The Horikiri Shobuen is a small but very nice iris garden near my apartment in Katsushika Ward. It gets jam-packed in early June when the irises are in bloom, but is quite beautiful and nearly empty the rest of the year.
When I visited last Sunday, all the plants were covered in straw, ready for the winter. The idea is that the straw will attract bugs because it’s warmer, keeping them away from the plant itself. I’m not sure if it’s any more true than the popular pet-bottle theory of keeping cats away from your house or not, but it’s very attractive.
This straw-rope carousel is called a yukitsuri. It’s supposed to be to support the branches of the tree when they are covered in snow, but seeing as Tokyo only gets a light sprinkling of white stuff three or four times a year, I have an idea that they’re more ornamental now. There’s a good explanation of Yukitsuri at: http://search.japantimes.co.jp/cgi-bin/ek20070220wh.html
The Horikiri Shobuen is near Horikirishobuen Station on the Keisei Railways main line. It’s a nice place to visit if you’re in the area, but probably not worth a long trip.