Blender has an IvyGen addon built-in which can be used to create ivy growth on any object or surface. There's also many 3rd party ivy generators and addons which work very well for growing realistic looking ivy on surfaces, but I'd start by checking out the included IvyGen addon first. Unless you want to just do it as a texture/material, but most of the time I feel like that doesn't look as good. It can be useful as a way to include more detail, but I think at least some of the ivy and grass need to be geometry to really give it that extra detail.

Unlike Ivy, I think grass can be done mostly with just textures/materials. Maybe include just a few blades of real geometry here and there to make it pop, but grass and dirt can go a long way with displacement and normal maps. What's your plan for doing those?

______________________________________

My Store
My Free Models
My Video Tutorials
My CG Animations
Instagram: @luxxeon3d
Facebook: https://www.facebook.com/luxxeon