Yellow Gem appears to be infected with a dahlia virus, most likely Dahlia Mosaic Virus. It has tested negative for every other common dahlia virus and DMV is the only one that I cannot test for. The effect of this virus is pretty minimal, other than causing some yellowing of the leaves, and it is extremely common in dahlias. The plants still flower well and produce plenty of tubers. So, it is your call. If you grow a lot of dahlias and you want to keep them disease free, you should probably not buy this (on the other hand, if you grow a lot of dahlias, you probably already have some that are infected). If you are just growing a few dahlias for food, it might not matter to you. I will keep trying to clean up this variety, but DMV is capable of integrating into the host genome, so cleanup may not be possible.
Yellow Gem is a high yielding variety with round to oval, off-white tubers. The tubers are firm and juicy, with a very smooth texture after cooking. Flavor is neutral in fall with just a hint of sweetness and floral aftertaste. By spring, the tubers are very sweet. Small, yellow “pom pom” type flowers. Grows to about 3 feet. An older variety, dating to 1914. Tolerates overwintering in wet soil better than most varieties, which helps to sweeten it.
We had a hard time tracking down a source for this variety. It appears that many ornamental growers have dropped it in favor of more showy varieties. Perhaps we can help it to gain some popularity and live on as an edible.
Although we sometimes offer tubers of these varieties, my main focus is producing seed for breeding. Like all dahlia seeds, the true seeds of this variety will not be true to type. I have grown out quite a few and got a range of types, predominantly single flowered and ball types. Many of them have tubers with good edible qualities.