as long as the weed suppressant membrane allows water to drain freely, I'd go for that.

I would go for the plastic sheeting with the holes in the bottom if you have to. You could give the wooden planter a treatment with wood preversative inside and out first of all as it looks like a softwood construction. My best advice would be to plant your rose in the garden where it will not be starved of moisture as it will certainly outlive the planter.

Thanks both.I have applied the first of two coats of wood preservative and have found some weed membrane. The rose was not happy in its original spot in the garden so this is the only other sunny spot I can offer it. I checked with DA roses and this container size is what they recommend. My fellow garedening friend grows all her DA roses in containers and they look so healthy and seem very content. Will post a photo of finished result. Thank you both again.