The university ordered dozens of Holestar lamp post baskets, window boxes and free-standing planters from Plantscape, all containing the tricolour scheme.
More than 10,000 planters, from hanging baskets to large multi-tiered floor-standing containers, were ordered, and the Ashbourne-based company started planting the 70,000 flowers to fill them back in April.
Plantscape also supplied two bespoke hexagonal planters which were stationed outside the centre in Runnymede, where the document was signed by King John on June 15, 1215.
Mark Stone, managing director of Plantscape, which is based in Ashbourne, said: "In the past few years we have supplied floral displays that have commemorated the Olympic Games, the Commonwealth Games and the centenary of the First World War, so it is wonderful to add the 800th anniversary of the Magna Carta to the list.
"Brunel University London is one of our most long-established customers and every year they take a sizeable number of planters from us. We are delighted that they have asked us to provide this patriotic display this year."