Yellow primroses are a perennial plant that is best planted from seed. Depending on the variety, you may see yellow blooms 3 to 6 inches across in late spring on a plant 6 to 36 inches tall. The blooms may be one per stem or multiple blooms per stem, as seen on the yellow evening primrose, which is drought tolerant and reaches 1 to 2 feet tall. Plant yellow primrose seeds in spring or fall; they require little care and bring years of beauty to the garden.
Choose a sunny to partial-shade location to plant yellow primroses. Use a shovel or rototiller, depending on the size of the area to be cutivated, to work the soil down to about 8 inches. Work about 25 percent organic matter, like compost or leaf mold, into the tilled soil using a garden rake. Lightly moisten the tilled area.
Cast seeds over the tilled, moist soil. Primrose seeds are very small. The seeds can be mixed with dry sand to help you visualize where the seeds are landing. Cover the seeds with about 1/4 inch of soil. If seeds are planted in the spring, mist them about every 7 days until they sprout.
Thin out the number of sprouts when they have 2 to 3 leaves. Thin by gently pulling out weaker sprouts so the strong sprouts are about 3 inches apart. Apply commercial pesticide products according to manufacturer's instructions when spider mites, slugs or sow bugs are present.
Water every 7 to 10 days unless it rains.
Spent blooms will lead to seed pods that will mature and release seeds in the fall, expanding the number of plants that will appear the following spring. To control the growth, the seed pods can be removed.