 |
|
|
|
Photograph by Shari Kaplan
Olive trees are long-lived, picturesque trees that grow well in adverse conditions. The fruit can make a mess, however, so non-fruiting varieties are often sold.
|
Toxic plants are a concern in the garden and the wild
By TONY TOMEO
The weekend before last, during a trip to a beach near Davenport, my companion and I 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--which they mistook for Queen Anne's Lace--as other members of their group started a campfire. When I inquired as to their intentions, they told me that they planned to roast marshmallows on the sticks! 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 are not concerned with other species that 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. Potatoes are not actually fruit, however, but stolons--swollen subterranean stems. The other fruit listed are more commonly known as vegetables. One should not eat the leaves of any members of the nightshade family.
Toxic species in the family Solanaceae include foxglove, angel's trumpet, night-blooming jasmine and morning glory. In fact, foxglove, Digitalis purpurea, is the source of the potent drug known by the same name and used for heart disorders. Consumption of any of these species, as well as a few others of the family, may be deadly.
For those allergic to them, species of Primula and Grevillea may cause allergic reactions of the skin similar to those caused by poison oak. Because this is not commonly known, some garden enthusiasts experience the symptoms without knowing what caused them. Rhododendron, azalea and buxus (boxwood) may be toxic if ingested. Diefenbachia species are not 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 plant 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 not to consume anything that is not obviously an edible fruit or vegetable.
It seems that I have again utilized all the available space without concluding the discussion of street trees from last week. I hope to continue next week.
Tree of the Week: Olive
This is one tree that is too messy to be considered a suitable street tree. The olive tree, Olea europaea, is grown for its picturesque form and tolerance to adverse conditions--and sometimes, for its fruit. Most people, however, consider the fruit to be a nuisance and a potential health hazard for young dogs, who may binge until they become ill. Consequently, some fruitless or "semi-fruitless" cultivars have been developed.
Trees can grow rapidly when young, but slow down near maturity. They can eventually reach 30 feet tall and wide, on single or multiple gnarled trunks. The foliage is silvery gray. Although good soil is preferred, almost any soil is tolerable with the exception of poorly drained soil. Established olive trees require no supplemental irrigation but are more densely foliated with it.
Horticulturist Tony Tomeo can be contacted at 408.358.2574 or online at LGHORTICULTURE@aol.com.
|
|
|
|
Cupertino, California Since 1947
