May I point out that willow roots can do a lot of damage to drains and foundations and shouldn't be planted anywhere near a house? It's never happened to me because I wouldn't plant a willow in a small garden but it happened to my brother in law and wife. They had to have drains replaced of a house they had bought because roots had broken drains.ย
Posts
Gardening in Central Norfolkย on improved gritty moraine over chalk ... free-draining.