If you have access to well-rotted/finished compost, a mix of that with topsoil would probably work well. For many tropicals you want a moisture-retentive but well-drained soil with abundant nutrients for maximal growth and flowering (a number of tropicals like cannas are greedy feeders).

I can not recommend using Milorganite in addition to lots of organic matter as you have planned to add to the raised beds. Tropicals are heavy feeders and adding a good 10-10-10 fertilizer will help you get massive growth that will make you feel like you are in the tropics.

Ooops, I meant cannot recommed it ENOUGH....Milorganite that is....I have had the best growth especially in my tropical and cold hardy tropical beds.

the virginian I used milorganite last year based on your recommendation. I used it on my lawn, my bananas and potted palms. My lawn loved it but I didn't really notice any dffrence one way or the other on all else. But we had an unseasonably cool summer last year and it is hard to tell if weather had a detrimental affect on the milorganite. I'll try it again this year.

Hi all just joined a few days ago and just love this website. Just wanted to mention with seaweed be careful of the salt levels as that can harm the roots.

Scott

here in vancouver WA my tropicals do best if i dig up allllll the clay and replace with a mix that is mostly peat with worm castings and some perlite... i have an oleander that loves it.

As with any fertilizer used on tropicals, the warmer the better for results and if you had a cool summer they would not be able to use the Milorganite to have the supercharged growth. You will see better results if you have a nice warm rainy summer and let's hope we all get one. As far as soil amending, I would never remove the native soil as all you are doing is creating a TUB for the plant to spin its roots around itself once it hits the native soil. It won't happen right away and may take a few years, but the plant will get root bound when it can't penetrate the surrounding clay. Tropicals in my yard seem to love compost and leaf mould amended red clay.