Not many people know this -today marks the start of Belfast's Rose Festival.

Thousands of people will come to the celebrated city centre rose garden to marvel at 4500 blooms and stroll amongst new varieties. Maybe fewer than last year. Not for the first and, sadly, probably not for the last time Belfast’s many and varied civilised attractions have been pushed to the media margins by another bout of mindless sectarian violence.

It is, after all, the epicentre of the marching season; that open season for idiocy when a certain proportion of men and women cloak their internecine squabbles in a veneer of traditional “celebrations” and counter demonstrations. What is being celebrated is a battle which took place over 320 years ago; a 17th-century conflict which seems terminally lodged in the 17th-century mindset of those whose civic pride is still infested by civic but hardly civil prejudices.

Belfast is a city twinned with its other self. A vibrant European city with gleaming structures, boutique hotels, retail therapists, a fine festival and buzzing nightlife. And, at the same time, a sullen city still partially mired in its troubled past; a city whose “peace” walls bisect communities, even children’s playgrounds, creating the interface areas where trouble is no more than a stone’s throw away. A city which, with no apparent sense of irony, includes a tour of gable-end murals depicting its violent troubles as an official part of its tourist menu.

In the wake of the Good Friday peace accord, it seemed the bulk of the citizenry would sign up to the commercial and social dividend that promised. In the wake of that apparent watershed other UK taxpayers continued to throw money at the new world order in the province, including stumping up for its parliament and its members when the latter went into one of their lengthy, extended, and expensive huffs.

Gradually, painfully slowly, it seemed the city was becoming more comfortable in a 21st-century skin. Even the horror of a young Catholic policemen murdered in April by Catholic dissidents for the “crime” of joining the force, evoked a small crumb of comfort when his funeral mass brought cross-party attendance including the Protestant First Minister.

Then came the summer of 2011 where violence with no obvious trigger broke out again apparently instigated by loyalist youths. Armour-plated vehicles, riot police and young men intent on mayhem came back on to the streets.

The petrol bomb, weapon of choice for the urban cowboy, made an unwelcome re-appearance. Inevitably, sickeningly, the two tribes squared up again in tit-for-tat assaults on whatever target their logic-free reasoning deemed “the enemy”.

A few years ago Belfast put itself forward as one of 12 British candidates for the accolade of European City of Culture for 2008. As part of the judging panel, I spent some time in the city, entranced by the enthusiastic welcome, shocked by the sense of apartheid still so very evident. Somewhat bemused to be regaled by a Scottish country dance set, we were advised that the young girls in question didn’t do the Irish variety as that belonged to the other Ireland.

Fast forward to a couple of years ago and, in the finale of a European mediation conference, a local woman beside me at the closing concert talked me through which instruments belonged to which tradition. This is a city where even a joint orchestra can play to Catholic and Protestant codes.

The people who have worked so hard and so long to integrate this city now have to find a way to dismantle mental walls as high as any of the concrete variety. They can embrace a fascinating future for their city, new Titanic quarter and all, or they can let the hoodlums tear down a hard-won decade of progress.

This is not just a little local difficulty. There are idiots who sing and chant their sectarian hatred at Scottish football matches. Some Scots also drink from this poisoned well.