Poppies are tall plants with showy, decorative flowers in the Papaver genus, along with several related genera, and they can be found growing on almost every continent on Earth. The most famous variety of poppy is probably Papaver somniferum, the opium poppy. The striking flowers of other poppy species are used in many gardens to add splashes of rich color, although the blooming period is short, and the plants can look somewhat weedy after the flowers have faded away.

As a general rule, poppies grow one to a stem, and the stems can get quite lengthy, standing well up above the green branchy leaves. The flowers have four petals, which often appear crumpled, and when the petals drop away, the poppies form drooping seedpods. The pods, stems, and leaves will exude a milky white substance called latex if they are cut; in the case of opium poppies, the latex from the seed pods is the raw material for opium. Other poppies do not appear to possess narcotic properties, although many are mildly toxic.

Opium poppies have been cultivated across Asia for centuries, and the substance was widely adopted in Europe once it was discovered. Opium and its derivatives, in addition to being mind altering substances, are also highly useful for pain relief. Most modern hospitals use synthetic opiates, rather than derivatives of the opium poppy, however.

Among the decorative poppies, two popular varieties are Iceland poppies, native to Iceland and Northern Europe, and Oriental poppies. Iceland poppies are in the Papaver genus, and look remarkably similar to opium poppies, although their varied colors include orange and white in addition to classic red. Oriental poppies also resemble opium poppies, with rich red petals which have dark purple to black bases.

There are three other genera which are classified as poppies: Meconopsis, Matilija, and Eschscholzia. California residents are familiar with Eschscholzia, which is the genus the California Poppy is found in. A number of other poppy species are classified in this genus, and they tend to perform well in Mediterranean climates, though they do not tolerate frost well.

As long as the soil drains well, Eschscholzia species thrive in poor soil and dry weather. Matilija is a genus unique to Latin America, with only two species, both of which take the form of small shrubs. These poppies also do well in poor conditions, and have large white flowers. Meconopsis includes poppies which grow low to the ground and die after flowering and seeding, such as Himalayan and Welsh poppies.