4. BULB-BEARING PLANTS OF HOUSE AND GARDEN
TOXICITY RATING: Moderate. Incidents of poisoning by these plants
is rare, but special care must be taken, especially with lily
of the valley.
ANIMALS AFFECTED: Pets are primarily at risk, cattle have been
poisoned by iris.
DANGEROUS PARTS OF PLANTS: Bulbs, rootstocks, whole plants.
CLASS OF SIGNS: Stomach upset, vomiting, diarrhea. For lily
of the valley, additional signs may include irregular heartbeat,
convulsions, and death.
PLANT DESCRIPTIONS:
1. Convallaria majalis (lily-of-the-valley, lily family).
A familiar low-growing garden perennial, forms dense clumps from
slender rootstocks called "pips.'' The lily-like leaves are
parallel-veined (fig. 4A), and from them rise flower stalks that
bear small white blossoms all on one side. The flowers are bell-like
and fragrant and rarely develop into the red to orange-red berries.
2. Hippeastrum vittata (amaryllis, amaryllid family).
A houseplant (fig. 4B) that blooms in only a few weeks after forcing
in the wintertime. At first one or two 1 to 3 feet tall, naked
stalks appear, each bearing from one to four large, six-petaled,
red, blue, white, or bicolored flowers. Later several sword-shaped,
fleshy leaves develop from the base of the plant.
3. Hyacinthus spp. (hyacinth, lily family). These potted
or garden plants grow from a 1 to 2 inch diameter bulb (fig. 4C).
The 8 to 12 inch long leaves are narrow, somewhat trough-shaped,
and fleshy. The small fragrant, white, pink, or blue lily-like
flowers are borne on a leafless stalk that is taller than the
leaves.
4. Iris spp. (iris or blue flag, iris family). These commonly grown garden perennials also occur wild in wet
meadows, marshes, roadsides, lakeshores, and stream banks. Branching,
fleshy rootstocks bear clusters of long, sword-like leaves in
which the base of each leaf is folded over the base of the next
higher leaf (fig. 4D). The flowers, blue with a yellow heart in
our wild species but purple, blue, yellow, or reddish-brown in
cultivated varieties, have three upright "standard"
petals and three pendant "fall" petals. The fruit is
a dry capsule.
5. Narcissus spp. (daffodil, jonquil, narcissus; amaryllid
family). Springtime in Indiana is officially proclaimed by the
yellow trumpets of daffodils (fig. 4E). These perennials produce
lily-like leaves and slender stalks that each bear a conspicuous
orange, white, or yellow flower with six petals, parts of which
fuse to form the trumpet.
SIGNS: This group of plants is divided into two sections. The
first section includes lily of the valley, and the second section
includes the other bulbs.
Lily of the valley is the far more dangerous plant, producing
a mixture of many cardiac glycosides, especially convallatoxin.
Toxic signs in pets after they chew on the plant would include
stomach upset, vomiting, irregular heartbeat, convulsions, and
death if sufficient quantities are consumed. The toxin in lily
of the valley acts in a similar manner to the toxin in foxglove,
a plant from which digitalis, a powerful cardiac medication, is
derived.
The bulbs or corms of tulip, daffodil, jonquil, narcissus, amaryllis,
and iris produce primarily gastrointestinal signs (vomiting and
diarrhea) after consumption, and are not as toxic as lily of the
valley. Pets are more likely to come into contact with these
plants than are horses or livestock, however, livestock (cattle)
have been poisoned when grazing wild-growing iris and eating the
rootstocks.
Concerning pets, dogs are the most likely to consume the bulbs,
and the usual time for poisoning is when the bulbs are removed
from the ground or stored prior to planting. This is not a common
poisoning, but some animals, once they find the stored bulbs,
will consume them. While unlikely, some animals will dig the
bulbs up in the yard and eat them. The toxic components in these
bulbs is not well identified, but may be a mixture of alkaloids,
having an irritant action on the gastrointestinal tract.
FIRST AID: For lily of the valley, contact a veterinarian immediately.
If the animal is vomiting, allow it to continue to do so, since
this will remove the toxin from the gastrointestinal tract. If
the vomiting is severe or persists, a veterinarian needs to be
contacted. In cases where the pet has eaten a large quantity,
emergency treatment is imperative. For the other bulbs and for
iris, vomiting and diarrhea should resolve in a few hours. If
the signs continue, or if the pet is weak, sick, pregnant, nursing
,or old, a veterinarian can provide supportive care until the
toxin is eliminated.
SAFETY IN PREPARED FEEDS: It is unlikely that these plants would
be incorporated into animal feeds. On the rare event that this
occurs, the toxins would remain, and the feed is then unsafe for
consumption.
PREVENTION: Do not allow livestock to graze where iris grows,
especially if there is insufficient forage available. For pets,
do not allow access to stored bulbs, and restrict access to bulb
beds and newly planted bulbs. Never pen or place an animal within
reach of these plants, especially lily of the valley, since the
pets (including birds) may nibble them out of boredom.