The gardens are open April to November only. May and June are the best months: the irises are in bloom, the wisteria hangs over the Japanese bridge, and the Clos Normand is at its most colourful. July and August bring the largest crowds — if you can visit in late April or early October you will find the garden still beautiful and far fewer people.
Summer weekends bring coachloads of day-trippers from Paris. Arriving when the gates open at 9:30am makes a significant difference. Weekday mornings in late spring are the ideal combination of weather, bloom, and quiet.