Roses are one of the most well-known flower families, with over 100 species and new hybrids being created daily. Although they grow in nearly every plant form, from shrubs to trees to vines, nearly every species within the Rosa genus has pinnately compound leaves that grow alternately. The only roses that do not have this type of leaf formation are a handful of evergreen species in southeast Asia.
What is a Pinnate Leaf?
Pinnate leaves exhibit a feather-like appearance--pinnate derives from the Latin word "pinna" which means "fin", "wing" or "feather". They have veins that grow out from a common axis, which appears symmetrical.
Other Important Characteristics
Rose leaves, in addition to being pinnate, also have a serrated margin. They range in size from 3 to 20 cm and sometimes have prickles on their underside.
How Rose Leaves Grow
Rose leaves generally grow in an alternate pattern. This means that the leaves grow in each direction, one at a time, from the stem. In terms of the botany, this means that the leaves have singular nodes, as opposed to leaves that share a node and grow in an opposite pattern. If a rose leaf is growing to the left, slightly above and below the spot where it's stemming will be leaves stemming to the right.