drink with soaker hoses — the ones that put out a measured drip over an extended period.
Arborist Casey Roland, a former Ashland Tree Commission member, adds that it’s equally vital, along with the water to “mulch them like crazy” to keep the moisture in. That can be done with such materials as hay, straw, leaves and cut grass.
Mulching also reduces the overuse of limited summer water supplies.
Trees may look like they’re just standing there contentedly, doing their thing, but Roland notes the Rogue Valley is practically desert country.
“Any tree is dealing with drought and stress in summer,” he says. “Last year we got 8 inches of rain and the year before, it was 21. The resulting stress signature from trees is picked up by pathogens and insects and they call all their friends in.”
Roland recommends to soak the ground in the outer half of the canopy and not next to the trunk. The roots are in the outer area and extend beyond the canopy area, so water out past the drip line (the edge of the canopy).
Watering can be done with a sprinkler, drip hose or by just letting an open hose run on it. Water deeply, not frequently and stop when runoff starts. A thorough watering every two to four weeks is enough. You are trying to wet the top 2 to 4 feet, where the roots thrive. Soils with clay, such as are found in the eastern side of the valley, absorb water more slowly.
You can test the depth of wetness with a soil probe, pushing it in the ground up to 16 inches. If the soil blows away from your probe, it’s obviously not wet, says Roland. Granitic soils, as found on the west side of the valley, absorb water quickly, so don’t overwater, as it can leach out nutrients. Mulching is important to retain moisture and also improves the quality of the soil.
Many bugs are killed by wildfires, but many are fleeing, too. Because they are looking for vulnerable trees, you don’t want to do any pruning in warm weather, as it gives them an entry door, he notes.
“Pine beetles rush to your pruning cut,” says Roland. “They are an easy mark. You want to whistle past that graveyard from June to August.”