After a cold, wet spring, many of us look forward to a summer spent in our gardens. Soon I'll have dirt under my nails and that particular delight that every gardener has when digging in the soil and watching things grow.

It wasn't until I was a veterinary student that I learned that many of those wonderful plants in my yard actually contained toxins that could harm my pets or children. Plants rarely come with warning labels, or are the staff at nurseries always knowledgeable about this aspect.

Plants and animals have been in a love/hate relationship as long as they have coexisted on this planet. Being immobile, plants benefit from having animals carry their seeds and pollen to distant locations, so they developed ways to attract animals through flowers and fruits. But it doesn't benefit plants to be completely destroyed by animals, so many of them also developed weapons, chemical weapons that confuse, sicken and even kill animals. In the glorious diversity that is the natural world, there are an amazing variety of chemicals plants can produce.

Sometimes the chemicals, in low quantities, are actually valuable medicines. An example is foxglove, which is a beautiful flower planted in many gardens. It is also the original source of the cardiac medicine, digitalis. In higher doses, that chemical becomes a cardiac toxin. There is a very fine line between the safe and toxic level and this varies in each plant.

Some other beautiful, common plants that contain toxins are oleander, azalea, rhododendron, Japanese yew, even the lily of the valley. So, with poisonous plants all around us, why are we so unaware of them and the risk they pose to our animals? One reason is that our pet species, by and large, are not plant eaters. Another reason is that many of these toxic plants are very bitter and unpalatable. Even herbivores rarely touch them if other feed is adequate. You should never feed the clippings of ornamental plants to herbivores like your child's pet rabbit or the neighbor's horse (people sometimes do this thinking they are giving a treat to the pony down the road). And for those of you living in rural areas, where there are livestock or wildlife, you need to consider not only the poisonous potential of ornamentals you might plant, but the native plants that could be in your pastures as well.

Plants also vary in the toxicity of their chemical arsenal. Some plants are PG-rated and you would have to ingest a lot to cause problems. Some are X-rated and only a little bit of plant material can be harmful. I have found what I consider X-rated plants at my local garden stores.

If you have a garden full of rhododendrons, I am not saying that you should take a chain saw to them. Here are some common sense things you can do: Familiarize yourself with the names of poisonous plants, through books and Web sites (some listed below), before you go to the garden store and ask questions while you are there. Depending on your circumstances, you might choose to not plant some of them. In addition, familiarizing yourself with plants around your property that contain toxins can save valuable time in the rare event that a poisoning does occur. If you have a puppy (or toddler) who is "chewing everything in sight" including plants in your yard, then providing it with appropriate chew toys and limiting its access to the garden would be safer for the puppy and plants both. When ornamental plants are trimmed, throw away the trimmings. Unless you know for certain they are non-toxic, don't put them in your compost, leave them where a bored pet might chew on them, or use them for any other purpose. And lastly, write up a list of the plants in your garden that your animals have access to. If your pet were to become suddenly ill with signs of possible poisoning, your veterinarian could use this list to rule in or out a plant toxin as the possible cause.

Have a joyful and safe gardening season.

www.aspca.org/site/PageServer?pagename=apcc
www.ansci.cornell.edu/plants/
www.vth.colostate.edu/poisonous_plants
http://cal.vet.upenn.edu/poison/