Got a Sick Plant? Bring it to the Doctor: By RON SULLIVAN

Special to the Planet
Tuesday September 07, 2004

The dozen or so petitioners at Saturday morning’s Sick Plant Clinic at the UC Berkeley Botanical Garden brought offerings ranging from dried leaves to big branches: a sheaf of photographs, a pear, a Japanese maple twig, an orchid growing on a bark slab. 

They all had the same questions: What’s wrong with my plant? What can I do about it?  

The implied third question—What did I do wrong?—could give the session a confessional air, but what happens is much jollier. 

Dr. Robert Raabe, UC plant pathologist, and Dr. Nick Mills, UC entomologist, convene a cordial team at the conference center of garden the first Saturday of every month to diagnose plant illnesses and recommend remedies, at no charge, to anyone who walks in with a request and enough information to figure things out. 

The easiest way to ensure that is to take a piece of the poor plant along—in a securely sealed container, please; a zipperlock bag is ideal.  

Last Saturday, Raabe and Mills were joined by plant pathologist and arborist Ann Northrup, Master Gardener Ermadene Tilley, and Liz Waterman of the California Rare Fruit Growers to answer questions and consult. A couple of microscopes were handy, to get a better look at insects and infestations and signs of disease. 

Raabe offered to take one leaf sample home and try to culture whatever was attacking it: to grow out the hidden organism until it showed its identity. He also explained how that works. One of his plant pathology students was attending, and he took the opportunity to educate her and the rest of the crowd on things like the distinction between a sign and a symptom. 

The room quickly filled with chatter, a detectives’ cascade of questions, answers, guesses, refined answers, explanations, and advice. People swapped stories. People showed off interesting flowers as well as what Raabe has been known to call “beautiful examples” of fungus spots or insect damage. People peered through microscopes and flinched. Impromptu, focused anatomy and natural history lessons were given. These folks clearly just like explaining things, and they’re good at it.  

One client wondered aloud if her mystery insect was trying to make lace when it attacked her shrub. Another allowed his caterpillars to pose for photos. The atmosphere was more one of excited discovery and puzzle-solving than sickroom gloom, in spite of the occasional bad news about verticillium wilt. There was, in spite of much opportunity, absolutely no scolding.  

If this were about human medicine, I’d call it “holistic.” Most of the advice given was not about what pesticide to apply but about how to keep the plants happy, because a healthy plant is less susceptible to disease and more able to fight one off. If a sick plant is dosed but the conditions that made it susceptible aren’t changed, chances are it will just get sick again.  

Quite a few examples of plant damage were culture problems, rather than pests or disease: brown-edged leaves were evidence of sunscald or thirst, and sometimes that in turn was caused by soil-mix problems. Plants from Mediterranean climates, unaccustomed to summer water, were dying of fungus infections at the root or crown. (Answer: Plant them in fall and let the winter rains establish them.)  

To keep plants healthy, it helps to know them. Know what they are, where they come from, what conditions they prefer, what they’ll tolerate and how to help them endure unaccustomed conditions. Put them in places where they’ll thrive—sun, shade, clay, gravel. Learn how to plant, water, and fertilize right. If you don’t know, ask! Garden people, whether they’re yard owners, nursery workers, or just mavens, generally like to talk about gardens and plants. Keeping your neighborhood’s ecosystem healthy helps a lot in the long run. An overfertilized monoculture with all the natural predators starved or killed out is an invitation to disease.  

Sometimes plants just get sick anyway. That’s when to consult the Sick Plant Clinic. It happens every month, 9 a.m. to noon, first Saturday, at the UC Botanical Garden, 200 Centennial Drive, in the canyon above the stadium. Admission is free (and you can sneak a look at the garden afterwards) but parking in the lot across the road is fifty cents an hour, payable in advance at a machine on the lot. Make an estimate of how long you’ll stay and then double it because the place is too much fun to leave.  

The garden is throwing a plant sale on-site on Sunday, Sept. 26, 10 a.m. to 2 p.m. Dr. Raabe will be among the experts giving advice there. He’ll have an educational display with plant samples and disease examples, where you can take the first steps toward solving your own problems.