Opuntia's are a huge family with a species ranging from Canada's north to south America. They come in many shapes and sizes ranging from small ground cover species to in the colder areas of there range to tree species in their central range of Mexico and Central America. All species flower in the spring and this period can be prolonged. Individual flowers are short lived but large trees or clumps can have hundred of flower that open over a period of time.
All Opuntia are edible and have a long culinary history in Mexico and other Central American and South American countries. The most well known is Opuntia ficus indicus which is widely grown in Mexico.
Opuntia are very prolific plants and can be easily propagated by cutting and seeds. They also readily hybridize with each other to create many cultivars and hybrids. This has led to them becoming invasive in other parts of the world. Opuntia have escaped into the wilds of Africa and Australia where they have readily colonized the dry and desert like landscape. They have been so successful in these areas that they will likely never be eradicated from these lands.