My garden contains roses, shrubs, gazanias, ornamental strawberry and weeds (such as Hieracium vulgatum (hawkweed); Euphorbia (spurge); Senecio vulgaris (common groundsel); Medicago lupulina (Black medic, nonesuch), and Galium aparine (Velcro plant or cleavers).

I plan to remove the gazanias, ornamental strawberry and weeds - stems, roots and all -- then lay down cardboard and 3 to 4 inches of bark chunks.

Will this prevent the re-growth of the removed plants?

Or should I also apply a weed preventer (or other product) before I lay down the cardboard to stop these removed plants from re-growing without affecting the roses and other shrubs?