There seems something surreal about the idea of Raisin Tree (Hovenia dulcis) seeds. Really? Seeds that will grow into a tree that bears raisins? Got some magic bean stalk seeds too? The bright side to this species is that seed seems to be the usual method of propagation in the USA, and the very durable seed coat that slows germination should also result in a very long lived seed. The seeds are small, but quite beautiful. I can imagine that they might be of interest in bead work.
The raisins in this case are not dried grapes or currants, but rather the swollen, sweet fruit stems of the tree, after the fruits themselves, which are inedible, are fully ripened.
JLHudson’s catalog says to nick the seeds and plant them in warm temperatures to sprout in 4-8 weeks.
California Rare Fruit Grower’s page on the Raisin Tree suggests nicking the seed, sowing in potting soil, covering with clear plastic and placing in bright light. CRFG also suggests that exposing the seeds to 140F water three times in three days will substitute for scarification.
PFaF suggests scarifying stored seed and planting in very early spring. It mentions that seed may not sprout for a year.
Reich states that nicking the seed should result in germination within a week to a couple of months.
I’m suspicious that this plant will give significantly better germination results with bright light or with very warm temperatures. The seeds were buggers to nick. I finally got a decent rhythm going with a pair of pliers and a small file. I can imagine that one of the other scarification techniques would be much preferred on a larger scale. I’m planning on nicked about twenty seeds, starting ten in direct sun inside a ziplock with a bit of paper towel as a moisture resevoir. The next ten are started in a similar fashion, but in less intense light. The remaining seeds I might start in refrigeration this fall.