Deer like to sample food sources, or browse, to test whether they like or dislike certain plants, young trees and flowers. Deer food preferences vary by region of the country depending on what deer consumed during previous browsings. Deer are creatures of habit and, if they liked a species of flowering annual in the past, they are likely to choose it again.
Deer are far less picky about what they will consume in winter and in early spring. During cold, snowy winters, when plant material is scarce, deer might choose to eat whatever is available, even plants they normally pass up. In spring, after eating little to conserve the calories needed to search for food, deer gobble up tender young growth.
In most areas of the United States, deer avoid flowering annuals like marigold, periwinkle, snap dragon, sunflower, sweet alyssum and zinnia. Planting these annuals may not guarantee that deer stay away from the garden, but it does reduce the chances of deer damage to plant material.