I've been interested in switchgrass for a while, but here in New Zealand we cannot import seeds of this species, despite the fact it was widely grown back in the 1800's and there are still some plants surviving here. So now I have been sent some seeds from up North and my experiments are underway.
So what can everyone tell me about SG? From what I read it sounds like a super-plant, deep-rooting soil-building summer-active C4 that is still highly palatable pre-flowering. Are there any downsides?
My climate is unlike anywhere in USA, closest match would be Central California coast, but with a bit more summer rain. Our summers are quite cool compared to most of USA but the sunshine intensity is such that C3 grasses usually fade away no matter how much summer rain we might get, and in a dry summer or drought they go brown and just dust. Most of the C4 grasses that occur here like kikuyu (Pennisetum clandestinum) and Paspalum (Paspalum dilatatum) are considered weeds, but they do grow well and stay green in dry summers, being deep rooted and much better to handle high sunshine intensity and high UV levels. The downside to these is that they suppress other grasses that are much more productive in the other 3 seasons.
SG with it's C4 nature, deep roots, and tall stature sound ideal, specially in hay pastures mixed with legumes etc. One thing I wonder about is what is does in winter here, our summers have similar heat accumulation to the cooler parts of switchgrass natural range, but at the same time when it comes to winter extreme cold temperatures we are equivalent to USDA zone 10 (I also have a few acres that are probably the warm end of zone 9). Will switchgrass tolerate a winter growing annual grown in the same field in the off-season?