Got a spot in the garden or landscape that's giving you fits, but you haven't been able to figure out what's wrong?

Sometimes, the best tactic is to take a plant sample or a photograph to someone who may be able to identify and solve the problem. Help often can be found at a county extension program office (in Dallas County, call 214-904-3053), or from our House & Garden e-mail newsletter, which is sent each Friday morning and has questions from readers and replies by me. Or take a plant sample to a certified professional at a garden center.

Regardless of whom you contact, be a careful observer and provide as much of the following information as you can.

Identify the plant. Some insects and diseases are attracted to certain plant species. Knowing the plant species narrows the field of possible causes.

If possible, provide the approximate age of the plant. Like gardeners, plants can have age-related problems.

Describe the symptoms. In the case of leaf spots, note their size, shape and color and the changes that occur as the leaves grow. Leaf spots caused by fungi differ from those caused by bacteria.

When did the symptoms appear? Problems require varying periods of time before damage becomes apparent. Spots that appear overnight could indicate one problem, while those that appear over a period of several days could indicate something else.

Where on the plant did you first observe the symptoms? Was the entire plant affected or only a few twigs or branches? Did symptoms appear first on the lower leaves or the upper, newer leaves? Yellowing on lower, older, leaves indicates different causes than the same symptoms on upper leaves.

Are only plants of one species affected, or are the same symptoms apparent on other types of plants? Some problems are species-specific. Compare plants of the same species that are growing in different parts of the yard and compare the soil and drainage in those areas with symptoms that are apparent on the plants.

If you document yard or garden conditions, you will get better answers to your questions and probably will have a more beautiful and manageable landscape.

H.S. Stevens is a lifelong gardener and former vegetable specialist with Texas Cooperative Extension. For more advice from him, see the Q&A in the House & Garden free weekly online newsletter on DallasNews.com.

E-mail house&garden@dallasnews.com