This weekend during a trip to a beach near Davenport, we met a very friendly cairn and border terrier mix named Archie from Sunnyvale. After petting him, it occurred to me that he had likely been in contact with the thicket of poison oak surrounding the trail. Although dogs are not allergic to poison oak, I am!

We later observed other visitors to the beach collecting tall floral stems of poison hemlock as others of their group started a fire. When I inquired of their intentions, they told me that they planned to roast marshmallows on them! Of course I informed them of their error and I believe they ate their marshmallows raw.

Toxic plant species are not only a concern in the wild, but in the garden as well. Most garden enthusiasts are aware that oleander is mildly toxic, but not concerned with other species which are considerably more toxic.

Many of the species of the family Solanaceae are among the most toxic plant species commonly found in home gardens. Strangely, the family also includes non-toxic species that produce popular fruit; such as tomato, pepper, eggplant, tomatillo and potato.*

Toxic species in the family Solanaceae include foxglove, angels trumpet, night blooming jasmine and morning glory. In fact, foxglove is the source of the drug known by the same name used for heart disorders. Consumption of any of these species as well as a few others of the family may be deadly.

Another toxic species that is in the family Scrophulariaceae is Digitalis purpurea.

Species of Primula and Grevillea may cause allergic reactions of the skin similar to those caused by poison oak for those who are allergic to them. Because this is not commonly known, some garden enthusiasts experience the symptoms without knowing what caused them. Rhododendron, Azalea and Buxus may be toxic if ingested. Diefenbachia species are not actually toxic directly, but produce sap that crystallizes in saliva, lining the throat with a very sharp, rigid, glass-like substance.

Unfortunately, there are far too many toxic species for me to list in this column. Although the majority of the most popular landscape species are harmless, concerned garden enthusiasts should investigate potential hazards associated with any questionable species. To be safe, children should be instructed to not consume anything that is not obviously an edible fruit or vegetable.

It seems I have again utilized all the available space without concluding the discussion of street trees from last week. I hope to continue next week.