In Northamptonshire the plant [dwarf elder] is known also as Dane-weed, and Defoe in his 'Tour through Great Britain' speaks of his going a little out of the road from Daventry to see a great camp called Barrow Hill, and adds :—
"They say this was a Danish camp, and everything hereabout is attributed to the Danes, because of the neighbouring Daventry, which they suppose to be built by them. The road hereabouts, too, being overgrown with Dane-weed, they fancy it sprang from the blood of Danes slain in battle; and that, if upon a certain day in the year you cut it, it bleeds."—Vol. ii. p. 362.
Can this really be the second largest hillfort in the country? It's a bit of a cheat - 4.5 acres inside a bigger 150 acre enclosure. It used to be covered with BBC masts but Daventry council own it now and there's only one left. Apparently it's a bit of a birding site and full of butterflies in the sun. A late bronze age axe has been found there.