This appears to be a harmless slime mold, which can creep around a bit as it moves almost like an aemoeba, seeking food (just organic matter, not live plant tissue) and producing spores before dying back. They can be quite common on mulch, for example, where they often look a bit different because they don't spread out as much. If so, the residue will weather off in time, or might rub off with your fingers. If the plant does have an insect or disease issue (which based on how it looks, we don't think it does), then symptoms may spread or worsen. If that happens, feel free to send us new photos for assessment. For now, though, based on how the plant looks, you won't need to do anything and new growth should emerge normally as the plant establishes.

Miri

I actually looked at it again today, and noticed this weird, clear, thin, jelly-like substance on the leaves! That makes sense now. Glad to know it's harmless! Thanks. I still don't have any flowers on the plants yet, though. I wonder if it will produce any this year.

It's possible the plant is too young to bloom, or isn't getting enough light (if it's not in at least 6-8 hours of direct sun). If the residue changes again and seems to be associated with leaf damage later, feel free to send us more photos for evaluation.

Miri

Ok, thank you for your help! It did have flowers when I planted them, but I was advised to remove them so it could focus on root growth and also apparently those wouldn't have grown into nice strawberries because they were such early flowers.

Yes, that makes sense, okay. They'll establish a good root system this season, then, and will likely flower and fruit normally next year. If useful, you can visit our Growing Strawberries in a Home Garden page for more tips as they plant(s) grow in.

Miri

Ah, I see. Thanks for the info! :-)

You're welcome!