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How to keep your trees happy after hail and drought

Huge sycamore trees line the jogging path at McKinley Park in East Sacramento. These trees took a beating during April hailstorms.
Huge sycamore trees line the jogging path at McKinley Park in East Sacramento. These trees took a beating during April hailstorms. Sacramento Bee

Drought or no drought, this year has been tough on trees.

Dry months in January and February gave them little extra moisture to survive when irrigation systems are usually turned off. March and April storms pummeled fragile new growth and strained limbs already weakened.by years of stress.

Then, it hailed -- more than once. Those icy nuggets inflicted countless tiny wounds on plants, especially trees.

On April 16, hail in the greater Sacramento area ripped through fresh spring foliage on sycamores and other shade trees that had already leaved out.

"The big sycamores can take it," said arborist Matt Morgan, assistant district manager of The Davey Tree Expert Company’s Sacramento office. "Hail mostly effects smaller or younger trees. It damages so many leaves, the trees can't create the sugars they need to stay healthy."

In addition, the hail can damage bark, creating entry points for harmful pests and bacteria on twigs, limbs and trunks.

"Japanese maples, dogwoods; trees with thin barks suffer the most," Morgan said. "Their bark is so thin, hail can cause scarring and cankers can form. Those injure the tree's health."

Although April storms pushed Sacramento over 80 percent of normal precipitation, trees are still coping with after-effects of California's epic five-year drought and a very soggy 2017. The recent dry-wet winter-spring pattern didn't help.

"We're starting to see effects of this past winter," Morgan said. "There's a lot of dead stuff on trees. It seemed like there was enough water, but it was sporadic. January and February, there wasn't any rain, then they finally got a good soaking in March and April. It was actually better this way than the other way round (with wet months in early winter) because the trees had moisture in spring when they were growing rapidly."

That late April rain caused outbreaks of anthracnose, a fungal disease that attacks foliage and twigs, Morgan noted.

"That's the major issue right now," he said. "Because of that late rain, anthracnose is causing leaves to drop. Sycamores and ash are the biggest offenders. We're seeing a lot of leaves on the ground -- and it shouldn't be happening right now."

This fungus overwinters on dead limbs or leaves. Proper pruning and clean-up around the tree usually keeps it in check.

The good news: Triple-digit heat -- which will be here soon enough -- can practically wipe out this fungus. If given proper care, effected trees will sprout new leaves. and return to health.

Trees take awhile to adjust to change, and many have had to cope with dramatic shifts in their surroundings.

"During the drought, people changed their landscapes," Morgan noted. "They took out their lawns and went to drought-tolerant plants. That impacted their trees, too."

The push for more water-efficient landscapes continues. Local water agencies are pairing their water-saving messages with pleas to help trees.

"Water efficiency is important, no matter the weather," said Amy Talbot of the Regional Water Authority, which represents about two dozen local agencies. "This year, we're really focusing on trees. We're partnering with the Sacramento Tree Foundation to get this message across: The importance of watering trees properly."

"Trees play such a major role (in Sacramento) -- especially when it's hottest," said Torin Dunnavant, SacTree's director of education and engagement. "We need their shade. But they're going to need help (this summer), especially during high heat."

Sacramento's urban forest is dependent on its caregivers, he noted. It's not just about tree health; besides providing shade, city trees also help clean the air, mitigate heat islands and improve overall public health.

"Trees need people," he said. "And we need trees. We want everybody to recognize that they need to help to keep Sacramento healthy by taking care of their trees."

So many tree health issues stem from the roots and improper irrigation. Shallow watering -- the kind usually associated with lawn sprinklers -- leads to weak, shallow roots.

"Trees need deep, infrequent soakings," Morgan said. "It's so hard to say the actual amount of time you should water your trees; it depends on so many factors. But deep watering is not 5, 10, 15 minutes of weekly sprinklers. It takes more time."

Ideally, soaker hoses spiraled around the tree or in a circle 6 to 8 feet away from the trunk can deliver that slow, deep irrigation.

"You need that water to get down to the roots," he said. "It should penetrate at least 6 inches. The easiest way to check is with a long screwdriver. If you can push it into the ground easily without pressure, then the water is getting down to the roots."

Maintaining that moisture can be a challenge during blistering Sacramento summers. That's where mulch can become a tree saver.

To help mulch Sacramento's urban forest, local water agencies will host "Mulch Mayhem" on three Saturdays in May. These free events will supply local residents with chipped wood mulch; one cubic yard per customer. (Come prepared with a shovel and a way to carry it home.)

Why mulch? It slows evaporation, moderates soil temperature and even controls weeds. As it breaks down, mulch also adds nutrients to the soil, further helping trees. (When mulching trees, make sure the mulch does not mound around the trunk or it may cause rot.)

Mulch saves money, too. According to the Sacramento Tree Foundation, residents can save 30 gallons of water for every 1,000 square feet of landscaping by adding two to three inches of wood chips, shredded leaves or other organic mulch around plants and four to six inches deep around trees.

Said Dunnavant, "You can save water and your trees."

Mulch mayhem

Get free mulch at these locations on these Saturdays:

  • When: 9 a.m.-noon May 5
  • Where: Carmichael Water District, 7837 Fair Oaks Blvd., Carmichael
  • Details: 916-483-2452, carmichaelwd.org
  • When: 8 a.m.-noon May 5
  • Where: Sierra College, Overflow Lot, corner of Rocklin Road and El Don Drive, Rocklin
  • Details: 530-823-4850, pcwa.net
  • When: 8 a.m.-noon May 12
  • Where: Sacramento Marina, 2 Broadway (close to Miller Park), Sacramento
  • Details: 916-808-5605, SacWaterWise.com
  • When: 9 a.m.-noon, May 12
  • Where: San Juan Water District, 9935 Auburn Folsom Road, Granite Bay
  • Details: 916-791-0115, sjwd.org
  • When: 9 a.m.-noon, May 19
  • Where: Parking lot at 9000 Foothills Blvd., Roseville
  • Details: 916-774-5761, roseville.ca.us/mulchmayhem

Mulch mayhem

Get free mulch at these locations on these Saturdays:

  • When: 9 a.m.-noon May 5
  • Where: Carmichael Water District, 7837 Fair Oaks Blvd., Carmichael
  • Details: 916-483-2452, carmichaelwd.org
  • When: 8 a.m.-noon May 5
  • Where: Sierra College, Overflow Lot, corner of Rocklin Road and El Don Drive, Rocklin
  • Details: 530-823-4850, pcwa.net
  • When: 8 a.m.-noon May 12
  • Where: Sacramento Marina, 2 Broadway (close to Miller Park), Sacramento
  • Details: 916-808-5605, SacWaterWise.com
  • When: 9 a.m.-noon, May 12
  • Where: San Juan Water District, 9935 Auburn Folsom Road, Granite Bay
  • Details: 916-791-0115, sjwd.org
  • When: 9 a.m.-noon, May 19
  • Where: Parking lot at 9000 Foothills Blvd., Roseville
  • Details: 916-774-5761, roseville.ca.us/mulchmayhem
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