If your soil doesn't already have fertilizer mixed into it, yes. Cannas grow like mad when fertilized. Any good fertilizer (I used MiracleGro), applied according to the amounts on the label, will help immensely.

I typically use a controlled release fertilizer like Osmocote that lasts several months. In addition to this, they get a good dose of a water soluable fertilizer like Peter's or MG every week or two. Rapid growers like canna seem to really appreciate the extra ferts.

Regards,

Rokal

Fish & seaweed emulsion is a great fertilizer, & you can spray it on the leaves, too.

I used Bulbtone under the theory that they were a bulb or tuber. Put them in good sized pots and they seem to be very happy so far