Butterfly Weed grows 2'-3' tall in my garden, and is easy to grow from seed.  As its name suggests, it attracts butterflies.  It's not the best butterfly-attracting plant, but some butterflies favor it.  Monarch butterfly caterpillars can sometimes be found feeding on the leaves.  Butterfly Weed begins blooming in mid-June, and can bloom into August if dead flower heads are removed.  I usually cut the stems back to just above a new bud.  Very few of the plants are well-budded.  In those cases, I cut the stems back to a good leaf joint and hope for an extended bloom.  There is a downside to growing Butterfly Weed.  It comes up much later than anything else in the garden, and drops its leaves early, leaving empty stems and a bare spot in the garden.  The empty stems have to be cut down to keep your garden looking tidy.  The stems are very fibrous and hard to cut with pruning shears.  I under-plant my Butterfly Weed plants with Sweet Alyssum (Lobularia maritima) to fill in the bare spots.  If allowed to set seed, Butterfly Weed may become just that - a weed.  Each seed has its own silken parachute to float to other parts of your garden, where it will reseed itself.  Butterfly Weed has a very long taproot, and is difficult to transplant or remove.