Buttercup (Cucurbita maxima)
Buttercup squash are sometimes confused with kabochas, but buttercups (as you might expect from the name) have a 'cup' (as you see in the photo above). Buttercups originated in the mid 1900's in the North Dakota State University squash breeding program. In our project we have evaluated quite a few buttercups. Some of those that are high performing in other regions of the country did not do well here as they are very susceptible to western Oregon storage rots. Of all the buttercups we tested, the hybrid 'Bonbon' bred by Johnny's Selected Seeds performed the best. Bonbon is a beautiful, glossy buttercup with a large protruding 'button', weighing in at 2-4 pounds.
We do not consider Bonbon or other buttercups true WINTER squash in western Oregon when grown with overhead irrigation, as they are susceptible to storage rots and most don't make it into December. However, dryland-grown Bonbon stored much longer than irrigated Bonbon in our 2016-17 dryland/irrigated production and storage comparative trials, so it is possible that dryland Bonbon could become a true Oregon WINTER SQUASH - but more years of evaluation are necessary to confirm this.
Bonbon has also stood out in trials at Fedco Seeds in Maine, due to its attractiveness, productivity, resilience to fluctuating environmental conditions, and great flavor.