To make my ikebana flowers last longer I usually trim down the plants that die and challenge myself to rearrange with what I have left or maybe add something that is bloom from my neighborhood. We got lucky and seem to live next to a lot a wooded places that might not miss a branch here and there.
A week or so ago, curly willow and mums can last longer than your average flower, I got curly willow, blazing star and baby mums from Awesome Blossoms and arranged them in this post. The blazing star got a bit crispy so away they went. Everything is a little dead outside being January and all so no more fillers. Though what this arrangement really needs is some greenery to spice it up.