Rainbow is part of the Solenostemon genus and is a Coleus variety. Its scientific name is Solenostemon scutellarioides 'Rainbow'. A type of Ornamental, it mainly grows as an Annual plant - which means it typically only grows best for a single growing season. Rainbow is known for growing to a height of approximately 1.24 feet (that's 38.0 cm in metric).
Rainbow Coleus is great for inexperienced gardeners and those that like low maintainance gardens.
This variety plant info is provided by the myfolia gardener's wiki. All details about Rainbow have been kindly provided by our members.
By our calculations, you should look at sowing Rainbow about 56 days before your last frost date.