One of the world's most famous gardens, unpretentiously beautiful and quintessentially English, Sissinghurst rests deep in the Kentish countryside. The gardens, with their many different themed "rooms," were laid out in the 1930s around the remains of part of a moated Tudor castle by writer Vita Sackville-West (one of the Sackvilles of Knole, her childhood home) and her husband, diplomat Harold Nicolson. Their relationship was loving but complicated, as both had a string of extramarital same-sex affairs; Vita, famously, had a decade-long romance with Virginia Woolf.
Climb the tower for a wonderful overview of the gardens—as well as a peek inside Vita's study en route—then descend to see them up close. There's the stunning White Garden, filled with snow-color flowers and silver-gray foliage; the herb and cottage gardens, which showcase Sackville-West's encyclopedic knowledge of plants; the Delos Garden, which brings a slice of the Mediterranean to the heart of Kent; and other spaces. As well as the gardens, there are woodland and lake walks all around, making it easy to spend a half day or more here.
If you love it so much you want to stay, you can—the National Trust rents the three-bedroom Priest's House on the property for a minimum stay of three nights; prices start at around £1,000 and rise significantly higher in midsummer. See the National Trust website (but you'll need to book well ahead).
Sissinghurst Castle Garden is 16 miles east of Tunbridge Wells on the A262.