Guerilla gardening 5

The road-block planters at the end of my street, which I inexpertly planted up 2½ years ago with plants I needed to move out of my garden pre-builders, have been looking bedraggled and waste-strewn (cans, bottles, snack-packets and cigarette ends) for ages. This afternoon some of the residents, mostly children, got together to remove the old plants, add compost and new plants and to replant some of the bulbs. My contribution was ground-cover strawberry plants.

A question for you gardeners: I haven't yet, but should I add Spanish bluebells and/or convolvulus (bindweed)? I'm digging marauding convolvulus out of my garden at the moment but its flowers are pretty and in a contained space might it be OK?  Or would it just strangle everything else?

Edit: after the first four comments all my convolvulus roots and bluebell bulbs are in the Council garden-waste bin!