On the deck, so you want it in a container, right? I have no experience with this, but regarding hardiness, I planted three kinds of shrubs this year and late last -- honeyberry/haskap (Lonicera caerulea) from a local farm that specializes in hardy perennials, and from the local soil and water conservation district, I got some service/june/saskatoonberry (Amelanchier alnifolia) and some Viburnum trilobum. Their leaflet with a variety of ornamental and native shrubs (and trees) is here: https://scontent-a-sea.xx.fbcdn.net/hphotos-xaf1/t31.0-8/1796752_708750435844505_1611309120_o.jpg

For a more ornamental, smaller shrub, I see beautiful Dwarf Flowering Almonds in many places (Prunus tenella), so there clearly is a variety hardy to zone 2. (I also see it listed as Prunus glandulosa or trileba, so I'm unclear about the species and varieties available.)

Here is a link that might be useful: