I’ve been growing Perilla frutescens for years in Copenhagen, Denmark. Within the genus Perilla, there are seven recognized chemotypes—meaning not all perilla is the same. Some may know Japanese “shiso,” which differs from Korean “kkaenipp.” In Denmark, where we have a large Vietnamese community, perilla is cherished as “tia to.” My best friend, who is Vietnamese, introduced me to this variety, which is distinct from the Japanese and Korean types.
All perilla varieties share day-length sensitivity: they thrive in long summer days but prepare to flower and seed as nights lengthen. This can be challenging at Copenhagen’s latitude (55.7°N). Of all types I’ve tried, Korean “kkaenipp” (Perilla frutescens var. frutescens) flowers the latest, making it impossible for me to produce seeds here, before frost. In contrast, Vietnamese “tia to” (Perilla frutescens var. crispa f. viridis) has a different flowering timeline, allowing Danish-Vietnamese families to grow it year after year from their own seed - even self-seeding, while im looking sadly at my korean “kkaenipp” and begging it to flower!
My question: Does anyone have advice or experience with adapting “kkaenipp” to shorter growing seasons—and/or access to less day-length-sensitive seed? Thanks
You can trick the Perilla to flower sooner by blocking out the light yourself. That’s what I’ve learned from Speed Breeders. If your Shiso plant is small enough, place a tarp or Bucket over it for like a whole day & it should signal to the plant that “Nights have gotten longer”.
I’ve personally noticed this effect but in reverse. I live in an apartment & have a forrest edge, on the edge I sowed a Shiso Patch. In that Patch is a Light from my Apartment Complex that shines on it virtually all night long. Specifically that side flowered much later compared to the shiso plants that were in a more shaded spot.
I don’t have specific experience with Kkaenipp, as this was simply the wild shiso I found in the woods that I planted there.
I actually tried the shading-method this year, but without much success. Maybe I will have to try again next year with more intense shading. I have heard of growers who selected for early flowering, and through that method got a less day-length sensitive variety. Given that I can’t mature seeds in Denmark, I think I need to start with seeds, which have a headstart on early flowering already.
Yea definitely, I remember the speed breeders said that the plants should be fully blocked out from light to trick the plants into flowering mode properly. If you have to prune your shiso plants to put a bucked over it with a Brick on top, so be it.
Absolutely start with those that have a headstart to flowering earlier but also include those that don’t if they have traits you value. Mixing up genes & re-selecting could get something even better. Who knows, what if a Mutation happens that makes your Shiso Day-Neutral?