Can't see enough from the pic to say for sure. A couple more pics would help, including a closer view of the seedpods, and a shot of the whole plant. If it's a woody shrub, it's probably meadowsweet or hardhack spiraea, which make pretty good arrows if you can get them seasoned without checking. If it's a herbacous perennial, they generally don't make great arrows. People have made arrows from goldenrod, horseweed, etc. but they are usually lightweight and don't hold up too well. You should have several kinds of hardwood shoots in your area, like red osier dogwood, silky dogwood, viburnum, privet, bush honetsuckle, hazelnut, and such.
