Tomatillos are relatively trouble-free in terms of pests, but the plants are not self-pollinating. You need at least two tomatillo plants for the yellow blooms to form fruit. Grow just one, and you’ll only have a plant with yellow flowers. Also, the pollen tends to clump at high humidity, sticking to the inside of the flower so it can’t be transferred to another flower—and that means no fruit. The last challenge with tomatillos is finding seedlings. This is one veggie you may need to grow from seed yourself.