Q: I have a 30-foot redbud tree that has been losing its outer bark quite severely on the lower 4 feet of the trunk. Also, it's losing its leaves – way too early for fall. What is the cause (and cure) of this?
– Kay Edises, Folsom
A: According to UC master gardener Bill Pierce, there are a couple of probable causes. Redbuds (Ceris ssp.) are susceptible to verticillium wilt, a fungus that is always in the soil and becomes active under moist conditions. It causes leaves to yellow and drop early and often results in the death of the tree.
Trees with this problem often recover when given a small dose of nitrogen fertilizer and are put on a reduced irrigation schedule.
Root rot and crown rot is another disorder that affects these trees, particularly if they are planted in lawns. Good drainage is essential for redbuds. They grow on well-drained soils in the wild.
Lawn trees with this problem can recover if the soil is removed to a depth of 6 inches all around the trunk and out about 18 inches. This gives the crown of the tree – the point at which the roots and trunk meet – a chance to dry out and stop the rotting process. Crown and root rot symptoms include leaf drop.
Tree trunks also split because of sun damage, lightning strikes, freezing, too rapid growth and excessive irrigation.
Redbuds are not particularly sensitive to sun, although the long, hot afternoon sun in our area can damage trunks. If you think this may be the problem, paint the exposed trunk with a mixture of white latex paint diluted 50/50 with water. This will prevent future damage.
"My guess is that your tree has had excessive moisture," Pierce said.
Q: Am I crazy, or are there really more insects this year, especially now that the weather has warmed up? I can't ever remember seeing more spiders, gnats, ants or mosquitoes.
I'm even noticing cockroaches, which I've never in my life seen or had anywhere near my home. Something to do with the strange weather?
– Adam Struck, Sacramento
A: UC master gardener Bill Pierce's answer: Yes. Weather has a direct impact on insect populations.
Mild winters and lack of frost – to kill overwintering eggs – increase insect populations. In addition, a wet spring provides lots of moisture sources for mosquitoes.
Spiders are mostly beneficial because they feed on pest insects, which are plentiful.
Last summer had similar weather conditions and a big bug boom. Another wet spring and cool summer meant two buggy summers in a row.
Q: A few years ago, a plant appeared on the edge of my property. I didn't notice it until this year when a bloom appeared.
The bloom is large and shaped like an ice scoop. It is motley green on the underside and wine colored on the inside. Its stamen looks like a 10-inch long Japanese eggplant. And the aroma – it smells like decomp! What is it? I hope it isn't an illegal plant, cause I didn't plant it!
– L. Macfarlane, Gridley
A: Plants whose blooms smell as foul as this one should probably be illegal, said UC master gardener Bill Pierce. What the birds or the wind has brought you is Dracunculus vulgar, the dragon arum or voodoo lily. Isn't it interesting that the botanical name is similar to that of the famous vampire from Transylvania?
The plant is native to Europe. It grows and flowers in the spring and then disappears until the following year.
Another possibility for your mystery plant is Arum sintenisii; it looks similar but is not as large as the dragon arum. It also has a very foul scent.
GARDEN QUESTIONS?
Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties.
Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to h&g@sacbee.com. Please put "Garden Detective" in the subject field and include your postal address. To contact your UC Extension directly, call:
• Sacramento: (916) 875-6913; 9 a.m.-noon and 1-4 p.m. weekdays
• Amador: (209) 223-6838; 10 a.m.-noon Monday through Thursday; email ceamador.ucdavis.edu
• Butte: (530) 538-7201; 8 a.m.-noon and 1-5 p.m. weekdays
• El Dorado: (530) 621-5512; 9 a.m.-noon weekdays
• Placer: (530) 889-7388; 9 a.m.-noon on Tuesdays, Wednesday and Thursdays or leave a message and calls will be returned
• Nevada: (530) 273-0919; 9 a.m.-noon Tuesdays through Thursday or leave a message
• Shasta, Tehama, Trinity: (530) 225-4605
• Solano: (707) 784-1322; leave a message and calls will be returned
• Sutter, Yuba: (530) 822-7515; 9 a.m.-noon Mondays and Tuesdays and 1-4 p.m. Thursdays
• Yolo: (530) 666-8737; 9-11 a.m. Tuesdays and Fridays, or leave a message and calls will be returned
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