Problem with native holly

I planted two native holly trees last year and one has died. The leaves turned a dark purple underneath and then on the top, hey are also leathery. The second is now turning purple underneath and there are also some leaves that seem to have lost that firm feel that holly usually has. They feel soft like any normal tree even where the spikes are. They are planted with other trees and shrubs in a corner that was quite wet but has dried out due to the planting of trees that like wet conditions.