Alex is right of course.
I really should have addressed that.
You do need to consider interplanting distances.
Some wildeflowers have extensive root systems (that's how they survive drought conditions). You can often get optimum plant distances from seed catalogs/on-line sources. Basically, for Plants A and B, a good rule of thumb is In-row planting distances of (A+B)/2.
For example, tomatoes should be planted at least 24" apart and sunflowers should be planted 24" apart. Ideally, there should be 24" distance between the tomatoes and sunflowers. They both require height and width room -- in other words, they are not ideal companions. However, a short-growing marigolds could easily live under tomatoes at the edge of the 24" circle, and cosmos, although tall but being very open stemmed, could live close to the tomato foliage and the tomato leaves would help hold them up. Lettuce could live under taller wildflowers that prefers moist soil.
Give some thought to how the roots and foliage grow to minimize competition, and what the water requirements are, etc. to optimize care.
The flowers you mention tend to grow well in drier conditions, which means they have deep roots and are efficient water uptakers -- which will tend to dry out the surrounding soil. They probably won't do as well grown with veggies that need lots of water.