The mizzurani are not as difficult as you think they are.

Try find a seed without them. But there are more aggressive species out there that can replace the mizzurani. Keep playing with the mizzurani and you'll progress a interesting storyline with them.

A seed with the plant loving species can benefit you greatly. If i remember correctly they also stock cures and their items are well priced while also providing you transport missions. Go watch some gameplay vids to get tips from those more experienced.