We’re now firmly in the season of full-flowering for many herbaceous perennials that will continue through late September. Plants such as Kniphofia and hardy hibiscus are just starting to flower, as are many ornamental grasses. One group of plants that never fails to impress during the month of July is daylilies. This group of plants is huge and growing every season. More plants are introduced every season. A quick search on Google showed more than 80,000 cultivars of the genus Hemerocallis (daylily). Here at Heritage Museums & Gardens we have around 800 cultivars (and I thought that was a lot). So how do you sort through this genus and find the one (or several) cultivar(s) that work in your garden? I have a list of criteria I use:
• First, are they hardy in our zone (use zone 6 minimum)?
• Look for plants that are rebloomers. There are many that are rebloomers, and this should be on the list. Daylilies can flower for a few weeks, or they can flower, pause for a few weeks and then bloom again later in the season. There are cultivars such as Happy Returns, a nice clear yellow that is small in stature and has two flowering periods.
• Choose large, medium or small plants based on where you’re using them. Many newer cultivars are small (24 inches to top of the flower scape). Others can grow to 36 to 42 inches in height.
• Of course, flower color and style are important traits. You want colors that you like and that work in your garden. There are many new cultivars that are bold colors or have interesting color patterns in the throat of the flower.
• Consider a tetraploid. These hybrids have twice the number of chromosomes as normal daylilies (diploid daylilies). This means the flowers are usually larger and have more saturated colors. The foliage and flowers are typically thicker, and the stems are also stronger. They also grow a bit slower and are not good plants for mass planting.
I have lots of Happy Returns because I like the size of the plant and I love the clear yellow color. But I also love tetraploid cultivars and have several. There are many breeders of the genus Hemerocallis, and there are many, many cultivars that are worthy of space in the garden. I’ve bought several that have been bred by Dr. Darrel Apps. He at one time owned a large daylily nursery in New Jersey and now is retired—but is still growing and breeding daylilies. His newer plants are now available from a small garden center in Wisconsin.
If you’re looking for a plant for a sunny location that will tolerate some drought and is pretty well indestructible, consider daylilies. And, if you’re going to consider them, use the guide above. These plants will last a lifetime. It’s worth investing some time and doing some research to find the right plant for the location. At Heritage, we’ve been investing in some of the new cultivars to help homeowners choose the right plant for their location.