Mulches can be a gardener's best friend.
They inhibit weed growth, hold soil moisture and can add nutrients with breakdown.
Living mulches can be a blessing and a curse.
If ivy were used it could choke out the other plants you are trying to grow.
Here is an example of a living mulch blessing:
The mulch is Marjoram (center and right), Oregano (left).
They surround some Old Fashioned Yellow Roses, plus a large rock.
The roses are special ones given to me by my husband and very fragrant too.
These herbs die back in the hard winter, but come up every spring.
I harvest and dry the herbs monthly for winter use.
The bees LOVE the flowers.
Some sweet Forget Me Nots are growing in the Oregano.
And you can see the first rose bud of the season.
Other mulches are straw, leaves and wood chips as in Back to Eden method.
I would not use hay because of grass seeds.