Institute of Food and Agricultural Sciences
Hendry County Horticulture News
Beware of Poisonous Plants
Many home owners and gardeners are not aware that some of the common ornamental plants planted in and around our homes and gardens are highly poisonous. Some are toxic if eaten, other plants may cause irritation or dermatitis if they come in contact with the skin. It is a mistake to think that just because plants are occur naturally, they can't be very poisonous. While it is true that the effects of some plants are relatively mild and easily treated, some of the most toxic poisons known to man occur naturally in plants and can be fatal if as little as a seed or leaf is consumed. Ordinarily, no adult would think of eating the ornamental plants in their yard, but sometimes they are ingested accidentally or swallowed thoughtlessly by children. Touching or handling other plants may result in skin irritation similar to poison ivy, especially for sensitive individuals.
Most poisonous ornamental plants have such an unpleasant taste or consistency that it is unlikely that anyone would chew them very long or swallow any part of them. Some of them do not taste bad and it is conceivable that they may be sampled inadvertently. While this may be true for adults, the situation is quite different for children. Small children and toddlers often chew on any thing that comes to hand. Even babies in play pens may reach out and grab anything within reach. Lawn grasses and most lawn weeds are harmless, but play pens should be placed in an area that is clear of potentially dangerous plants. As soon as possible, children should be taught not to put anything except food in their mouths.
Dermatitis caused by contact with plants may be difficult to trace due to the time elapsed between contact and the onset of irritation. Not everyone is equally susceptible to contact dermatitis from exposure to poisonous ornamental plants. Just as with poison ivy, some individuals may experience a powerful reaction, while others are able to handle the same plant with little or no effect.
Some of the poisonous plants commonly found around the home have been highlighted below. This list is by no means complete.
Yellow allamanda is native of Brazil has become very common in south Florida. The plant grows as a vigorous vine or a weak shrub. The leaves are produced in pairs or clusters of 3 or 4. Large yellow flowers are produced in clusters near the ends of the branches. Individual flowers have 5 rounded petals attached to a cup like tubular throat. The fruit are rounded, spiny pods. In Florida, the plant, especially the fruit, has acquired the reputation of being dangerously poisonous.
Castor bean is a robust annual growing to the size of a small tree. The sturdy stems are erect and green to red or purple in color. The large green or reddish leaves are borne alternately and are star shaped with 5 to 9 lobes. The inconspicuous flowers are produced in clusters. The fruits are oval, green or red and covered with stiff spines. The seeds are black, white, or mottled with gray, black, brown or white and resemble beans. Castor bean is common around dwellings and disturbed ground around Hendry County. The seeds are quite toxic. The poisonous principle, ricin has reportedly been tested as a clandestine poison in cold war undercover operations.
Rosary pea is a woody vine growing to 10 -20 feet high. It is often found around older home sites. The delicate vine bears finely divided compound leaves, consisting of 8 -15 pairs of leaflets. The small pea shaped flowers are white to purplish in color. The seed pods are brown and resemble miniature bean pods. The seed are small, about 1/4 inch and are bright red in color, with a distinctive jet black mark covering about one third of the seed. The seed is particularly attractive to children due to the bright red color and prominent marking. This seed is extremely toxic. One seed may be sufficient to cause fatalities in adults.
Oleander is a common flowering ornamental shrub that is widely utilized as a hedges, screens, and ornamentals. Allowed to grow naturally it produces a large number of stems and forms a dense clump. The leathery leaves are narrow, elongated and pointed at both ends. Leaves are arranged in whorls of two to three around the stem. Oleander flowers are produced in clusters on the upper part of the shrub nearly year round. Flowers may be white, pink, yellow, rose, or red. All parts of the plants are poisonous. One leaf is sufficient to kill an adult. A number of individuals have suffered from serious poisoning after using the long straight branches to roast hot-dogs or marshmallows at barbecues. Inhaling smoke from burning oleander leaves or branches has caused poisoning.
A number of other common plants including: angel's trumpet, crown of thorns, diffenbachia, gloriosa lily, mango, poinsettia and pokeweed (to name a few) are also known to have poisonous effects. For more information, contact the Hendry County Extension Office.
In cases where poisoning or irritation due to plants is suspect, a doctor should be consulted immediately. A sample of the plant should be obtained for identification if necessary. While there have been tragedies around Florida, in most instances, a doctor will treat the trouble symptomatically and the incident will end happily. Good luck and good gardening and please don't eat the daisies.
Gene McAvoy is the horticulture agent with the Hendry County Extension Service. Direct your horticulture questions to PO Box 68, LaBelle, FL 33975, e-mail - firstname.lastname@example.org or phone 863-674-4092 or 863-983-1598. You are also welcome to visit the Hendry County Extension Office at 225 Pratt Blvd., LaBelle. Office hours are from 8:00 - 5:00.
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