Planting flowers in your vegetable garden adds color and attracts beneficial insects and pollinators. Asparagus can be stressed by too much competition from other plants so leave 8 to 12 inches between your asparagus plants and your flower seeds when planting. Cool-weather annuals are ideal for an asparagus garden; bachelor buttons, calendula, petunias, nasturtiums and snapdragons are all good, colorful choices. An asparagus patch will produce for 15 to 20 years as it is one of the few perennial vegetables.
Turn over your planting bed with a garden fork to loosen the soil. Dig in rich, organic compost to improve the soil. Once your asparagus patch is established you will only be able to add nutrients from the top so it is important to give your plants a good start.
Dig a trough that is 8 to 10 inches deep and 6 to 8 inches wide. Make a 3-inch mound of soil that runs along the center of the trough. The mound will support the long roots of the asparagus crown.
Lay the roots over the mound with the shoots pointing up. Cover the roots and the base of the shoots with soil; you should have a 4- to 5-inch trough remaining. Planting the asparagus lower then the soil level will allow you to add soil to the base of the plant as the growing season progresses.
Sow your flower seeds around your asparagus plants. Leave 10 to 12 inches between the asparagus and the flower seeds to avoid crowding the root systems. Plant flower seeds in the spring at the same time as you plant your asparagus.
Harvest asparagus after the second year by snapping off the shoot close to the base. Each year the asparagus will get a little thinner. When it is the width of a pencil allow the stalk to grow and go to seed. It will come back thick in the following year.
Thin the flowers if they get too thick and clip off the spent flowers before the plant scatters its seeds. Remove all the flower plant material each fall and re-sow the seeds in the spring.