Translation:I plant eggplants in my garden.
Aubergine is the more usual name in England. I had to look it up to make sure they were the same thing. I'd heard of it but guessed it was something different.
I tried I am planting aubergines in my garden but duo will not accept the obvious translation of aubergine or the present continuous
Both are accepted, but you probably used "some aubergines" and the list of translations, by default, did not include "some" because it is not needed. However, I added it as optional and acceptable.
Please note that in British English we don't use the word eggplant. We use aubergine.