- Author: Ed Perry
Trees normally begin to show fall colors in late October, especially after a couple of cold nights. If you are seeing orange, yellow, red, burgundy, and purple leaves on deciduous trees this time of year, it's a symptom of stress. You might not be able to do anything to correct the problem now, but much can be done to prevent a repeat next fall.
First, determine the source of the stress and correct it. Look closely at the tree. Check for wounds on the trunk from mechanical injury or sunburn. If early fall color is the result of wounds, take steps to prevent further wounding. The trunks of young trees can be protected from string weeder damage with plastic sleeves. Better yet, place chip mulch on the soil around the tree to remove the temptation to mow or weed right up to the trunk.
Determine if the tree is growing in a site where the roots may be restricted by pavement or buildings. Is it possible the roots were recently cut? Root disease, recent disruption to roots from construction or grade changes, surface soil compaction from vehicles or foot traffic and girdling roots can also cause trees to develop early fall color. If surface compaction is a problem, loosen the soil by cultivating to a depth of 4 to 6 inches. This should improve moisture and oxygen penetration. Follow up by watering the tree deeply.
The best way to prevent stress and early fall color is to make sure the tree receives sufficient deep water during the summer. If you haven't already, deep water your tree. Sprinkler water does not provide adequate water for trees, so supplement with a hose, focusing the water underneath the tree canopy. For mature trees, water needs to penetrate to a depth of 12-18" to provide enough water.
For questions about your trees, contact the Master Gardeners at (209) 525-6862 or fill out this form http://ucanr.edu/ask/ucmgstanislaus
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
- Author: Kathy Thomas-Rico
It’s the day after Thanksgiving. Time to get ready for Christmas, right?
Perhaps we should soak up what remains of autumn before we embrace the wintry wonders of the holiday season. Get outside and look at all the fall color in our area. This year seems particularly colorful. The Chinese pistache (Pistacia chinensis) trees glow nearly fluorescent pink-orange, the liquidambars (L. styraciflua) are the pyramidal gold-orange-red standouts, the burgundy ‘Raywood’ ashes (Fraxinus oxycarpa) look positively velvety, and the Japanese maples (Acer palmatum) are the petite rubies and topazes of the landscape. Even the crape myrtles put on a good show, before the winds of November stripped most of them nearly bare.
If you’re in downtown Vacaville soon — perhaps for Merriment on Main on Tuesday, Nov. 29, when the community Christmas tree is lighted at 6 p.m. — you really ought to see what I think is the best example of fall beauty in all of Solano County. On the corner of Buck Avenue and West Street, in front of what is still called the old Hartley house, is an absolutely stunning Ginkgo biloba tree. I’m not sure of its age, but considering its size and how slow growing these trees are, it must be close to a century old. This tree literally stops traffic when it goes gold, which should be right about now.
Ginkgos, also known as maidenhair trees, are considered living fossils. In fact, fossils of the ginkgo’s distinctive fan-shaped leaves have been found that date back to 270 million years ago. The trees were long thought to be extinct in the wild, but are now native to two small areas in China.
If you’re interested in planting one — ginkgos do well in our zones — be aware of the sex of the tree you choose. According to the UC Integrated Pest Management website, “Male trees are better as female trees produce messy, smelly fruit. Trees prefer areas with full sun. Plant in loose, well-drained soil, and provide moderate to regular amounts of water. Established trees only need occasional water.” (Check for more information on the few problems ginkgos face: http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/maidenhair.html)
Of course, one thing leads to another with all this lovely color. The season is called “fall” for a reason.