Utilising space wherever it may be, Tokyos few greenhouses are often found on rooftops. Here great collection of cacti and succulents can get the sunshine that gets past the tall skyscrapers. 

On our last Tokyo trip we where lucky enough to visit both Kakusen-en greenhouses, packed full of rare plants. 

Also located in Shirokane is a three story building and headquarters of Botanize and their rooftop greenhouse. Here you can find a wast collection of Pachypodium and also pick up a pot or two.