Featuring trumpet-shaped blooms in a wide range of colors, daylilies (Hemerocallis spp.) grow well in large pots that have bottom drainage holes. Daylilies are hardy in U.S. Department of Agriculture plant hardiness zones 3 through 9 and grow 1 to 3 feet tall and 1 to 2 feet wide, depending on the variety. Dwarf daylilies perform better than standard-size varieties in containers. Grow one daylily plant of any variety per pot.
Planting at the Right Times
Daylilies can be planted year-round in some USDA zones, but the best planting times in all zones are spring and fall. In areas that never experience frosts, daylilies can be planted in pots any time of year, but planting in spring or fall allows the plants time to establish good root systems before flowering. If you live in an area with cold winters, then plant daylilies after your location's last average annual frost date in spring or about four weeks before the first average annual frost date in fall.
Large pots provide the best growing conditions for daylily root systems. Daylilies that grow 1 foot wide and tall need pots at least 12 inches in diameter, but pots 15 to 18 inches in diameter are best. Larger daylily varieties need larger containers. For example, pots for plants that grow 2 feet wide should be at least 24 inches in diameter. Each pot must have drainage holes in its bottom.
Spread general-purpose potting soil in a layer 2 to 3 inches deep over the base of each pot.
Remove the covering and ties from each bare-root daylily, and place the plant's roots on the potting soil in the plant's respective pot. Alternatively, remove each daylily plant from its nursery container, and place its root ball on the potting soil of the plant's new pot.
Add potting soil to, or remove it from, the base of each pot so that every daylily sits at the correct depth. The base of the shoots of a bare-root daylily should be 2 inches below the pot's rim, and the base of the shoots of a container-grown daylily should be 1 inch below the pot's rim.
Add potting soil to fill each pot to 1 inch below its rim. The base of the shoots of a bare-root daylily should be covered by 1 inch of potting soil.
Place the daylilies' containers in their final position, a sunny or partially shaded area of the garden. Daylilies that have flowers in pastel shades look best in partially shaded spots.
Pour water slowly over each container's potting soil surface until the liquid flows through the drainage holes.
Watering Daylilies in Pots
Daylilies in containers flower best when they grow in evenly moist potting soil. Water the daylilies when the potting soil surface is dry to a depth of 1 inch. Apply water until it flows through the drainage holes, and let the pots drain before putting them on their drip trays. During hot, windy weather, daylilies in pots may need water every day.
Protecting Them from Frost
In USDA zones 7 and lower, daylilies in pots need frost protection. Daylilies die back in fall in areas with cold weather. After the first frost, place the potted plants in a frost-free garage or shed until they produce new shoots in spring. Another option is to group the potted plants outdoors and cover them with a pile of straw so that the pot rims are buried 4 to 5 inches deep. Spread burlap or old blankets over the straw if the plants are in a windy area.
Daylilies don't need water when they aren't growing, but you can water them very lightly to prevent their potting soil from completely drying out.