Cyms are tough as nails. Also hungry... I have found that along with my usual (very light) general fertilizing with a pump sprayer, I give them some time-release fertilizer in the spring (like Nutricote) Since I started doing that, they grow and bloom much better... the light spraying works for most of my collection, but the heavy feeders (like Cyms and the Catasetinae) like that extra shot during the growing season.