Stella de Oro daylilies are popular hybrids valued for their ornamental flowers, blooming habit and ease of care. The plants bloom during early summer, producing clusters of attractive yellow flowers. The flowers form on stalks that rise up to 2½ feet above the foliage, making them easily visible from most locations in the garden. Native to Asia, Stella de Oro daylilies thrive in USDA Plant Hardiness Zones 4 through 11, and are successfully cultivated in most temperate regions around the world.
Plant Stella de Oro daylilies during early spring just after the final frost of the year in a location that receives six to eight hours of full sunlight each day. Spread a 2-inch layer of organic compost over the planting site and use a garden tiller to work it into the soil to increase fertility prior to planting. Space Stella de Oro daylilies 12 to 14 inches apart.
Apply a 3-inch layer of mulch to the soil surrounding the plants during summer and winter to deter weeds and protect against extremely hot or cold weather. Remove the mulch at the end of each respective season to allow normal growth to resume. Do not mulch during spring and fall.
Water the plants once per week during the first spring and summer of growth. Reduce watering frequency thereafter to once every 10 days during spring and summer, and once every two weeks during fall and winter.
Fertilize Stella de Oro daylilies once per year during spring with a side-dressing of organic compost. Spread a 2-inch layer of compost over the soil surrounding the plant and it will release nutrients into the soil as it decomposes. Do not allow the compost to touch the plant, as this increases the risk of disease.
Remove faded flowers, a process known as deadheading, before they turn into seed pods to encourage the formation of additional blossoms the following year. Pinch off the flowers close to the stem to minimize damage.