Last fall/early winter I found an Euonymus bush (still unsure about which exact species) in a forest preserve and collected some seeds. I assumed that it had already been relatively cold for long enough that I wouldn't have to cold stratify them and put them right on a heating pad and have kept them warm/moist since then.
I've read that they can sometimes take a long time to germinate, but besides some seeds obviously swelling with water, there have been no signs of life and I'm wondering if there would be any downside to throwing them in the fridge for 7 weeks and then going back to the heat? Should I just wait it out or chill them?

Euonymus seeds are quite oily (on the outside). You may remember that they were slippery when handling them. The usual procedure is wash them in a bit of soap and water first, as it is believed this coating can inhibit germination. Be sure to rinse thoroughly afterwards.

Cold stratification ONLY occurs with seeds that have already imbibed water. Dry seed given a cold treatment as was the case when you collected them, is simply seed storage. It is not cold stratification. Euonymus species seed in general are very erratic germinators and usually require at least one cold cycle, or at least one warm then cold cycle to germinate.

So if they are still in water, I would wash them with a drop of soap (even the swelled ones), plant them, and start you cold treatment in the fridge. Around mid March, I would put them outside in the shade, enclosed in a clear bag, to experience varying temps (deep freezing is fine), and let them germinate at the temperature that they want. Heating pads are rarely a good thing for seeds of temperate woody plants. Some woody plant seeds will want to germinate at 50F or even 40F, and won't germinate at 70+F.

Leftwood said:Euonymus seeds are quite oily (on the outside). You may remember that they were slippery when handling them. The usual procedure is wash them in a bit of soap and water first, as it is believed this coating can inhibit germination. Be sure to rinse thoroughly afterwards.

Cold stratification ONLY occurs with seeds that have already imbibed water. Dry seed given a cold treatment as was the case when you collected them, is simply seed storage. It is not cold stratification. Euonymus species seed in general are very erratic germinators and usually require at least one cold cycle, or at least one warm then cold cycle to germinate.

So if they are still in water, I would wash them with a drop of soap (even the swelled ones), plant them, and start you cold treatment in the fridge. Around mid March, I would put them outside in the shade, enclosed in a clear bag, to experience varying temps (deep freezing is fine), and let them germinate at the temperature that they want. Heating pads are rarely a good thing for seeds of temperate woody plants. Some woody plant seeds will want to germinate at 50F or even 40F, and won't germinate at 70+F.

Thank you for the advice. I've washed them and thoroughly rinsed them, and in about a month I'll follow the rest of your advice.

If any have visibly imbibed water, don't let them re-dry. Keep these moist, or barely moist, at whatever temperature you feel appropriate. Most seeds don't tolerate this kind of back and forth, once the process has begun.

Wow! This is some great information. I didn't know any of this about germinating euonymous seeds. Thank you for posting all of this great information.