posted 5 years ago
I grow sweets as a perennial, but I do occasionally dig the beds up and start anew. It gives me the opportunity to add soil amendments. But I do have a couple beds that I pretty much ignore for 2 years or more before I harvest them for livestock feed. So at least in my location, it's a perennial that can be in the same spot for quite a while, if I wish.
Pests.....yes, that can become a problem from time to time. My number one destructive pest is whitefly. If they visit one of my sweets patches, they can really knock the plants hard, causing all the leaves to fall off and most of the stems to die back. Eliminating sweet potato whitefly has been impossible so far. So what I do is harvest everything that's above ground (feed it to the livestock), rake off any mulch and incorporate it into a hot compost pile, and add 2"-3" of compost atop the ground to act as fresh mulch. What grows back usually looks good for another year or longer.
There are several other nasty sweet potato pests here in Hawaii, but the whitefly is the only one that has found my farm so far.
I've noticed that some varieties are better at being perennial than others. Okinawan shows up everywhere if I leave even the tiniest root nodes behind. Old Maui White isn't as aggressive, but it has proven to be a stayer in the perennial department. But other varieties don't seem to rebound as strongly. So perhaps which variety one chooses to grow might be important.
I haven't done a lot of experimentation with sweets, but I have learned that there is great variety among them. Some have short vines, others are longer. One I've grown was so aggressive with 30' + vines that I had to eliminate it. It was overtaking everything near it. Some are bunching types with the tubers right under the mother plant. Others produce their tubers away from the mother plant. Some make large tubers, others make small. Some produce almost no tubers at all, but massive amounts of leaves and vines. There is lots of variety in sweets.
It's never too late to start! I retired to homestead on the slopes of Mauna Loa, an active volcano. I relate snippets of my endeavor on my blog : www.kaufarmer.blogspot.com