I would like to take out three very large oleanders and put in fruit and nut trees. Is it OK to plant edibles where oleanders have been?

– Lynn McClain, Carmichael

According to UC Master Gardener Bill Pierce, all parts of the oleander plant are toxic.

But oleanders are only poisonous when any of their parts are eaten. Ingestion causes nausea, vomiting, dizziness and irregular cardiac action.

Smoke from burning the wood can also be toxic.

But it's safe to plant food plants in soil previously occupied by oleanders. Be sure to enrich the soil before setting out your new plants, as the oleanders will have used many of the nutrients.

We have a well-established, 15-year-old wisteria planted between our neighbor's fence and driveway at our home in east Sacramento. This wisteria has flourished for many years and there is a wisteria of similar age (taken from the same plant) across the driveway only a few feet away that is doing quite well.

Last spring, we noticed the green leaves on the plant drying up – even with all of the rain we had. We watered it, cut down new shooters, and nothing improved. Now all the leaves are a pale yellow and the plant looks dead.

Do you have any ideas about what may have happened?

– Jim and Michelle McFetridge, Sacramento

A visual inspection of the plant and growing conditions is needed before providing a diagnosis, said UC Master Gardener Bill Pierce.

From your description, it would appear that your plant has a vascular problem caused by one of the root rot pathogens. However, the University of California's "Diseases of Landscape Trees and Shrubs" doesn't indicate that wisterias are prone to this.

Nevertheless, our long wet spring and a poorly drained site could have caused this to happen.

The other possibility is that the plant has a canker disease. Fungi-causing canker organisms can enter the plant through injury or stress.

If your plant has a canker disease, there should be soft spots on the canes that ooze sticky sap. There is no cure for canker diseases.

How does one get rid of ivy and climbing fig "footprints"; you know, the part of the plant that still clings tenaciously to the wall after one has pulled the main plant off of the wall? I have tried several chemicals, even meat tenderizer, to no avail. It seems like sandpaper works the best but that scrapes the finish off the building.

– Scott Whitten, Carmichael

Those "footprints" are left by vine tendrils, where the plant anchored itself to the wall. According to UC Master Gardener Bill Pierce, there was no information about removing vine tendrils from buildings in the Master Gardener library.

When you look at cleaning or etching masonry, TSP (trisodium phosphate) or muriatic acid is recommended. Muriatic acid is corrosive and can be harmful to your health; use care with this product.

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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