Osmanthus fragrans, sweet olive or fragrant olive, is an asian native shrub. It’s famous for it’s sweet scent reminicent of ripe apricots or peaches. There are two main groups of osmanthus fragrans, a white to yellow flowered group and an orange flowered group. I have grown white, -with a hint of yellow in the centre of the flowers,- osmanthus fragrans from seed. It is a bit tricky and you need a lot of patience but it is absolutely worthwhile. It flowers after a little more than a year after germination. For me it flowered for 6 weeks straight and my garden never smelled more heavenly! I keep it in a pot in an frost free greenhouse in winter. But I plan to plant it outside near a south facing wall when it’s older. I am still looking for orange osmanthus fragrans seeds, so if you have any tips on where to find them, I’d love to know!
It took a few experiments and a lot of patience (18 months!) but I hope my trials so far will make sowing Osmanthus fragrans a little easier for you.
Here’s what I did:
- Soak the seeds in luke warm water over night. (24-48 hours).
- Optional: fughicide powder, some of my seeds developed mold because of the long germiniation process. It can help to use a fughicide powder on the seeds before placing them in the seedmix. If you check on them regularly you can skip this step.
- Sow the seeds in seedmix. I found a mix with a lot of sand and little compost works best. I like to use a small container to use my growing space efficiently.
- Make sure your seedmix is moist but not wet. If it’s too wet, leave it to dry out a little.
- Place the container in a plastic seal bag. Open it once a week to let some fresh air in and check on them.
Now you have two options: the laid-back- follow-the-seasons-route or the trick-the-seeds-into-germinating-route. The seeds need a warm period (20 celciuls or more) and a cold period (below 5 celcius) to germinate.
- The laid-back-follow-the-seasons-route: place the seeds outside in a sheltered spot out of direct sunlight. Make sure to set a reminder in your calender in the autum so you can place the container in a cellar, garage or cool room in your house when there is a chance of frost. Place them ouside again in spring and germination will follow in summer. If you have the luxury of a greenhouse, you can just leave the seeds in there and you don’t have to move them.
- The trick-the-seeds-into-germinating-route: place the seeds in a warm spot. That can be outside, in a sunny windowsill or on a heatmat (25C). Leave them there for 6-8 weeks. Than, place the seeds in the fridge for 6-8 weeks. When you take them out of the fridge, leave them to acclimate for a day or so before giving them a warm spot again to germinate.
If not all seeds germinate, give them time. For me it took about 2 months after taking them out of the fridge for the first one to germinate. But it highly depends on your growing conditions. From the 10 seeds I’ve sown first time around, I lost 3 to molding/rot, 4 germinated the first time when I took them out of the fridge to the heatmat. I placed the rest of the seeds in my greenhouse and 2 have germinated a year later. The last mohikan is still sitting in a pot in it’s little corner waiting for when the time it right.
A while ago someone asked me if it helps to use saltpeter (a gardening salt) to germinate the osmanthus seeds. I had to admit: I don’t know because I haven’t tried it! So, I ordered some of this salt online after reading it can help germinating difficult seeds. And I am trying it out for myself. I will post an update on the results.
I have tried soaking the seeds in 50% orange juice and 50% water to help soften the outer skin of the seeds to encourage germination. I am not sure if it helped, I supect the change in temperature is the main limiting factor in germination, so I did not include it in this guide. It didn’t hurt the seeds, if you’d like to try it for yourself. If you have any questions or suggestions, please let me know!