2"x4" Rectangle Ikebana Kenzans,k61 From Hollow Creek Bonsai 2"x4" Black Rectangle Ikebana Kenzans,k61 From www.hollowcreekbonsai.com . Known by many different names Pin Frog, Flower Frog, Flower Spikes, Needle Holder and Kenzan it is a must for flower arranging enthusiasts. Flower frogs are reusable pieces of lead with small spikes that hold flowers in place within the arrangement.