White and pink Lily of the valley are one of my favorite flowers and happy memories of childhood. There perfume fantastic. I love to pick a bunch for a table decoration. They grow in any type of soil from sandy to clay if planted only 1/8" deep and love dappled shade.
I like the way they travel around the garden. Old shoots do not re flower they send new shoots out each year.
Bigred18 look for Lily of the Valley in someone's garden and ask for a root. They can also be propagated by seed flowering in the 2nd year.
As for being poisonous to dogs most plants and bulbs are, so we wouldn't have gardens or take dogs into woods if they are not trained or on a lead and frightened of them being poisoned!
All lily, Oleander, rhubarb leaves, Hydrangea, Daffodils, Bluebells, Amaryllis, Ivy, apple seeds, Cyclamen, yew etc. can cause problems if eaten by dogs. As can chocolate! Check out www.dogstrust.org.uk/poisonous plants.